Final Report Summary - WEEVIL STOP (Development of a cost-effective and sustainable insecticide-free plant protection method, eliminating widespread catastrophic damage in the forestry caused by the pine weevil Hylobius abietis)
Executive Summary:
The large pine weevil (Hylobius abietis) is the most destructive pest in re-forestation of conifer forest across Europe, Russia and Asia. If the planted seedlings are not protected against the insect, costs in the range of 140 million EUR a year for the forest industry and society may be the consequence in EU-27. The use of highly toxic insecticides has been the practice for many years to suppress the pine weevil problem. The EU aims to substitute the insecticides with non-chemical methods. The Weevil STOP project, running for 3 years from October 2012, worked on enhancing the knowledge of substituting the insecticides with wax as mechanical protection and developed a machine to apply the wax on each individual seedling in the nursery.
Researchers from the University of Oslo studied the effect of wax thickness and heights and found that the plant fitness and shoot production was good as long as the wax coating was less than two thirds of the seedling height. A number of waxing tests showed the importance of wax temperature control and particularly rapid cooling after the wax application.
The importance of sufficient wax thickness was shown in a growth experiment where the stem diameter increased more than 200 %. Here a wax layer initially about 1.5 mm thick showed a low cracking tendency while thinner layers showed cracking.
Degradation tests on wax in soil showed that the degradation rate was low in cold soil (8 oC) and significantly higher in warmer soil (20 oC). A biodegradation test (OECD) showed that the wax used biodegrades slower than beeswax but that the wax was biodegradable.
Researchers from Swedish University of Agricultural Sciences found in laboratory experiments that the protective effect of wax treatment is affected by wax thickness. The performance of the wax coating increased with the thickness of the wax layer. The results showed a threshold in protective effectiveness between 0.6 mm and 1.0 mm wax thickness. The protective effect of wax treatment was also investigated in two controlled field tests (in 2014 and 2015) and in practical forest plantations (2015). In the two controlled field tests a lower proportion of wax treated seedlings were killed by pine weevils in 2015 (1.3%) than in 2014 (4.1%), while equal proportions (approx. 30%) of control seedlings were killed by pine weevils.
In the field test started in 2015 only 3% of the wax treated seedlings and less than 1% of the Merit Forest seedlings were considered as killed by drought. The inventories of practical plantations showed low seedling mortality for wax treated seedlings, both regarding mortality caused by pine weevil feeding (4%) and by drought (4%).
A prototype machine was constructed by the institutes Teknologisk Institutt from Norway and Labor from Italy. This machine was placed in a nursery in Estonia. More than 200,000seedlings where wax treated in January 2015. A large portion of these seedlings were used in field trials and practical plantations in Sweden with the results describe above.
The capacity requirement for wax treatment was 60 seedlings per minute in the nursery and in shorter periods the machine tested 50% above this requirement. The waxing and cooling procedure allowed the seedling to be packed within 2 minutes after treatment.
Based on the experiences from the nursery in Estonia the treatment cost is below
0.05 EUR per seedling
Project Context and Objectives:
The large pine weevil (Hylobius abietis), a small insect the size of a fingernail, is the most destructive pest in tree planting and re-forestation of conifer forest across Europe, Russia and Asia in terms of economic damage caused.
This insect is often present when planting after clear-cutting because it is attracted to the area by volatile compounds released from the stumps, and it will breed in the stumps for some years.
If the planted seedlings are not protected against this insect, costs in the range of € 140 million a year for the forest industry and society may be the consequence in EU-27.
Re-forestation practice has for many years been depending on using highly hazardous insecticides to suppress the large pine weevil problem.
The insecticides are often highly toxic for both animals and humans and the EU aims to substitute the insecticides with non-chemical methods. Non-chemical methods means alternative methods to chemical insecticides based on forest techniques and/or physical or biological pest control methods.
Our project has developed an environmentally friendly, cost efficient, non-chemical pest control method against the large pine weevil. It is a physical plant protection based on a highly refined wax formulation that is applied once on the main stem of conifer seedlings in the forest tree nursery before the seedlings are distributed for planting in the forest. Correctly performed the protection from wax will last for two years, which is the most critical time period for pine weevil attacks.
The EU-27, represented with 158 million ha of productive forest, is the sixth largest forest area in the world with an annual increase of almost 0.5 million ha due to intensive forestation and re-forestation activities.
Coniferous species cover 45% of total productive forest areas in EU-27. In 2011 alone approximately 1010 million coniferous seedlings (mostly pine and spruce) were planted. Of these 40% were treated with insecticides as protection against the pine weevil.
Tree planting and re-forestation is a very important part of Sustainable Forestry Management and essential for securing access to wood as a raw material for forest-based industries. A competitive forestry output enhances the competitiveness of the industry. Forest protection against pests is an integral part to achieving strong competitiveness over time.
The European forestry and forest-based industries provides more than 3.5 million jobs, many of them in rural areas where people have limited job opportunities.
The Weevil STOP project addresses the need of the European Private Forest Owners Community which has almost 16 million private forest owners, most of them being SMEs’.
The private forest owners manage approximately 60% of Europe’s forests with an average forest size of 13 ha.
The large community of Private Forest Owners is threatened with significant economic loss due to the prohibition of hazardous chemicals as plant protection products, and face great challenges to meet the new EU Directive on Sustainable use of Pesticides (2009/128/EC), which requests the implementation of integrated pest management and that priority is given to alternative non-chemical methods of plant protection.
A proactive approach to prepare for forest practice without insecticides was taken by some SME-AGs of Private Forest Owners from Norway, Sweden, Estonia, Latvia and CEPF in Brussels in order to launch this trans-national project plan for Weevil STOP in 2012.
Several SMEs working in the forest sector in the Nordic countries joined in and formed the consortium, including also a machine builder from Italy and a specialized wax supplier from Norway.
The overall technological aim of this project was to develop an automated process for the precise covering of the main stem of conifer seedlings (1 and 1.5 year old conifer seedlings) with a highly refined wax that provides mechanical protection against the pine weevil. The technical solutions had to be robust and reliable as well as economically cost efficient, in order to work in the nursery environment.
A developed gripping and picking machine based on modern robotic technologies was to be used to pick out seedlings from all kind of plant containers and placing them into single holders. A novel wax application process was to be developed to be able to apply the melted wax precise on the lower part of the main stem (the machine task given to Teknologisk Institutt from Norway and Labor S.R.L. from Italy).
More specifically this task involved developing a wax application process that applied wax on the seedlings main stem and less on branches, coated maximum 60% of the stem length from its base and upwards, and applied a layer of wax with thickness above 0.6 mm, preferably in the range 1.0 to 1.5 mm, on the stem.
The minimum capacity for the machine was set to 60 seedlings per minute, which equals an annual capacity of 2.3 million seedlings (season: 80 working days with 8 hours per day). The method should be scalable to an annual capacity of up to 18 million seedlings per year.
To make the system economically within reach for smaller nurseries the target investment cost should be close to 100,000 € for a basic unit and the treatment cost for 1000 seedlings maximum
50 €.
The scientific objectives of the Weevil STOP project were to gain advanced knowledge regarding the use of wax on young seedlings by studying wax-plant interactions and testing seedling quality (at the University of Oslo), investigate wax-weevil interactions and testing the protective function of the wax (at the Swedish University of Agricultural Sciences).
One of the main scientific objectives of the Weevil STOP project was to identify the wax coating specifications needed to achieve an optimal protection of the spruce seedlings against pine weevil attacks for 2 years, two summers and one winter season. Two of the main factors would be ensuring high plant fitness and good wax cracking resistance, making the wax stretch in accordance with the increasing stem thickness of growing plants without cracking. By using several wax cover heights, wax thicknesses and plant sizes the best specifications for wax coating were to be found. Further, the possibility of extending the period of applying wax on the seedlings in the nurseries was to be studied. If the period could be extended, the capacity of a single nursery to produce wax coated seedlings would be increased. Finally, the degradation of the wax was to be studied, to ensure that it would not degrade before the two-year protection period was completed and to investigate the biodegradability of the wax.
The overall performance of the developed system for protective function of wax towards feeding pine weevils should finally be evaluated in comparative field trials and in practical forest plantations.
Project Results:
The development of the waxing machine
Concept of layout: The main elements of the machine are a pick and place unit, a conveyor belt loop system integrated with a screw transporter, a novel wax shower unit and a heated reservoir for the wax. The seedlings are removed from the trays by the pick and place unit in series of 9 seedlings and placed in individual cups. These cups are then transported on a conveyor belt to the waxing area. In the waxing unit the cups holding the seedlings are turned 80 degrees into a close to horizontal position, and at the same time moved forward by a rotating screw. A friction device forces the cups holding the seedlings to rotate while passing the waxing unit. During these movements, the seedlings are coated with wax from the root neck and 10-14 cm up, by several wax showers positioned above the route of travel. Immediately after the wax treatment the seedlings are cooled down by a cold water shower, and finally excess water is removed by forceful cold airstreams.
The pilot machine has been designed for containerized spruce seedlings, grown in system trays, and with a height between 15 and 28 cm above root neck. The pick and place unit has a limitation concerning seedling height, given by these criteria. In a new machine it is possible to design the pick and place gripers for handling higher seedlings. In the pilot machine, seedlings larger than 28 cm and up to a height of 40 cm above root neck could only be manually loaded into the cups.
