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R. E. Webb, R. L. Ridgway, K. W. Thorpe, K. M. Tatman, A. M. Wieber, L. Venables, Development of a Specialized Gypsy Moth (Lepidoptera: Lymantriidae) Management Program for Suburban Parks, Journal of Economic Entomology, Volume 84, Issue 4, 1 August 1991, Pages 1320–1328, https://doi.org/10.1093/jee/84.4.1320
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Abstract
A specialized gypsy moth, Lymantria dispar (L.), management program was designed for use in urban-suburban parks and other wooded public lands. A guide based on number and size of egg masses, host susceptibility, and previous defoliation was developed to assist in making treatment decisions. One or two applications of Bacillus thuringiensis Berliner (subspecies kurstaki) (40 billion international units per ha) or one application of diflubenzuron (Dimilin) were applied at 28 g (AI)/ha with the goal of preventing ≥30% defoliation in any part of a management unit. Land managers selected the control material used. The trial program was implemented in six management units including one county park in 1988, and four parks and the Beltsville Agricultural Research Center (BARC) in 1989. B. thuringiensis was applied once to 993 ha of park land and 812 ha at BARC; diflubenzuron was applied once to 176 ha at BARe. B. thuringiensis was applied twice to 220 ha of park land and 233 ha at BARe. Average corrected larval mortality based upon counts made before and after treatment were 69.0% and 85.7%, respectively, for one or two applications of B. thuringiensis and 93% for one application of diflubenzuron. Although no defoliation ≥30% occurred on lands receiving two applications of B. thuringiensis or one application of diflubenzuron, such defoliation occurred on 1.0% of the untreated land and 4.2% of the area treated with one application of B. thuringiensis, probably because of sampling error and inadequate spray coverage.