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A formulation of Bacillus thuringiensis Berliner was effective against larvae of Porthetria dispar (L.) when applied at rates of 16x109 and 8x109 international units (I U) per acre. Defoliation caused by the gypsy moth in unsprayed areas approached 100%, indicating an ad- equate larval population for evaluation. Three applications of the lower dosage produced both foliage protection and larval mortality. Partial defoliation was noted in the treated areas and may have resulted from incomplete coverage or the presence of other forest defoliators not susceptible to the spray. Bioassays demonstrated the residues of the spray to be toxic to early-stage larvae for one month following the last application. In a laboratory bioassay using 2nd instars, the median lethal concentration was 96.2 IU/ml diet. Since postspray egg masses were not reduced, the possibility of a feeding inhibition phenomena is suggested.
Document Type: Research Article
Publication date: February 1, 1973
More about this publication?
Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.