The transport system has been designed to transport large volumes of conifer seedlings through the wax applicatıon unit and at the same time avoiding that wax and dirt enter the moving parts and cause malfunction. To manage these requirements, the project used
1) a transplantıng machine modified to be stronger than ordinary trans-planter machines for greeneries but modified for conifer nurseries
2) a contınuous conveyor system that was easy to clean for soil and spillages
3) an innovative spiral transporter was developed for transporting the cups through the waxing unit. This construction was able to turn the plants into a nearly horizontal position before entering the wax unit and rotate them through the waxing and the cooling units
4) a special cup design in aluminium was developed to hold the plants both in the vertical position as well as in the nearly horizontal position. These cups should be designed especially for the containers used in the nursery to ensure correct positioning of the seedling in the machine. The pilot machine used 200 of these cups which were loaded either manually or with the pick and place unit. The seedlings were manually picked from the cups after the waxing process.
The major challenges in the designing of the wax application system for conifer seedlings were related to the nature of the wax itself and the loose soil from the seedlings. The state of the wax changes from liquid to solid material within a few degrees of cooling. This behaviour easily creates build up of unwanted wax deposits in the machine. The seedlings have a tendency to create soil spillage from the root balls and also lose some needles. Together with the wax these deposits may increase the problems of keeping a machine running regularly. It was important to keep the liquid wax away from moving machine parts.
The wax melting unit (wax tub) was a central part of the machine. The unit was designed to have sufficient melting /heating capacity in order to feed the wax shower arrangement in use. A filter system was integrated on the top of the melting unit to prevent soil, needles and root parts from entering into the wax reservoir. These filters were easy to remove for cleaning of accumulated dirt. It was necessary to keep the wax in circulation in the melting pot when it was melted. The wax formulation contains a white pigment that has a higher density than wax and thus will precipitate out of the wax if it is not continuously stirred. To maintain the circulation two centrifugal pumps were used to circulate the fluid wax when it was kept at the 82 degrees Celsius operating temperature. These pumps would also operate the wax showers. The wax tub was constructed with two chambers, a “clean-wax” and a “dirty-wax” chamber. During operation with seedlings in the cups, the fluid wax was kept clean from the contamination of soil by several filters and sieves in the melting unit.
The liquid wax was applied from above at low pressure by means of a custom made shower system. This design can be adjusted to any seedling height by simply changing the perforated steel plates in the shower heads. The pilot machine had 2 shower heads, each with 4 individual showers, thus there were 8 showers available for each seedling passing the waxing area. The shower heads were placed approx. 1 meter from each other and in between there was a cold air fan to cool the first wax layer.
The wax layer on the seedling could be controlled by the number of showers being used and their positions along the screw transporter. In most cases a sufficient wax layer was achieved using 3 or 4 of the showers, keeping the others in closed position.
It was important to bring the temperature down to below 40 degrees Celsius immediately after the waxing process. The most efficient cooling of waxed seedlings is obtained by water showers. Controlled water cooling was possible with water showers when the seedlings were still nearly horizontal and rotating while moving along the spiral screw.
The pilot machine had a water reservoir with a pump that supplied 4 shower heads with cold water. This arrangement reduced the wax temperature to below 40 degrees Celsius within seconds after the wax application. At the end of the conveyor screw the cups and seedlings were repositioned to vertical angle and entered a cooling tunnel with cold air in order to reduce the temperature to below 20 degrees Celsius.
During the waxing season (winter) the indoor temperature at nurseries is low at around 5 degrees Celsius. Therefor the cooling water stays cold and there is sufficient cold air available for the cooling tunnel. In milder surroundings cooling units can be installed for the water and the air.
The prototype waxing machine was assembled at a workshop in Italy and started for the first time in February 2014. Following this there were several improvements done to the machine to ensure that it would operate well in the final testing in an appropriate nursery surrounding in a Nordic country. In particular it was necessary to adjust the cooling sequence and install the intermediate cooling unit. When running at higher speeds it was clear that the feeding system of the cups had to be synchronized with the pick and place unit. The machine was further optimized and tested for speed and synchronization in Italy in autumn 2014. It was moved to Plantex nursery in Estonia for testing in an appropriate industrial environment at the end of 2014. More than 200,000 seedlings were waxed with this machine during the test in Estonia in January and February 2015.
Already in May 2014 the first 1000 seedlings were wax-treated for long-term tests in Sweden and Norway. At this point the water cooling unit was not installed and only manual cooling in a bucket of water was used. Before moving the machine to Estonia a cooling unit was installed employing water showers and cold air. With this appropriate cooling unit in place approximately 200.000 seedlings were wax-treated in January 2015 at the Estonian nursery. These were used in forest trials and practical plantations in Sweden spring 2015, together with insecticide treated (Merit forest) and control seedling without weevil protection. The final machine was tested according to the objectives in the project determined at the beginning of the project. The wax application on the seedlings was correct regarding placement, thickness and quality. The capacity of the machine was 60 seedlings/minute and the waxing unit alone (without using the pick and place unit) exceeded this requirement by 50% in shorter periods. The cooling and drying of the plants after waxing was sufficient to pack the plants approximately 2 minutes after treatment. The Pick and place unit had limitations regarding plant size and velocity, and was quite complex to operate.
The tray system for growing the seedlings was different at the Plantex nursey in Estonia than the tray system used during the construction period of the machine. For this reason only the basic wax unit was moved to Estonia and the cups were loaded manually.
At the nursery in Estonia the machine proved to be robust and have capacity for high-volume production in an industrial environment.
From the experiences of operating the machine in the nursery environment, the technical manager in the Weevil STOP project and the institutes made a list of recommendation for the next generation of the pilot machine. Because the machine produced seedlings that tested well, the main principles and functions are recommended to be used in next machine. The improvements recommended are stronger materials for more robustness, simplify some details to improve cost efficiency, and change suppliers for better/cheaper components. Also it was recommended to offer to the market a basic semiautomatic machine with manual loading and discharging of the cups. An additional option is then to add a pick-and-place unit to feed the cups automatically from the trays.
For the machine construction and principles for waxing and cooling a European PTC patent application has been filed in Italy by Mr. Guerrino Zannier from Weevil STOP partner Electrozeta, the machine builder in the consortium. The submission date was 21st May 2015 and the patent application has the Italian application no 102015000016675.
Testing of the impact of the waxing process on plant quality of seedlings from the field and freeze storage during the winter, spring and early summer have shown the importance of controlled wax temperature and rapid cooling process after the wax application. Long-term (months) growth experiments with seedlings wax treated as recommended, showed no differences between the controls and the waxed plants in top shoot heights and side shoot growth. The waxing process gave a good protection quality of the wax against pine weevil attack and allowed a greater flexibility in the timing of wax treatment of the seedlings since the waxing can be conducted from December to July.
Unsatisfactory cooling of the wax can give wilting symptoms after six to eight weeks after planting in the field.
These results indicated that the wilting problem with waxed spruce seedling in field trials can be an effect of an unsatisfactory cooling process. A wax guidance explaining the waxing process has been made and is recommended (A. B. Eriksen and A. Vollsnes, 2015).
The effects of wax thickness and heights on the stem of the Norway spruce seedlings on the growth and development were studied by short term (weeks) and long term (month) experiments under summer conditions in environmentally controlled growth rooms at the University of Oslo. A number of combinations of three plant sizes, three wax thicknesses and six wax coating heights up to 100% wax covering of the seedling were conducted to test the extreme limits for the wax treatments and the interactions between seedling and wax. Covering too high percentage of the green parts of the seedling, gave a short-term decrease of the growth production. The fitness and growth of the seedlings was good as long as the wax coating was less than two thirds of the shoot height. During a four-month growth experiment in growth rooms, the stem diameter increased up to 200% posing a great challenge to the wax plasticity. When the stem diameter increased, the wax coating was stretched and became thinner, increasing the cracking tendency, as a thin coating will crack easier than a thick. The seedlings should be protected against pine weevils for 2 years by the wax barrier even though the wax coating was stretched during that period. The thickness of the initial wax layer should endure 2 years stretching. A wax layer 1.5 mm thick, showed a low cracking tendency despite large stem diameter increase.
Wax – pine weevil interaction studied in laboratory tests at SLU showed that the thickness of the wax layer was a crucial factor with regard to its protective effect. Seedlings with 2 or 3 wax layers were much better protected than seedlings with 1 wax layer. Hence, there was a clear threshold in effect between 0.6 and 1.0 mm of wax thickness (1 and 2 layers). This observation was considered in the development of the wax protection method.
Wax degradation should be slow, as the need of a long protection period of the seedlings puts emphasis on a slow degradation rate of the wax in the air and especially in the soil. The pine weevils can penetrate the top soil and feed on the root neck. Feeding and girdling at this part would soon result in a dead seedling. To ensure a good protection of this part of the seedling, a low degradation rate of the wax coating on the root neck and the stem base is needed. The wax degradation in soil was tested, by burying wax bars in moist soil in darkness at 8 oC and 20 oC. The degradation rate was temperature dependent, being very slow at 8 oC but increasing more than 10 times at 20 oC.
The wax degradation in a culture of microorganisms was studied with an “OECD test for inherent biodegradability, test 302b” and the wax degradation was compared with the more familiar and similar substances, paraffin and beeswax. The medium was a mixture of mineral nutrient, activated sludge and microorganisms and the decomposition was measured by the consumption of oxygen or the production of carbon dioxide. The wax degradation was measured with two different equipments, one in the Norsk Wax laboratory and the other at the University of Oslo. In the beginning of the process the degradation rates were fast with beeswax as the fastest one and wax (Bugwax type C) was the slowest. Both methods for the measurements of degradation showed a slow degradation of the wax, which is important when the wax should be a stable protection against pine weevils for two years.
