IN VITRO COMPATIBILITY BETWEEN CHEMICAL AND BIOLOGICAL PRODUCTS USED FOR SEED TREATMENT

The study reveals the possibility to use simultaneously biological and chemical control products as efficient and environmental friendly seed treatment for pest and disease control, which could provide a decrease of the chemical dose needed for plant protection. This phytosanitary strategy promotes microbial strain from Beauveria, Bacillus and Pseudomonas genera that can be used together with some chemical products for plant protection in order to decrease the amount of chemical product per unit area. Therefore, two chemical insecto-fungicides were selected based on the ecotoxicological risk assessment and legislation related to plant protection products (Regulation (EC) No 1107/2009 and Directive 2009/128/EC). The compatibility studies between the bio-control microorganisms and chemical pesticides were based on the microbial strains interaction with the active substance from the chemical insecticide and insecto-fungicides (imidacloprid 600g/l and mix of imidacloprid 460 g/l with thiram 176 g/l, respectively). The viability of the microbial strains was studied under laboratory conditions. The entomopathogenic fungi Beauveria bassiana (Bals.) Vuill. exhibit good compatibility with imidacloprid insecticide (600 g/L a.s. in comercial product), which does not affects the biological parameters of the beneficial microorganism. However, B. bassiana exhibits high sensitivity towards insecto-fungicide mixture, which inhibits completely the spore germination at the recommended concentrations. The results on the bacterial compatibility with the chemical phytosanitary products (at different concentration) did not inhibit completely the bacterial growth. The insecticide based on imidacloprid 600 g/l, did not affect the growth of any Bacillus biocontrol strains, when it was tested at 20% concentrations. Only the insectofungicides mixture, in 20% concentration, caused moderate growth inhibition (less than 5 mm) to some of the bacterial strains tested.