Анотация: In certificated forest ecosystems in Serbia, Bacilus thuringiensis ssp. kurstaki insecticides are well-accepted and most widely used pesticides for control of one of the most important economically harmful defoliators of Lepidoptera order - gypsy moth (Lymantria dispar Linne, 1758), in progradation phase, when number of pests is relatively small. When number is greater, it is assumed that so-called ` soft ` ecotoxicologically favourable preparations Avaunt, Alverde, Coragen, registered for application in agriculture, but not in forestry, can be used for inhibition of multiplication. The experiments of biological efficacy of those pesticides were established in the period 2009-2010, during the third larval instar of the gypsy moth. From the beginning of feeding till the end of the two groups of experiments the caterpillars were fed with natural (Pedunculate oak leaves) and synthetic food, but from the third instar the food was shortly soaked in water solutions of the analysed doses of the preparation. Results of laboratory studies of biological efficiency of above preparations showed that they have preconditions for application in forest ecosystems. The high biologic efficiency (90.52 percentage and 100 percentage for Avaunt, 99.53 percentage and 100 percentage for Coragen, 97.16 percentage and 100 percentage for Alverde), mechanism of rapid inhibition of larvae feeding, and thereby inhibition of leaf mass damage, resistance to water rinsing, high selectivity, and small quantities of application, anticipated a bright future for them

Забележки: Conference ` Forestry: Bridge to the future `, may 13-15, 2010, Sofia