Effect of the wax on the environment since small pieces of the wax cover can fall down to the soil surface in the forest. The wax pieces may affect the soil fauna and a test method “OECD Guidelines for Testing Chemicals, Collembolan reproduction test in soil” with collembolans (springtail) as model test system was used. The springtails (Folsomia quadrioculata) were sampled in a spruce forest near to Oslo and the animals were reared in the laboratory at 15 oC. Two experiments were conducted, one with two different amounts of wax pieces and another with drought stress and the highest amount of wax. The highest concentration of wax was several times higher than the highest recommended in the OECD guidelines. After 14 and 28 days no significant difference was found between the number of adults and juvenile animals in control soil and soils with wax pieces. The results indicate that the wax protection method is an environmentally friendly method.
A field trial in the Southwestern part of Norway was conducted for testing the wax method in a coast field with rough weather conditions and a large population of pine weevils. The results showed a close relationship between the wax height, wax thickness and an effective protection of the seedlings for two summer seasons and one winter.
The field experiment was conducted in 2013 and 2014 in coastal forest with a large population of pine weevils. The hillside was steep and soil scarification in this area was not possible. The examination in October 2013 showed the pine weevil problem in this area. 83% of the control seedlings were damaged after weevil attacks and 21% of the control seedlings were killed by the pine weevil feeding. The wax treatment protected the seedlings and when the plants were treated with 15 cm wax height and 1.4 mm thick wax layer only 17% of seedlings were attacked by pine weevil. The amount of cracks in the wax was important for wax protection quality, and increasing the wax thickness from 1 mm to 1.4mm decreased the amount of cracking. In October 2013 wax cracks were found in 53% of the seedling with 1 mm thick wax, while only 15% of the seedlings with 1.4 mm thick wax had cracks in the wax. The problem with the pine weevil can increase in the summer the second year. The adult insects laid eggs in the roots of the stumps the first summer and the next summer both the old and a new generation of pine weevils will feed on the seedlings. In August 2014 the examination of the field showed that 46% of the control seedlings were dead and 42% of the control seedlings were still alive, but seriously injured. The waxed seedlings were still protected by the wax treatment, and 15 cm wax height and 1.4 mm wax thickness gave the best protection. Some of these seedlings were not attacked by the pine weevils at all and the wax cracking area was low.
The effectiveness against pine weevil damage by wax coating of seedlings conducted with the machine developed by the Weevil STOP project was evaluated by SLU after conducting two controlled field tests in 2014 and 2015. For the first test seedlings treated in May 2014 at Electrozeta in Italy were used while for the second test the seedlings had been treated with the improved machine at Plantex in Estonia in February 2015. In addition, the performance of wax coated seedlings treated in Estonia 2015 was assessed in practical forest plantations. These evaluations showed promising results with relatively good protection against pine weevil damage.
A comparison of the two controlled field tests (started in 2014 and 2015) showed about the same proportion of seedlings attacked by pine weevil: around 20% of the wax treated seedlings and between 50% (2014) to 60% (2015) of the control seedlings. An equal proportion (around 30%) of control seedlings was also killed by pine weevil feeding in both tests. However, a higher proportion of wax treated seedlings was killed by pine weevil in 2014 (4.1%) than in 2015 (1.3%). Hence, the protective effect of the treatment appears to have improved.
The proportion of seedlings killed by drought was highest in the field test started in 2014: 13% of the wax treated and 6% of the seedlings treated with Merit Forest WG (imidaclopride; the insecticide used as control). In the field test started in 2015 only 3% of the wax treated seedlings and less than 1% of the insecticide treated seedlings were considered as being killed by drought. This difference may have been due to that it fell less rain and the temperature was higher in July 2014, i.e. during the critical period when the root system is getting established. Other causes could be different plant material, timing of the wax treatment or improved waxing conditions in Estonia 2015 compared to Italy 2014.
Inventories of practical plantations of wax treated seedlings showed that the total mortality was fairly low (range 4-21%) and the mortality due to pine weevil feeding was in average only 4%. The percentage of seedlings considered as being killed by drought was also relatively low (4%). When comparing sites with or without soil scarification the seedling mortality due to pine weevil feeding were overall lower on sites with soil scarification.
Economic validation of the Weevil STOP seedlings and waxing system
The cost of a planted seedling
The cost of producing a seedling and planting it in the forest differs from one country to another. It is cheaper in a low cost country e.g. in the Baltic and more expensive in a high cost country in Scandinavia.
Seedlings are also commodity products that travel across country borders.
In Norway the cost of a one year old containerized seedling is NOK 2.00 (0.21 EUR). The additional cost for planting it in the forest is typically around NOK 2.50 (0.27 EUR). Thus a lost seedling in the forest represents a cost of NOK 2.00 plus NOK 2.50 that is a total of NOK 4.50 (0.49 EUR).
The cost of treating the seedling with insecticide is NOK 0.25 (0.027 EUR).
If there is soil scarification before planting there is an additional cost of NOK 1.00 (0.10 EUR) per plant.
The total economic validation of the loss of a seedling is higher than the planting costs if the reduction of growth (lost production of wood) is included in the calculation, and even higher if the value of the loss for the wood processing industry is taken into account.
For the forest owner the most relevant loss is the cost of replanting each seedling lost to the pine weevil, and this is approximately 0.49 EUR.
If the wax coating protects the seedling from damage and increases the survival rate of the planted seedlings this is an economic benefit for the forest owner.
The cost of the developed Weevil STOP technology (the wax coating application)
The cost of the application equipment developed in the project will depend on the level of automatization. In the basic unit the seedlings are loaded manually from the trays into the cups on the machine and the waxed, cooled seedlings are picked out manually for packing.
Auxiliary equipment, such as a pick and place unit to load the cups automatically with seedlings from the trays and a packing line for the waxed seedlings, can be added to the basic unit.
Based on the practical experiences at Plantex nursery in Estonia running the pilot machine, the total cost is estimated assuming that each worker is loading 1300 plants per hour or packing 1300 per hour. The capacity of the machine is then 3900 plants per hour with 3 persons loading and 3 people packing plants. A part of the job for this group of 6 people is also to load the machine with wax and clean the filters in the machine during operation. In order to increase the production speed, it is estimated that the machine can operate at 5200 seedlings per hour when 4 people are loading and 4 packing. A fully automatic machine will strongly reduce the need for manual workers.
The cost for wax treating 1000 containerized spruce seedlings is below 50 EUR when the machine is loaded manually.
Profitability
The cost of protecting the plant with wax or insecticide compared to losses by not protecting it
A wax coated plant in the forest has a cost of 0.54 EUR compared to the cost of the unprotected plant which is 0.49 EUR. The cost of an insecticide treated plant in the forest is 0.52 EUR.
If we assume that the number of lost plants is 600 plants out of 1000 planted, the economic loss is 294 EUR per 1000 plants. If the plantation density is 2200 plants per hectare the loss becomes 647 EUR per hectare. If we wax coat the plants and achieve a reduction of damages to 200 plants out of the 1000 planted, the economic loss is 50 EUR for the wax cost of 1000 plants (110 EUR per hectare) plus the value of the 200 plants lost (98 EUR), in total 148 EUR per 1000 plants. Then the loss is reduced to 325 EUR per hectare.
The saving becomes the difference of 322 EUR per hectare planted.
Because the protection rate varies with the local conditions such as the micro and macro climate, water access, soil conditions and weevil population the success as a weevil protection measure of the wax coating will vary.
In the case described above, where we planted 2200 seedlings per hectar, thecost for the wax treatment is always recovered if the loss is reduced with 10% compared to the untreated seedlings. If the wax gives 5% better survival compared to insecticide there is an economic benefit to use wax instead of insecticide.
The total cost
The total cost following damages to new plantations must include the loss of produced wood. However, the economic loss for the wood industry following reduced growth of wood is outside of the scope for this project.
The wax coating adds a cost of 110 EUR per hectare planted. It is clear that this cost is recovered if the wax increases the survival rate of the seedlings with 10%. If the survival rate is increased by more than 10 % there is an economic gain for the forest owner.
In re-forestation it is often the practice to plant 20% more plants than required for optimal wood production.
This implies that even with a loss of 20% of the seedlings it is not necessary to start the cumbersome procedure of replanting.
Because of the large variations in the local populations of the great pine weevil the scale of the damage can vary from 0 to 100% dead seedlings.
The target is to keep the damages below 20% to avoid the need for re-plantation due to seedling loss. Only by protecting the seedling from the great pine weevil is this possible to achieve. The wax coating provides protection of the seedlings against pine weevil feeding.
However, using a combination of alternative measures such as soil scarification, plants with coarser stem and a coating of wax it is possible to get closer to this goal in practical forest planting.
Based on the principle of having predictable weevil populations and the possibility for risk evaluation, the amount of wax used on the seedlings can be reduced when the weevil problem is expected to be low and increased when the population is high in order to give the acquired protection.
Conclusion
The cost of the wax treatment varies with the size of the seedlings because a large seedling uses more wax than a small seedling.
The cost of applying wax to protect container grown spruce seedlings has been determined based on the experience from operating the pilot machine, developed by the project in an Estonian nursery in 2015. Running at a capacity of 3900 seedlings per hour in a semi- automatic mode, with manual loading and packing, it is possible to grade, wax and pack 1000 seedlings with an additional cost of 50 EUR. This equals an additional cost of 110 EUR per hectare planted compared to untreated plants.
If it is assumed that the cost of planting one hectare in Scandinavia is near to 1000 EUR annually, the wax coating becomes economically beneficial when the loss is reduced by 10% compared to untreated plants. Wax is also economically favourable to insecticide if 5% more plants survive with wax protection compared to insecticide treated. Both of these requirements are within technical reach for the wax method in Scandinavia.
Potential Impact:
The results from the Weevil STOP project will support the use of more wax for protecting seedlings from the pine weevils.
