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ARS Home » Research » Publications at this Location » Publication #74815


item Thorpe, Kevin
item Webb, Ralph

Submitted to: Virginia Gypsy Moth Advisors Annual Review
Publication Type: Proceedings
Publication Acceptance Date: 9/10/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: The gypsy moth virus product, Gypchek, was registered with the U.S. Environmental Protection Agency in 1978 as a general use pesticide to control the gypsy moth, a serious pest of hardwood forests in the northeastern United States. Because it directly affects only the gypsy moth, it has the potential to play an important role in situations where gypsy moth control is needed, but where a high degree of protection of animals other than the gypsy moth is desired. The development of a carrier, or ready-to-spray liquid into which gypchek could be dissolved, is considered to be a potentially important advance in the use of this biological control tactic. The objective of this study was to conduct an aerial field test of a newly-developed commercial carrier at different numbers of applications and application volumes. The study was conducted on high gypsy moth populations in Virginia in 1995. The carrier + gypchek spray provided effective foliage protection at both the one gallon and the 0.5 gallon volumes, and with both single and double applications. The results of this study provide data to assist the effective use of the carrier + gypchek combination against the gypsy moth. This information should also help forest managers, gypsy moth control specialists, and government agencies decide if they should consider this treatment as an option for gypsy moth management.

Technical Abstract: A field test of a commercial carrier for the gypsy moth nucleopolyhedrosis virus product, Gypchek, was conducted in 1995 to test the following treatments: 1) double applications of carrier at one gallon per acre per application; 2) double applications of carrier at 0.5 gallons per acre per application; 3) a single application of carrier at one gallon per acre; 4) double applications of a lignosulfonate-molasses tank mix at two gallons per acre per application; and 5) an untreated control. All treatments except the control included gypchek at 4 x 1011 viral occlusion bodies per acre. Larval mortality ranged from 73% with a single application of carrier to 90% with the high volume, double application of carrier. Mortality was significantly lower among larvae collected from plots treated with only a single application. Estimated larval density was 126 per m2 in the untreated plots, 57 per m2 in the single application plots, and less than 25 per m2 in the plots treated with the other treatments. Defoliation in the control plots averaged 38%, which was significantly higher than the 15 to 23% defoliation which occurred in the treated plots. There was no detectable difference between the lignosulfonate-molasses tank mix and the double application of carrier at either the 1 gallon or the 0.5 gallon volume.