Community Research and Development Information Service - CORDIS

Knowledge about the susceptibility of the pine processionary moth larvae to bacillus thuringiensis kurstaki applications

The susceptibilities of Thaumetopoea pityocampa/wilkinsoni larvae to Bacillus thuringiensis formulations were screened in 2003 and 2004. Eggs and larvae were collected from pine forests in Israel, Italy and France. Larval mortality bioassays were conducted with formulations of Delfin, Dipel DF and Foray 48B at concentrations ranging from 0.001 to 0.1%.

Significant differences in susceptibility to Bt were recorded among populations that were either regularly treated, often treated, or never treated with Bt. The mortality recorded in a population that was never treated with Bt was twice that in a regularly Bt-treated population. The mortality bioassay was optimised with regard to the patterns of larval hatching and age. The correlation between susceptibility to Bt and the possible resistance to the microbe is discussed.

The reported decreasing susceptibility of Thaumetopoea to Bt in the intensive Bt IPM that was revealed in the present study must be taken into account in adopting guidelines for the use of Bt to control this pest. Factors to be considered include records of persistence of Bt in the forest during the insect season. The outcome of the result has been already applied to the Integrated Pest Management in the above countries, mainly by avoiding to repeat applications on the same areas. The monitoring plan of another results of this TIP (Pheromone 32691) has been applied to identify the areas.

We expect that other countries where IPM is currently carried out will adopt the same procedure. The information will be spread by the publication of scientific and technical papers and on the project web site. For this reason, we think that the public Forest Health Services of all the countries where the pest is present can be interested, as well as a few SME involved in the production and trading of the bio control preparations. Research and extension institutes can be interested as well. In the calculation of the potential follow-up, we included only the qualified technical staff involved in decision-making but not the end-users of the forest resources (citizens).

The expected benefits consist of a reduction of the whole area annually treated against the moth in the core areas. However, we are observing that the range expansion associated with the global change is requiring the pest control in new areas (e.g. the Alps), thus increasing the money invested by private and public forest owners. This will require an increase of the qualified jobs related to the survey work and the organization of the IPM in each country.

Reported by

Derech Hamqabim PO Box 6
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