There are already nurseries utilizing wax as there is a request from forest professionals to plant without the use of insecticides, and wax is one alternative for this. An important result is that the enhanced knowledge gained from the Weevil STOP project will be helpful to ensure the correct use of the wax in the nurseries. We have learned that controlled waxing and controlled cooling are integral parts of the technology. As with all new technologies being introduced, to people who are unfamiliar with wax, it is important that a system for training and learning the technology is put in place. It will be important to train the local advisory service in countries where the wax method is planned to be used. The scientific results will be of good help in this.
Because the wax method requires only low-cost equipment it is an attractive method for small nurseries. However medium large to large scale nurseries can now also take the method in use because the machine developed has proved to apply the wax correctly on the seedlings with the required speed. The impact of this is that a Norwegian nursery is planning to have one machine built for installation in May 2016.
One of the most important meeting places for new technologies is at the forest trade fares.
Here many professionals are present and there can be direct communication between users and the Weevil STOP project. The most important of the forest trade fares is Elmia Wood in Sweden.
Participation at this event for the first time in 2013 was very successful for the dissemination of the project since the wax method was highlighted in the press releases from this occasion.
The developed wax machine could only be presented to the public for the first time in June 2015 at Skogs Elmia due the IPR situation and ongoing patent application.
Another important place for dissemination has been at professional meetings. In 2014 at the yearly Norwegian ”Skog og Tre” Conference, there was an opportunity to present the available scientific results after the first period of the project. In addition, the researchers from the University of Oslo has initiated several forest trials with wax in Norway where it has been possible to gather many forest people to observe the performance of wax protected seedlings in practical plantations in south of Norway.
Similar arrangements where forest professionals can see the waxed seedlings in practical plantations have been arranged with success in Latvia and Estonia by the Latvian Forest Owner’s Association and the Estonia Forest Union respectively.
The exact registration of forest trials done by the researchers from the Swedish University of Agricultural Sciences will be used at upcoming occasions within the forest industry.
The CEPF (Confederation Europeenne des Proprietaires Forrestiers) has presented the project on several occasions, and at the “members day” in December 2014 in Brussels the project had the opportunity to have a table where information was distributed.
A broader coverage of the ongoing project was assured by an article in Norway’s largest newspaper Aftenposten in 2012 and an article in the magazine International Innovation in 2015. Both of these publications are also read by people outside of the forest industry, but with an interest for new technologies.
There have been several articles describing the project in professional magazines at national levels in Sweden, Estonia, Latvia and Norway. The consortium members have also been active in presenting the activities and goals in relevant meetings at a national level.
In October 2015 the University of Oslo had a poster presentation at the international conference for Biopesticides in Swansea, Wales.
The homepage www.weevilstop.com presents an opportunity to disseminate the project results. This home page will be updated with relevant information the first year after the end of the project.
Exploitation of foreground: Tree planting and re-forestation are very important tasks in order to secure access to wood as a raw material for the forest-based industries. Wood is the highest cost for many of these industries and the growing demand for renewable energy continues to increase competition for wood. It is therefore very important to promote and secure domestic supply of the wood raw material.
The results of the Weevil STOP project are of interest for forest businesses all over Europe because it contributes to a new practice for reforestation of conifer species without the use of insecticides. The project has developed a machine that can apply the molten wax onto the lower parts of conifer seedlings in order to form a protective layer against feeding pine weevils.
Biological studies performed on spruce seedlings coated with wax at various stages of the winter storage cycles has revealed knowledge that can be used to establish good practical routines for wax protection in a forest nursery. Laboratory studies with pine weevils and forest trials have taught us how to achieve the best protective function of wax.
In addition, field trials in the project showed that the final test of the machine in a nursery produced seedling that were relatively well protected from feeding pine weevils.
The machine developed will be of particular interest for the small to medium sized nurseries producing containerized seedlings due to the technical simplicity and moderate cost level compared to other protective coating systems for forest seedlings.
The project results will also support the use of wax as weevil protection on bare rooted conifer seedlings. This type of seedling production is more common in Europe outside Scandinavia.
The Weevil STOP project has enhanced the level of innovation and exploitation of technology in order to improve the best-practice of pest management in the forest sector during plantation for re-forestation.
The Weevil STOP project will help the forest sector to implement the new EU directive on Sustainable use of Pesticides (2009/128/EC), which restricts the use of insecticides due to health and environmental issues, and demands integrated pest management with priority given to non-chemical methods of plant protection.
The Weevil STOP project will help the forest sector to implement the EU Council Directive (EC No 1698/2005) and (EC No 74/2009) on support of rural development that demands proper water management and the protection of water quality. Currently used insecticides have strong negative impact on life in aquatic systems, insects (focus on bees) and birds, as well as human health.
The Weevil STOP project will help the forest sector to implement international and European standards on certified wood products such as FCS or PEFC and will help to meet the demand for certified wood products.
The Weevil STOP project will help the forestry sector to implement EU’s Forestry Strategy and Forestry Action Plan which demands the introduction of integrated pest management and sustainable forest management.
Professional forest organizations and the general public may have different views regarding what is the positive outcome of our research and innovation work. People and organizations making a living from harvesting forest, will usually first look at the economic benefits of the new alternative methods in a short term perspective. The public that use the forest for recreational purposes are more concerned that the techniques used in forestry are acceptable for other reasons than only the economical and want sustainable and environmentally friendly methods for the future.
The use of barrier coatings like wax or water born polymers represents an alternative to the European tradition of continuously designing new chemicals for regulating the behaviour of nature.
The results show that the use of insecticides may be replaced in many cases with a wax coated seedling. Our results from the Weevil STOP project can be used to change forest practice in the direction of reduced use of chemical insecticides because it offers a solution to the pine weevil problem in many cases where there used to be no environmentally friendly alternatives.
This wax coating is shown to be biodegradable, non-toxic and un-harmful to the environment and organisms living there. Unlike many water based coatings the wax does not contain any fungicide.
In the modern world it is now possible to re-think the strategies and find that the use of an inert wax
formula in combination with appropriate forest practice will lead to successful re-forestation and reduce the need for dangerous insecticides.
Forest is a conservative business that only slowly adopts new technologies. Although wax has been in use at a few nurseries in Sweden for some time already, the possibilities and the limits of this technology must be better understood. One aspect is that the forest seedlings are grown in different production systems, and this will result in plants of various size and shapes.
Because forestry without use of insecticides imply many practical and technological challenges for the nursery there is a need for information about how to make these changes in real life. Change of technology creates uncertainty for the nursery and reluctance for this reason may slow down the process of leaving the tradition of insecticides. The Weevil STOP project has created a solid scientific documentation that can be used to communicate how the growth of the seedling will be influenced by the wax and to establish correct procedures in the nurseries. To achieve a rapid commercialization of the method, equipment for the nurseries is critical in order to be able to treat the large number of seedlings necessary and to avoid incorrect performance of the wax method.
Besides this very practical need to produce non-chemically treated seedlings in the nurseries, it will also be necessary to provide information about the benefits of this method to a larger audience of forest owners to achieve market willingness and motivation to buy the wax coated seedlings.
The scientific understanding established in the project will give valuable support to establish wax coating as an alternative to insecticides for containerized seedlings. The reach of the enhanced knowledge is also beneficial for the use of wax protection on bare-rooted, non-containerized grown conifer seedlings.
A successful machine construction for automatic waxing of seedlings grown in containers is a commercial product needed in the nurseries because there has been no such machine available in the market until today. The results from the pilot machine in this project will establish new principles for automatically waxing seedlings and the base for constructing a fully automatic production line.
The market is offered several alternatives to insecticides today and there is uncertainty regarding what the future will look like.
Due to this it is not possible today to give an exact number of nurseries that will select this machine construction. However, it is positive that the largest nursey in Norway is installing a new machine built on the developed concept in spring 2016.
It is assumed that the wax method can get a market share of 25% of the total European market for protected seedlings without separating between containerized and non-containerized conifers.
Traditionally 40% of the 1010 million seedlings planted in EU-27 have been protected with insecticides. In the future market without insecticides several substitutes will be available such as coatings of acrylics, acrylics and sand, other coatings, collars and wax. If we assume that wax will take a 25% market share this means that 100 million seedlings will be wax treated each year in the EU.
Scientific articles: A large number of scientific measurements have been performed in the Weevil STOP project and the processing of the data gives new information of interest for the scientific community as well as for the practical use of wax on living plants. Most of the scientific results were available only toward the end of the project period. For this reason all the scientific papers will only be published after the project has been closed in October 2015.
The following scientific articles are in progress or planned based on the research work done at the University of Oslo and the Swedish University of Agricultural Sciences and their associates for the project Weevil STOP.
"Protection of conifer seedlings by wax coating: Effects on pine weevil feeding damage, seedling survival and growth"
Authors: A.V. Vollsnes, P. Öhrn, A.B. Eriksen, G. Nordlander
"Absorption and fluorescence spectra from conifer needles using array spectrophotometers"
Authors: A. V. Vollsnes, T. B. Melø
"Effects of heat on Norway spruce seedlings"
Authors: A. V. Vollsnes, T. B. Melø, A. B. Eriksen
"X-ray micro computerized tomography uncovers Norway spruce seedlings root development"
Authors: A. V. Vollsnes, B. Atkinson, C. Sturrock
"Norway spruce seedling establishment after manipulations of needles on lower stem"
Authors: A. V. Vollsnes, B. Atkinson, C. Sturrock, A. B. Eriksen
"An insecticide-free protection against pine weevil feeding on seedlings of a coastal conifer forest"
Forfattere: A. B. Eriksen, A. V. Vollsnes
List of Websites:
Project web site: www.weevilstop.com
Further information can be obtained from contacting
Jarl Markus Pettersen, Norsk Wax AS, Tel: +47 90530004, e-mail: jmp@norsk-wax.no
The large pine weevil (Hylobius abietis) is the most destructive pest in re-forestation of conifer forest across Europe, Russia and Asia. If the planted seedlings are not protected against the insect, costs in the range of 140 million EUR a year for the forest industry and society may be the consequence in EU-27. The use of highly toxic insecticides has been the practice for many years to suppress the pine weevil problem. The EU aims to substitute the insecticides with non-chemical methods. The Weevil STOP project, running for 3 years from October 2012, worked on enhancing the knowledge of substituting the insecticides with wax as mechanical protection and developed a machine to apply the wax on each individual seedling in the nursery.
