Effects of Bacillus thuringiensis Treatments on the Occurrence of Nuclear Polyhedrosis Virus in Gypsy Moth (Lepidoptera/ Lymantriidae) Populations

1988

S. 1706-1714

2 Abb., 3 Tab., 38 Lit. Ang.

Unselbständiges Werk

200042623

Journal of Economic Entomology 1988 ; 81(6), S. 1706-1714

The effect of aerial applications of Bacillus thuringiensis Berliner on the prevalence of endemic nuclear polyhedrosis virus (NPV) among gypsy moth larvae, Lymantria dispar (L.), was studied at three different locat ions in Massachusetts and Connecticut in 1982, 1983, and 1984. Rates of NPV-caused mortality were determined from larvae collected weekly intervals and fromlarvae hatched from field-collected egg masses and reared on artificial diet in the laboratory. NPV mortality was lower among larvae collected from plots treated with B. thuringiensis than in adjacent, untreated plots. Similarly, egg masses carried more virus to the next generation in untreated plots than did egg masses from treated plots. Reduced mortality from NPV in the B. thuringiensis-treated plots usually resulted in higher egg mass densities during subsequent years than would have occurred without treatment. The compensatory nature of the B. thuringiensis-NPV interaction may account for much of the variability observed in previous field tests of B. thuringiensis formulations.