ENTOMOPATHOGENS BACILLUS THURINGIENSIS AS A BASIS OF MICROBIAL PREPARATIONS OF A WIDE SPECTRUM OF ACTION

The aspects of using microbial preparations based on Bacillus thuringiensis for the plants protection against harmful organisms was discussed. The aim of researches was to evaluate bacteria B. thuringiensis 87/₃ new strain as a potential basis for broad spectrum biological preparations. The efficacy of the Bacillus thuringiensis 87/₃ strain was demonstrated in laboratory and field conditions using Leptinotarsa decemlineata Say.(L_1-2), as well as phytopathogenic micromycetes Venturia ssp. The results of biological effectiveness Bt 87/₃ strain study on the larvae of сolorado potato beetle L_1-2 showed that in the first days after treatment, the process of reducing the number of larvae occurred slowly, but the plants were not damaged due to the antifidant effect. Expressive maximum of the Leptinotarsa decemlineata Say. (L_1-2) larvae death recorded on the tenth day with an infectious load of 1.1. The results research indicate a high biological efficacy of the Bt 87/₃ preparation action on the colorado potato beetle larvae – 98.4%. It has been established the high adaptability of B. thuringiensis 87/₃ strain (the titre of the metabolic spore-crystalline complex is from 3.6 to 4.8 billion/ml.), entomocidal (99.4%) and antifungal effect, which is shown in reduction of the diseased plants number by the apple scab causative in 1.5-2 times, in comparison with the control variant. It was established that the treatment of apple trees with a suspension based on Bt 87/₃ significantly reduced the number of scabbed leaves compared with the control, namely, in the treated variants, the percentage of lesion was less than 40%, while the control ranged from 55% (Glory Winners) to 70% (Wilmut variety). A wide range action of endoforming bacteria Bt demonstrates the prospects of their use for phytoprotection