Researchers from the University of Oslo studied the effect of wax thickness and heights and found that the plant fitness and shoot production was good as long as the wax coating was less than two thirds of the seedling height. A number of waxing tests showed the importance of wax temperature control and particularly rapid cooling after the wax application.
The importance of sufficient wax thickness was shown in a growth experiment where the stem diameter increased more than 200 %. Here a wax layer initially about 1.5 mm thick showed a low cracking tendency while thinner layers showed cracking.
Degradation tests on wax in soil showed that the degradation rate was low in cold soil (8 oC) and significantly higher in warmer soil (20 oC). A biodegradation test (OECD) showed that the wax used biodegrades slower than beeswax but that the wax was biodegradable.
Researchers from Swedish University of Agricultural Sciences found in laboratory experiments that the protective effect of wax treatment is affected by wax thickness. The performance of the wax coating increased with the thickness of the wax layer. The results showed a threshold in protective effectiveness between 0.6 mm and 1.0 mm wax thickness. The protective effect of wax treatment was also investigated in two controlled field tests (in 2014 and 2015) and in practical forest plantations (2015). In the two controlled field tests a lower proportion of wax treated seedlings were killed by pine weevils in 2015 (1.3%) than in 2014 (4.1%), while equal proportions (approx. 30%) of control seedlings were killed by pine weevils.
In the field test started in 2015 only 3% of the wax treated seedlings and less than 1% of the Merit Forest seedlings were considered as killed by drought. The inventories of practical plantations showed low seedling mortality for wax treated seedlings, both regarding mortality caused by pine weevil feeding (4%) and by drought (4%).
A prototype machine was constructed by the institutes Teknologisk Institutt from Norway and Labor from Italy. This machine was placed in a nursery in Estonia. More than 200,000seedlings where wax treated in January 2015. A large portion of these seedlings were used in field trials and practical plantations in Sweden with the results describe above.
The capacity requirement for wax treatment was 60 seedlings per minute in the nursery and in shorter periods the machine tested 50% above this requirement. The waxing and cooling procedure allowed the seedling to be packed within 2 minutes after treatment.
Based on the experiences from the nursery in Estonia the treatment cost is below
0.05 EUR per seedling
Project Context and Objectives:
The large pine weevil (Hylobius abietis), a small insect the size of a fingernail, is the most destructive pest in tree planting and re-forestation of conifer forest across Europe, Russia and Asia in terms of economic damage caused.
This insect is often present when planting after clear-cutting because it is attracted to the area by volatile compounds released from the stumps, and it will breed in the stumps for some years.
If the planted seedlings are not protected against this insect, costs in the range of € 140 million a year for the forest industry and society may be the consequence in EU-27.
Re-forestation practice has for many years been depending on using highly hazardous insecticides to suppress the large pine weevil problem.
The insecticides are often highly toxic for both animals and humans and the EU aims to substitute the insecticides with non-chemical methods. Non-chemical methods means alternative methods to chemical insecticides based on forest techniques and/or physical or biological pest control methods.
Our project has developed an environmentally friendly, cost efficient, non-chemical pest control method against the large pine weevil. It is a physical plant protection based on a highly refined wax formulation that is applied once on the main stem of conifer seedlings in the forest tree nursery before the seedlings are distributed for planting in the forest. Correctly performed the protection from wax will last for two years, which is the most critical time period for pine weevil attacks.
The EU-27, represented with 158 million ha of productive forest, is the sixth largest forest area in the world with an annual increase of almost 0.5 million ha due to intensive forestation and re-forestation activities.
Coniferous species cover 45% of total productive forest areas in EU-27. In 2011 alone approximately 1010 million coniferous seedlings (mostly pine and spruce) were planted. Of these 40% were treated with insecticides as protection against the pine weevil.
Tree planting and re-forestation is a very important part of Sustainable Forestry Management and essential for securing access to wood as a raw material for forest-based industries. A competitive forestry output enhances the competitiveness of the industry. Forest protection against pests is an integral part to achieving strong competitiveness over time.
The European forestry and forest-based industries provides more than 3.5 million jobs, many of them in rural areas where people have limited job opportunities.
The Weevil STOP project addresses the need of the European Private Forest Owners Community which has almost 16 million private forest owners, most of them being SMEs’.
The private forest owners manage approximately 60% of Europe’s forests with an average forest size of 13 ha.
The large community of Private Forest Owners is threatened with significant economic loss due to the prohibition of hazardous chemicals as plant protection products, and face great challenges to meet the new EU Directive on Sustainable use of Pesticides (2009/128/EC), which requests the implementation of integrated pest management and that priority is given to alternative non-chemical methods of plant protection.
A proactive approach to prepare for forest practice without insecticides was taken by some SME-AGs of Private Forest Owners from Norway, Sweden, Estonia, Latvia and CEPF in Brussels in order to launch this trans-national project plan for Weevil STOP in 2012.
Several SMEs working in the forest sector in the Nordic countries joined in and formed the consortium, including also a machine builder from Italy and a specialized wax supplier from Norway.
The overall technological aim of this project was to develop an automated process for the precise covering of the main stem of conifer seedlings (1 and 1.5 year old conifer seedlings) with a highly refined wax that provides mechanical protection against the pine weevil. The technical solutions had to be robust and reliable as well as economically cost efficient, in order to work in the nursery environment.
A developed gripping and picking machine based on modern robotic technologies was to be used to pick out seedlings from all kind of plant containers and placing them into single holders. A novel wax application process was to be developed to be able to apply the melted wax precise on the lower part of the main stem (the machine task given to Teknologisk Institutt from Norway and Labor S.R.L. from Italy).
More specifically this task involved developing a wax application process that applied wax on the seedlings main stem and less on branches, coated maximum 60% of the stem length from its base and upwards, and applied a layer of wax with thickness above 0.6 mm, preferably in the range 1.0 to 1.5 mm, on the stem.
The minimum capacity for the machine was set to 60 seedlings per minute, which equals an annual capacity of 2.3 million seedlings (season: 80 working days with 8 hours per day). The method should be scalable to an annual capacity of up to 18 million seedlings per year.
To make the system economically within reach for smaller nurseries the target investment cost should be close to 100,000 € for a basic unit and the treatment cost for 1000 seedlings maximum
50 €.
The scientific objectives of the Weevil STOP project were to gain advanced knowledge regarding the use of wax on young seedlings by studying wax-plant interactions and testing seedling quality (at the University of Oslo), investigate wax-weevil interactions and testing the protective function of the wax (at the Swedish University of Agricultural Sciences).
One of the main scientific objectives of the Weevil STOP project was to identify the wax coating specifications needed to achieve an optimal protection of the spruce seedlings against pine weevil attacks for 2 years, two summers and one winter season. Two of the main factors would be ensuring high plant fitness and good wax cracking resistance, making the wax stretch in accordance with the increasing stem thickness of growing plants without cracking. By using several wax cover heights, wax thicknesses and plant sizes the best specifications for wax coating were to be found. Further, the possibility of extending the period of applying wax on the seedlings in the nurseries was to be studied. If the period could be extended, the capacity of a single nursery to produce wax coated seedlings would be increased. Finally, the degradation of the wax was to be studied, to ensure that it would not degrade before the two-year protection period was completed and to investigate the biodegradability of the wax.
The overall performance of the developed system for protective function of wax towards feeding pine weevils should finally be evaluated in comparative field trials and in practical forest plantations.
Project Results:
The development of the waxing machine
Concept of layout: The main elements of the machine are a pick and place unit, a conveyor belt loop system integrated with a screw transporter, a novel wax shower unit and a heated reservoir for the wax. The seedlings are removed from the trays by the pick and place unit in series of 9 seedlings and placed in individual cups. These cups are then transported on a conveyor belt to the waxing area. In the waxing unit the cups holding the seedlings are turned 80 degrees into a close to horizontal position, and at the same time moved forward by a rotating screw. A friction device forces the cups holding the seedlings to rotate while passing the waxing unit. During these movements, the seedlings are coated with wax from the root neck and 10-14 cm up, by several wax showers positioned above the route of travel. Immediately after the wax treatment the seedlings are cooled down by a cold water shower, and finally excess water is removed by forceful cold airstreams.
The pilot machine has been designed for containerized spruce seedlings, grown in system trays, and with a height between 15 and 28 cm above root neck. The pick and place unit has a limitation concerning seedling height, given by these criteria. In a new machine it is possible to design the pick and place gripers for handling higher seedlings. In the pilot machine, seedlings larger than 28 cm and up to a height of 40 cm above root neck could only be manually loaded into the cups.
