Gypsy moth : aerial tests with Bacillus thuringiensis and pyrethroids /

Two formulations of Bacillus thuringiensis Berliner, Dipel® and Thuricide®-16B, and two synthetic pyrethroids, resmethrin (SBP-1382) and bioethanomethrin (RU 11679) were aerially tested against the gypsy moth, Porthetria dispar (L.), in Connecticut.Dipel applied at the rate of 1 lb/acre or 7.26 Billion International Units (BIU)/acre and Thuricide-16B applied at the rate of 2 qt/acre or 8 BlU/acre provided some foliage protection.Pyrethroids applied at the rate of 0.05 lb active ingredi- ent/gal/acre did not provide foliage protection.The knock down rate was high, but many larvae recovered, ascended the trees, and continued to feed.There was a significant reduction in the number of egg masses per acre in the B. thuringiensis plots as compared to the untreated plots.The number of egg masses in plots treated with pyrethroids was not different from the untreated plots.There was a marked reduction in the posttreatment egg mass counts as compared with the pretreatment counts in all plots.In the B. thuringiensis plots the number of eggs per mass was sig- nificantly higher than in the untreated plots, but there was no significant difference in the number of eggs per mass be- H. Williams for their technical assistance.We especially thank the pilot, Mr. T.