The research aims at developing biological control methods against economically important rotting agents : Botrytis cinerea, the grey mold agent of tomato and strawberry and the complex Botrytis cinerea, Penicillium sp. and Gloeosporium sp on apple and pear.
To develop biological control methods potentially antagonistic rotting agents were isolated from naturally occurring epiphytic organisms on the surfaces of apple and strawberry fruits, on the floral organs of strawberries and on wounds in tomato plants from pruning. In total, 1300 strains of fungi, yeast and bacteria were isolated. A number of small scale screening tests were carried out under controlled conditions for each crop and pathogen combination to assess the potential antagonistic ability of each of the microorganisms isolated. The most interesting results were obtained with post harvest Botrytis and Penicillium on apples. 7 microbial strains (yeast) were selected for their protective ability. The ratio between inoculum concentration of antagonists and pathogens, time between application of the protective yeasts and innoculation of the pathogen appeared to be important factors controlling the level of projection. Studies of microbial metabolism and growth were initiated with the object of developing media for large scale fermentation of selected antagonistic strains.
Microbial strains will be evaluated for their capacity to protect the different model crops (apple, pear, strawberry and tomato) in preharvest conditions (field and orchard treatments) or in postharvest conditions (storage diseases).
Study of micro-organisms production in fermentor and their formulation will have to ensure immediate efficacy of selected micro-organisms through their rapid multiplication and the production of adequate metabolites upon the treated plant surface.
This project aims at integrating these biological control methods with the other techniques of plant protection (chemical control and cultural practices).