The transport system has been designed to transport large volumes of conifer seedlings through the wax applicatıon unit and at the same time avoiding that wax and dirt enter the moving parts and cause malfunction. To manage these requirements, the project used
1) a transplantıng machine modified to be stronger than ordinary trans-planter machines for greeneries but modified for conifer nurseries
2) a contınuous conveyor system that was easy to clean for soil and spillages
3) an innovative spiral transporter was developed for transporting the cups through the waxing unit. This construction was able to turn the plants into a nearly horizontal position before entering the wax unit and rotate them through the waxing and the cooling units
4) a special cup design in aluminium was developed to hold the plants both in the vertical position as well as in the nearly horizontal position. These cups should be designed especially for the containers used in the nursery to ensure correct positioning of the seedling in the machine. The pilot machine used 200 of these cups which were loaded either manually or with the pick and place unit. The seedlings were manually picked from the cups after the waxing process.
The major challenges in the designing of the wax application system for conifer seedlings were related to the nature of the wax itself and the loose soil from the seedlings. The state of the wax changes from liquid to solid material within a few degrees of cooling. This behaviour easily creates build up of unwanted wax deposits in the machine. The seedlings have a tendency to create soil spillage from the root balls and also lose some needles. Together with the wax these deposits may increase the problems of keeping a machine running regularly. It was important to keep the liquid wax away from moving machine parts.
The wax melting unit (wax tub) was a central part of the machine. The unit was designed to have sufficient melting /heating capacity in order to feed the wax shower arrangement in use. A filter system was integrated on the top of the melting unit to prevent soil, needles and root parts from entering into the wax reservoir. These filters were easy to remove for cleaning of accumulated dirt. It was necessary to keep the wax in circulation in the melting pot when it was melted. The wax formulation contains a white pigment that has a higher density than wax and thus will precipitate out of the wax if it is not continuously stirred. To maintain the circulation two centrifugal pumps were used to circulate the fluid wax when it was kept at the 82 degrees Celsius operating temperature. These pumps would also operate the wax showers. The wax tub was constructed with two chambers, a “clean-wax” and a “dirty-wax” chamber. During operation with seedlings in the cups, the fluid wax was kept clean from the contamination of soil by several filters and sieves in the melting unit.
The liquid wax was applied from above at low pressure by means of a custom made shower system. This design can be adjusted to any seedling height by simply changing the perforated steel plates in the shower heads. The pilot machine had 2 shower heads, each with 4 individual showers, thus there were 8 showers available for each seedling passing the waxing area. The shower heads were placed approx. 1 meter from each other and in between there was a cold air fan to cool the first wax layer.
The wax layer on the seedling could be controlled by the number of showers being used and their positions along the screw transporter. In most cases a sufficient wax layer was achieved using 3 or 4 of the showers, keeping the others in closed position.
It was important to bring the temperature down to below 40 degrees Celsius immediately after the waxing process. The most efficient cooling of waxed seedlings is obtained by water showers. Controlled water cooling was possible with water showers when the seedlings were still nearly horizontal and rotating while moving along the spiral screw.
The pilot machine had a water reservoir with a pump that supplied 4 shower heads with cold water. This arrangement reduced the wax temperature to below 40 degrees Celsius within seconds after the wax application. At the end of the conveyor screw the cups and seedlings were repositioned to vertical angle and entered a cooling tunnel with cold air in order to reduce the temperature to below 20 degrees Celsius.
During the waxing season (winter) the indoor temperature at nurseries is low at around 5 degrees Celsius. Therefor the cooling water stays cold and there is sufficient cold air available for the cooling tunnel. In milder surroundings cooling units can be installed for the water and the air.
The prototype waxing machine was assembled at a workshop in Italy and started for the first time in February 2014. Following this there were several improvements done to the machine to ensure that it would operate well in the final testing in an appropriate nursery surrounding in a Nordic country. In particular it was necessary to adjust the cooling sequence and install the intermediate cooling unit. When running at higher speeds it was clear that the feeding system of the cups had to be synchronized with the pick and place unit. The machine was further optimized and tested for speed and synchronization in Italy in autumn 2014. It was moved to Plantex nursery in Estonia for testing in an appropriate industrial environment at the end of 2014. More than 200,000 seedlings were waxed with this machine during the test in Estonia in January and February 2015.
Already in May 2014 the first 1000 seedlings were wax-treated for long-term tests in Sweden and Norway. At this point the water cooling unit was not installed and only manual cooling in a bucket of water was used. Before moving the machine to Estonia a cooling unit was installed employing water showers and cold air. With this appropriate cooling unit in place approximately 200.000 seedlings were wax-treated in January 2015 at the Estonian nursery. These were used in forest trials and practical plantations in Sweden spring 2015, together with insecticide treated (Merit forest) and control seedling without weevil protection. The final machine was tested according to the objectives in the project determined at the beginning of the project. The wax application on the seedlings was correct regarding placement, thickness and quality. The capacity of the machine was 60 seedlings/minute and the waxing unit alone (without using the pick and place unit) exceeded this requirement by 50% in shorter periods. The cooling and drying of the plants after waxing was sufficient to pack the plants approximately 2 minutes after treatment. The Pick and place unit had limitations regarding plant size and velocity, and was quite complex to operate.
The tray system for growing the seedlings was different at the Plantex nursey in Estonia than the tray system used during the construction period of the machine. For this reason only the basic wax unit was moved to Estonia and the cups were loaded manually.
At the nursery in Estonia the machine proved to be robust and have capacity for high-volume production in an industrial environment.
From the experiences of operating the machine in the nursery environment, the technical manager in the Weevil STOP project and the institutes made a list of recommendation for the next generation of the pilot machine. Because the machine produced seedlings that tested well, the main principles and functions are recommended to be used in next machine. The improvements recommended are stronger materials for more robustness, simplify some details to improve cost efficiency, and change suppliers for better/cheaper components. Also it was recommended to offer to the market a basic semiautomatic machine with manual loading and discharging of the cups. An additional option is then to add a pick-and-place unit to feed the cups automatically from the trays.
For the machine construction and principles for waxing and cooling a European PTC patent application has been filed in Italy by Mr. Guerrino Zannier from Weevil STOP partner Electrozeta, the machine builder in the consortium. The submission date was 21st May 2015 and the patent application has the Italian application no 102015000016675.
Testing of the impact of the waxing process on plant quality of seedlings from the field and freeze storage during the winter, spring and early summer have shown the importance of controlled wax temperature and rapid cooling process after the wax application. Long-term (months) growth experiments with seedlings wax treated as recommended, showed no differences between the controls and the waxed plants in top shoot heights and side shoot growth. The waxing process gave a good protection quality of the wax against pine weevil attack and allowed a greater flexibility in the timing of wax treatment of the seedlings since the waxing can be conducted from December to July.
Unsatisfactory cooling of the wax can give wilting symptoms after six to eight weeks after planting in the field.
These results indicated that the wilting problem with waxed spruce seedling in field trials can be an effect of an unsatisfactory cooling process. A wax guidance explaining the waxing process has been made and is recommended (A. B. Eriksen and A. Vollsnes, 2015).
The effects of wax thickness and heights on the stem of the Norway spruce seedlings on the growth and development were studied by short term (weeks) and long term (month) experiments under summer conditions in environmentally controlled growth rooms at the University of Oslo. A number of combinations of three plant sizes, three wax thicknesses and six wax coating heights up to 100% wax covering of the seedling were conducted to test the extreme limits for the wax treatments and the interactions between seedling and wax. Covering too high percentage of the green parts of the seedling, gave a short-term decrease of the growth production. The fitness and growth of the seedlings was good as long as the wax coating was less than two thirds of the shoot height. During a four-month growth experiment in growth rooms, the stem diameter increased up to 200% posing a great challenge to the wax plasticity. When the stem diameter increased, the wax coating was stretched and became thinner, increasing the cracking tendency, as a thin coating will crack easier than a thick. The seedlings should be protected against pine weevils for 2 years by the wax barrier even though the wax coating was stretched during that period. The thickness of the initial wax layer should endure 2 years stretching. A wax layer 1.5 mm thick, showed a low cracking tendency despite large stem diameter increase.
Wax – pine weevil interaction studied in laboratory tests at SLU showed that the thickness of the wax layer was a crucial factor with regard to its protective effect. Seedlings with 2 or 3 wax layers were much better protected than seedlings with 1 wax layer. Hence, there was a clear threshold in effect between 0.6 and 1.0 mm of wax thickness (1 and 2 layers). This observation was considered in the development of the wax protection method.
Wax degradation should be slow, as the need of a long protection period of the seedlings puts emphasis on a slow degradation rate of the wax in the air and especially in the soil. The pine weevils can penetrate the top soil and feed on the root neck. Feeding and girdling at this part would soon result in a dead seedling. To ensure a good protection of this part of the seedling, a low degradation rate of the wax coating on the root neck and the stem base is needed. The wax degradation in soil was tested, by burying wax bars in moist soil in darkness at 8 oC and 20 oC. The degradation rate was temperature dependent, being very slow at 8 oC but increasing more than 10 times at 20 oC.
The wax degradation in a culture of microorganisms was studied with an “OECD test for inherent biodegradability, test 302b” and the wax degradation was compared with the more familiar and similar substances, paraffin and beeswax. The medium was a mixture of mineral nutrient, activated sludge and microorganisms and the decomposition was measured by the consumption of oxygen or the production of carbon dioxide. The wax degradation was measured with two different equipments, one in the Norsk Wax laboratory and the other at the University of Oslo. In the beginning of the process the degradation rates were fast with beeswax as the fastest one and wax (Bugwax type C) was the slowest. Both methods for the measurements of degradation showed a slow degradation of the wax, which is important when the wax should be a stable protection against pine weevils for two years.
