Krizhko A. Ecological aspects of the Bacillus thuringiensis using in the potato protection system from the Colorado potato beetle.

This thesis is devoted to base ecological expediency of B. thuringiensis strains putting on practice, like the preparation for plant protection bioagents from the potato beetle, as compared with the chemical insecticide Calipso arguments on facts. The strain B. thuringiensis 994 can produce the parasporal crystals and exotoxin during sporification. The strain B. thuringiensis 787 can produce only the parasporal crystals during sporification. Previous studies showed that the effectiveness of potato plants processing against potato beetle larvae with liquid biopreparation on the basis of B. thuringiensis 994 and 787 strains are respectively 87,4 and 89,7%. Unlike the Calipso, B. thuringiensis strains don't have influence on the potato beetle predators Cocinella septempunctata L. and Forticula auricularia L. viability in the potato agrocenosis. Putting on practice the biopesticides basing on B. thuringiensis, causes the depression the soil fungal population in first 2 days. B. thuringiensis strains was shown to demonstrate the antagonism to phytopathogenic fungi Fusarium oxysporum and Alternaria solani. The metabolites of B. thuringiensis cultures was shown to stimulate the Azotobacter biomass growing. The Calipso makes the supression for it growth. The inseсticidеs is observed not to couse a significant influence on soilbiological activity by the intensity of carbon dioxide secretion and the activity of cellulose destruction. But the process of cellulose destruction weakened under the influence of Calipso. Processing the potato plants with B. thuringiensis leads to opression the ammonification bacterium, epigenous fungus, actynomyces of phylloplane microphlora. Calipso has an opression effect on actynomyces. Nevertheless, after the insecticides processing, the full restoration of phylloplane microcommunity take place for 7 days. It was established fact that the exotoxin produced B. thuringiensis 994 strain and Calipso reduced the amount of chlorophyll and carotenoids in potato leaves. Potato extractive substance showed the antibacterial properties to cultures of B. thuringiensis strains and Calipso causes decreasing of starch grains dimensions in tubers, and increasing of sugar amount. This changings is able to testify the aggravation in tuber's nutrient properties.