Development of Parasitoid inoculated Seedling Transplants for Augmentative Biological Control of Silverleaf Whitefly (Homoptera: Aleyrodidae)

Abstract

Methods are presented for producing banker plants, transplants that are used for augmentation of Eretmocerus parasitoids for biological control of Bemisia argentifolii in cucurbit crops. Preference tests were conducted with B. argentifolii and its parasitoid Eretmocerus hayati for ten cantaloupe varieties to determine their suitability for use as banker plants. Bemisia argentifolii showed a significant preference for the varieties Copa de Oro and Mission, whereas, E. hayati showed the greatest preference for Copa de Oro, Mission and Primo. The impact of imidacloprid on the development of parasitoid immatures on banker plants was evaluated. Thirteen days after release of E. hayati, banker plants treated with imidacloprid produced equivalent numbers of parasitoids as did control plants. Field trials, incorporating the use of banker plants and imidacloprid, were conducted for two seasons in spring cantaloupes and one season in fall watermelons. Numbers of parasitoid progeny produced per cantaloupe banker plant were approximately 94.6 and 102.1 in two trials during the Spring of 1997 and 1998. Field release rates per acre in cantaloupe were estimated to be 68,946 and 29,970 for the 1997 and 1998 trials, with banker plants incorporated with regular transplants at a ratio of 1:10 and 1:30 respectively. In the watermelon trial, the mean number of parasitoid progeny produced per banker plant was determined to be 94.6, with an estimated 4156 released per acre with a ratio of 1:30 banker to regular transplants. Banker plants were shown to be a reliable method for field delivery of Eretmocerus parasitoids in transplanted and direct seeded cantaloupe or watermelon crops. The methods used to produce parasitoid inoculated banker plants are discussed.