Effect of the wax on the environment since small pieces of the wax cover can fall down to the soil surface in the forest. The wax pieces may affect the soil fauna and a test method “OECD Guidelines for Testing Chemicals, Collembolan reproduction test in soil” with collembolans (springtail) as model test system was used. The springtails (Folsomia quadrioculata) were sampled in a spruce forest near to Oslo and the animals were reared in the laboratory at 15 oC. Two experiments were conducted, one with two different amounts of wax pieces and another with drought stress and the highest amount of wax. The highest concentration of wax was several times higher than the highest recommended in the OECD guidelines. After 14 and 28 days no significant difference was found between the number of adults and juvenile animals in control soil and soils with wax pieces. The results indicate that the wax protection method is an environmentally friendly method.
A field trial in the Southwestern part of Norway was conducted for testing the wax method in a coast field with rough weather conditions and a large population of pine weevils. The results showed a close relationship between the wax height, wax thickness and an effective protection of the seedlings for two summer seasons and one winter.
The field experiment was conducted in 2013 and 2014 in coastal forest with a large population of pine weevils. The hillside was steep and soil scarification in this area was not possible. The examination in October 2013 showed the pine weevil problem in this area. 83% of the control seedlings were damaged after weevil attacks and 21% of the control seedlings were killed by the pine weevil feeding. The wax treatment protected the seedlings and when the plants were treated with 15 cm wax height and 1.4 mm thick wax layer only 17% of seedlings were attacked by pine weevil. The amount of cracks in the wax was important for wax protection quality, and increasing the wax thickness from 1 mm to 1.4mm decreased the amount of cracking. In October 2013 wax cracks were found in 53% of the seedling with 1 mm thick wax, while only 15% of the seedlings with 1.4 mm thick wax had cracks in the wax. The problem with the pine weevil can increase in the summer the second year. The adult insects laid eggs in the roots of the stumps the first summer and the next summer both the old and a new generation of pine weevils will feed on the seedlings. In August 2014 the examination of the field showed that 46% of the control seedlings were dead and 42% of the control seedlings were still alive, but seriously injured. The waxed seedlings were still protected by the wax treatment, and 15 cm wax height and 1.4 mm wax thickness gave the best protection. Some of these seedlings were not attacked by the pine weevils at all and the wax cracking area was low.
The effectiveness against pine weevil damage by wax coating of seedlings conducted with the machine developed by the Weevil STOP project was evaluated by SLU after conducting two controlled field tests in 2014 and 2015. For the first test seedlings treated in May 2014 at Electrozeta in Italy were used while for the second test the seedlings had been treated with the improved machine at Plantex in Estonia in February 2015. In addition, the performance of wax coated seedlings treated in Estonia 2015 was assessed in practical forest plantations. These evaluations showed promising results with relatively good protection against pine weevil damage.
A comparison of the two controlled field tests (started in 2014 and 2015) showed about the same proportion of seedlings attacked by pine weevil: around 20% of the wax treated seedlings and between 50% (2014) to 60% (2015) of the control seedlings. An equal proportion (around 30%) of control seedlings was also killed by pine weevil feeding in both tests. However, a higher proportion of wax treated seedlings was killed by pine weevil in 2014 (4.1%) than in 2015 (1.3%). Hence, the protective effect of the treatment appears to have improved.
The proportion of seedlings killed by drought was highest in the field test started in 2014: 13% of the wax treated and 6% of the seedlings treated with Merit Forest WG (imidaclopride; the insecticide used as control). In the field test started in 2015 only 3% of the wax treated seedlings and less than 1% of the insecticide treated seedlings were considered as being killed by drought. This difference may have been due to that it fell less rain and the temperature was higher in July 2014, i.e. during the critical period when the root system is getting established. Other causes could be different plant material, timing of the wax treatment or improved waxing conditions in Estonia 2015 compared to Italy 2014.
Inventories of practical plantations of wax treated seedlings showed that the total mortality was fairly low (range 4-21%) and the mortality due to pine weevil feeding was in average only 4%. The percentage of seedlings considered as being killed by drought was also relatively low (4%). When comparing sites with or without soil scarification the seedling mortality due to pine weevil feeding were overall lower on sites with soil scarification.
Economic validation of the Weevil STOP seedlings and waxing system
The cost of a planted seedling
The cost of producing a seedling and planting it in the forest differs from one country to another. It is cheaper in a low cost country e.g. in the Baltic and more expensive in a high cost country in Scandinavia.
Seedlings are also commodity products that travel across country borders.
In Norway the cost of a one year old containerized seedling is NOK 2.00 (0.21 EUR). The additional cost for planting it in the forest is typically around NOK 2.50 (0.27 EUR). Thus a lost seedling in the forest represents a cost of NOK 2.00 plus NOK 2.50 that is a total of NOK 4.50 (0.49 EUR).
The cost of treating the seedling with insecticide is NOK 0.25 (0.027 EUR).
If there is soil scarification before planting there is an additional cost of NOK 1.00 (0.10 EUR) per plant.
The total economic validation of the loss of a seedling is higher than the planting costs if the reduction of growth (lost production of wood) is included in the calculation, and even higher if the value of the loss for the wood processing industry is taken into account.
For the forest owner the most relevant loss is the cost of replanting each seedling lost to the pine weevil, and this is approximately 0.49 EUR.
If the wax coating protects the seedling from damage and increases the survival rate of the planted seedlings this is an economic benefit for the forest owner.
The cost of the developed Weevil STOP technology (the wax coating application)
The cost of the application equipment developed in the project will depend on the level of automatization. In the basic unit the seedlings are loaded manually from the trays into the cups on the machine and the waxed, cooled seedlings are picked out manually for packing.
Auxiliary equipment, such as a pick and place unit to load the cups automatically with seedlings from the trays and a packing line for the waxed seedlings, can be added to the basic unit.
Based on the practical experiences at Plantex nursery in Estonia running the pilot machine, the total cost is estimated assuming that each worker is loading 1300 plants per hour or packing 1300 per hour. The capacity of the machine is then 3900 plants per hour with 3 persons loading and 3 people packing plants. A part of the job for this group of 6 people is also to load the machine with wax and clean the filters in the machine during operation. In order to increase the production speed, it is estimated that the machine can operate at 5200 seedlings per hour when 4 people are loading and 4 packing. A fully automatic machine will strongly reduce the need for manual workers.
The cost for wax treating 1000 containerized spruce seedlings is below 50 EUR when the machine is loaded manually.
Profitability
The cost of protecting the plant with wax or insecticide compared to losses by not protecting it
A wax coated plant in the forest has a cost of 0.54 EUR compared to the cost of the unprotected plant which is 0.49 EUR. The cost of an insecticide treated plant in the forest is 0.52 EUR.
If we assume that the number of lost plants is 600 plants out of 1000 planted, the economic loss is 294 EUR per 1000 plants. If the plantation density is 2200 plants per hectare the loss becomes 647 EUR per hectare. If we wax coat the plants and achieve a reduction of damages to 200 plants out of the 1000 planted, the economic loss is 50 EUR for the wax cost of 1000 plants (110 EUR per hectare) plus the value of the 200 plants lost (98 EUR), in total 148 EUR per 1000 plants. Then the loss is reduced to 325 EUR per hectare.
The saving becomes the difference of 322 EUR per hectare planted.
Because the protection rate varies with the local conditions such as the micro and macro climate, water access, soil conditions and weevil population the success as a weevil protection measure of the wax coating will vary.
In the case described above, where we planted 2200 seedlings per hectar, thecost for the wax treatment is always recovered if the loss is reduced with 10% compared to the untreated seedlings. If the wax gives 5% better survival compared to insecticide there is an economic benefit to use wax instead of insecticide.
The total cost
The total cost following damages to new plantations must include the loss of produced wood. However, the economic loss for the wood industry following reduced growth of wood is outside of the scope for this project.
The wax coating adds a cost of 110 EUR per hectare planted. It is clear that this cost is recovered if the wax increases the survival rate of the seedlings with 10%. If the survival rate is increased by more than 10 % there is an economic gain for the forest owner.
In re-forestation it is often the practice to plant 20% more plants than required for optimal wood production.
This implies that even with a loss of 20% of the seedlings it is not necessary to start the cumbersome procedure of replanting.
Because of the large variations in the local populations of the great pine weevil the scale of the damage can vary from 0 to 100% dead seedlings.
The target is to keep the damages below 20% to avoid the need for re-plantation due to seedling loss. Only by protecting the seedling from the great pine weevil is this possible to achieve. The wax coating provides protection of the seedlings against pine weevil feeding.
However, using a combination of alternative measures such as soil scarification, plants with coarser stem and a coating of wax it is possible to get closer to this goal in practical forest planting.
Based on the principle of having predictable weevil populations and the possibility for risk evaluation, the amount of wax used on the seedlings can be reduced when the weevil problem is expected to be low and increased when the population is high in order to give the acquired protection.
Conclusion
The cost of the wax treatment varies with the size of the seedlings because a large seedling uses more wax than a small seedling.
The cost of applying wax to protect container grown spruce seedlings has been determined based on the experience from operating the pilot machine, developed by the project in an Estonian nursery in 2015. Running at a capacity of 3900 seedlings per hour in a semi- automatic mode, with manual loading and packing, it is possible to grade, wax and pack 1000 seedlings with an additional cost of 50 EUR. This equals an additional cost of 110 EUR per hectare planted compared to untreated plants.
If it is assumed that the cost of planting one hectare in Scandinavia is near to 1000 EUR annually, the wax coating becomes economically beneficial when the loss is reduced by 10% compared to untreated plants. Wax is also economically favourable to insecticide if 5% more plants survive with wax protection compared to insecticide treated. Both of these requirements are within technical reach for the wax method in Scandinavia.
Potential Impact:
The results from the Weevil STOP project will support the use of more wax for protecting seedlings from the pine weevils.
