Evaluation of Preventive Treatments in Low-Density Gypsy Moth Populations Using Pheromone Traps

Abstract

Pheromone traps can be used for evaluating the success of treatments that are applied to either eradicate or delay the growth of isolated low-density populations of the gypsy moth, Lymantria dispar (L.). We developed an index of treatment success, T, that measures the reduction in moth counts in the block treated adjusted by the change in moth counts in the reference area around it. This index was used to analyze the effectiveness of treatments that were conducted as part of the USDA Forest Service Slow-the-Spread of the gypsy moth project from 1993 to 2001. Out of 556 treatments that were applied during this period, 266 (188,064 ha) were selected for the analysis based on several criteria. They included 173 blocks treated with Bacillus thuringiensis (Berliner) variety kurstaki and 93 blocks treated with racemic disparlure. Analysis using general linear models indicated that disparlure treatments were significantly more effective than B. thuringiensis treatments in reducing moth captures. The frequency of repeated treatments in the same area was higher after B. thuringiensis than after disparlure applications. Treatments were more successful if the pretreatment moth counts outside of the block treated were low compared with moth counts inside the block.

Mating Disruption for the 21st Century: Matching Technology With Mechanism

“…Since 2000, 82 percent of the nearly 2.9 million acres treated in STS used mating disruption (USDA 2006). Mating disruption is a preferred tactic in STS because it is target specific, inexpensive (USDA 2004a), and effective (Sharov et al 2002c). To date the program has exceeded its spread rate reduction goals, resulting in a benefit to cost ratio of 3:1.…”

Gypsy moth mating disruption in open landscapes

“…This has been demonstrated both experimentally ( Leonhardt et al , 1996 ) and operationally ( Sharov et al , 2002a ). In the Slow the Spread of the Gypsy Moth Program (STS), a U.S. federally-funded effort involving ten states along the leading edge of the gypsy moth infestation ( Sharov et al , 2002b ), population densities generally considered most appropriate for mating disruption treatments are those in which season-long captures of male moths in pheromone-baited traps do not exceed 30 ( Thorpe et al , 2006 ).…”

Still invasive after all these years: Keeping gypsy moth out of British Columbia

“…Opponents of spray programs have advocated application of gypsy moth pheromones for species-specific disruption of mating. A formulation utilizing pheromone-impregnated silicone flakes has been registered in the USA and used extensively in gypsy moth management with favourable results (Tcheslavskaia et al 2005), especially at the low densities characteristic of eradication programs (Sharov et al 2002). No such registration exists in Canada and so experiments have necessarily been carried out by deploying a high-density network (9 per acre) of retrievable, pheromone-baited traps in hopes of catching males before they can mate.…”