Über die Wirkung von Bacillus thuringiensis in Kombination mit dem synthetischen Pyrethroid Ambusch auf Operophthera brumata,Tortrix viridana und die Insektenfauna eines Eichenbestandes

In order to increase the effect of the biopreparation Thuricide HP, we mixed it with pyrethroid Ambusch, a substance highly effective against insects possessing satisfactory parameters as regards toxic residua. Using aerial application, we tested Thuricide HP as a 0.5% suspension in a dose of 1 kg in 200 l water per one ha, the same dose of the preparation combined with a sublethal dose of Ambusch (8 ml/ha, i. e., 2 g of effective substance), and Ambusch in a dose of 120 ml/ha, i. e., 30 g of effective substance/1 ha. The mortality of larvae ofO. brumata andT. viridana attained 61% after the application of Thuricide HP, 83% after Thuricide HP combined with Ambusch, 96% after treatment with Ambusch. As indicated by our results, the biopreparation killed only larvae of Lepidoptera, while pyrethroid effected the entire spectrum of insect species colonizing the crowns of the treated stand. A combination of the biopreparation with a sublethal dose of pyrethroid was sufficiently effective against the pest, with a decreased effect on the remaining insect species.