There are already nurseries utilizing wax as there is a request from forest professionals to plant without the use of insecticides, and wax is one alternative for this. An important result is that the enhanced knowledge gained from the Weevil STOP project will be helpful to ensure the correct use of the wax in the nurseries. We have learned that controlled waxing and controlled cooling are integral parts of the technology. As with all new technologies being introduced, to people who are unfamiliar with wax, it is important that a system for training and learning the technology is put in place. It will be important to train the local advisory service in countries where the wax method is planned to be used. The scientific results will be of good help in this.
Because the wax method requires only low-cost equipment it is an attractive method for small nurseries. However medium large to large scale nurseries can now also take the method in use because the machine developed has proved to apply the wax correctly on the seedlings with the required speed. The impact of this is that a Norwegian nursery is planning to have one machine built for installation in May 2016.
One of the most important meeting places for new technologies is at the forest trade fares.
Here many professionals are present and there can be direct communication between users and the Weevil STOP project. The most important of the forest trade fares is Elmia Wood in Sweden.
Participation at this event for the first time in 2013 was very successful for the dissemination of the project since the wax method was highlighted in the press releases from this occasion.
The developed wax machine could only be presented to the public for the first time in June 2015 at Skogs Elmia due the IPR situation and ongoing patent application.
Another important place for dissemination has been at professional meetings. In 2014 at the yearly Norwegian ”Skog og Tre” Conference, there was an opportunity to present the available scientific results after the first period of the project. In addition, the researchers from the University of Oslo has initiated several forest trials with wax in Norway where it has been possible to gather many forest people to observe the performance of wax protected seedlings in practical plantations in south of Norway.
Similar arrangements where forest professionals can see the waxed seedlings in practical plantations have been arranged with success in Latvia and Estonia by the Latvian Forest Owner’s Association and the Estonia Forest Union respectively.
The exact registration of forest trials done by the researchers from the Swedish University of Agricultural Sciences will be used at upcoming occasions within the forest industry.
The CEPF (Confederation Europeenne des Proprietaires Forrestiers) has presented the project on several occasions, and at the “members day” in December 2014 in Brussels the project had the opportunity to have a table where information was distributed.
A broader coverage of the ongoing project was assured by an article in Norway’s largest newspaper Aftenposten in 2012 and an article in the magazine International Innovation in 2015. Both of these publications are also read by people outside of the forest industry, but with an interest for new technologies.
There have been several articles describing the project in professional magazines at national levels in Sweden, Estonia, Latvia and Norway. The consortium members have also been active in presenting the activities and goals in relevant meetings at a national level.
In October 2015 the University of Oslo had a poster presentation at the international conference for Biopesticides in Swansea, Wales.
The homepage www.weevilstop.com presents an opportunity to disseminate the project results. This home page will be updated with relevant information the first year after the end of the project.
Exploitation of foreground: Tree planting and re-forestation are very important tasks in order to secure access to wood as a raw material for the forest-based industries. Wood is the highest cost for many of these industries and the growing demand for renewable energy continues to increase competition for wood. It is therefore very important to promote and secure domestic supply of the wood raw material.
The results of the Weevil STOP project are of interest for forest businesses all over Europe because it contributes to a new practice for reforestation of conifer species without the use of insecticides. The project has developed a machine that can apply the molten wax onto the lower parts of conifer seedlings in order to form a protective layer against feeding pine weevils.
Biological studies performed on spruce seedlings coated with wax at various stages of the winter storage cycles has revealed knowledge that can be used to establish good practical routines for wax protection in a forest nursery. Laboratory studies with pine weevils and forest trials have taught us how to achieve the best protective function of wax.
In addition, field trials in the project showed that the final test of the machine in a nursery produced seedling that were relatively well protected from feeding pine weevils.
The machine developed will be of particular interest for the small to medium sized nurseries producing containerized seedlings due to the technical simplicity and moderate cost level compared to other protective coating systems for forest seedlings.
The project results will also support the use of wax as weevil protection on bare rooted conifer seedlings. This type of seedling production is more common in Europe outside Scandinavia.
The Weevil STOP project has enhanced the level of innovation and exploitation of technology in order to improve the best-practice of pest management in the forest sector during plantation for re-forestation.
The Weevil STOP project will help the forest sector to implement the new EU directive on Sustainable use of Pesticides (2009/128/EC), which restricts the use of insecticides due to health and environmental issues, and demands integrated pest management with priority given to non-chemical methods of plant protection.
The Weevil STOP project will help the forest sector to implement the EU Council Directive (EC No 1698/2005) and (EC No 74/2009) on support of rural development that demands proper water management and the protection of water quality. Currently used insecticides have strong negative impact on life in aquatic systems, insects (focus on bees) and birds, as well as human health.
The Weevil STOP project will help the forest sector to implement international and European standards on certified wood products such as FCS or PEFC and will help to meet the demand for certified wood products.
The Weevil STOP project will help the forestry sector to implement EU’s Forestry Strategy and Forestry Action Plan which demands the introduction of integrated pest management and sustainable forest management.
Professional forest organizations and the general public may have different views regarding what is the positive outcome of our research and innovation work. People and organizations making a living from harvesting forest, will usually first look at the economic benefits of the new alternative methods in a short term perspective. The public that use the forest for recreational purposes are more concerned that the techniques used in forestry are acceptable for other reasons than only the economical and want sustainable and environmentally friendly methods for the future.
The use of barrier coatings like wax or water born polymers represents an alternative to the European tradition of continuously designing new chemicals for regulating the behaviour of nature.
The results show that the use of insecticides may be replaced in many cases with a wax coated seedling. Our results from the Weevil STOP project can be used to change forest practice in the direction of reduced use of chemical insecticides because it offers a solution to the pine weevil problem in many cases where there used to be no environmentally friendly alternatives.
This wax coating is shown to be biodegradable, non-toxic and un-harmful to the environment and organisms living there. Unlike many water based coatings the wax does not contain any fungicide.
In the modern world it is now possible to re-think the strategies and find that the use of an inert wax
formula in combination with appropriate forest practice will lead to successful re-forestation and reduce the need for dangerous insecticides.
Forest is a conservative business that only slowly adopts new technologies. Although wax has been in use at a few nurseries in Sweden for some time already, the possibilities and the limits of this technology must be better understood. One aspect is that the forest seedlings are grown in different production systems, and this will result in plants of various size and shapes.
Because forestry without use of insecticides imply many practical and technological challenges for the nursery there is a need for information about how to make these changes in real life. Change of technology creates uncertainty for the nursery and reluctance for this reason may slow down the process of leaving the tradition of insecticides. The Weevil STOP project has created a solid scientific documentation that can be used to communicate how the growth of the seedling will be influenced by the wax and to establish correct procedures in the nurseries. To achieve a rapid commercialization of the method, equipment for the nurseries is critical in order to be able to treat the large number of seedlings necessary and to avoid incorrect performance of the wax method.
Besides this very practical need to produce non-chemically treated seedlings in the nurseries, it will also be necessary to provide information about the benefits of this method to a larger audience of forest owners to achieve market willingness and motivation to buy the wax coated seedlings.
The scientific understanding established in the project will give valuable support to establish wax coating as an alternative to insecticides for containerized seedlings. The reach of the enhanced knowledge is also beneficial for the use of wax protection on bare-rooted, non-containerized grown conifer seedlings.
A successful machine construction for automatic waxing of seedlings grown in containers is a commercial product needed in the nurseries because there has been no such machine available in the market until today. The results from the pilot machine in this project will establish new principles for automatically waxing seedlings and the base for constructing a fully automatic production line.
The market is offered several alternatives to insecticides today and there is uncertainty regarding what the future will look like.
Due to this it is not possible today to give an exact number of nurseries that will select this machine construction. However, it is positive that the largest nursey in Norway is installing a new machine built on the developed concept in spring 2016.
It is assumed that the wax method can get a market share of 25% of the total European market for protected seedlings without separating between containerized and non-containerized conifers.
Traditionally 40% of the 1010 million seedlings planted in EU-27 have been protected with insecticides. In the future market without insecticides several substitutes will be available such as coatings of acrylics, acrylics and sand, other coatings, collars and wax. If we assume that wax will take a 25% market share this means that 100 million seedlings will be wax treated each year in the EU.
Scientific articles: A large number of scientific measurements have been performed in the Weevil STOP project and the processing of the data gives new information of interest for the scientific community as well as for the practical use of wax on living plants. Most of the scientific results were available only toward the end of the project period. For this reason all the scientific papers will only be published after the project has been closed in October 2015.
The following scientific articles are in progress or planned based on the research work done at the University of Oslo and the Swedish University of Agricultural Sciences and their associates for the project Weevil STOP.
"Protection of conifer seedlings by wax coating: Effects on pine weevil feeding damage, seedling survival and growth"
Authors: A.V. Vollsnes, P. Öhrn, A.B. Eriksen, G. Nordlander
"Absorption and fluorescence spectra from conifer needles using array spectrophotometers"
Authors: A. V. Vollsnes, T. B. Melø
"Effects of heat on Norway spruce seedlings"
Authors: A. V. Vollsnes, T. B. Melø, A. B. Eriksen
"X-ray micro computerized tomography uncovers Norway spruce seedlings root development"
Authors: A. V. Vollsnes, B. Atkinson, C. Sturrock
"Norway spruce seedling establishment after manipulations of needles on lower stem"
Authors: A. V. Vollsnes, B. Atkinson, C. Sturrock, A. B. Eriksen
"An insecticide-free protection against pine weevil feeding on seedlings of a coastal conifer forest"
Forfattere: A. B. Eriksen, A. V. Vollsnes
List of Websites:
Project web site: www.weevilstop.com
Further information can be obtained from contacting
Jarl Markus Pettersen, Norsk Wax AS, Tel: +47 90530004, e-mail: jmp@norsk-wax.no