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Title: INNOVATIVE METHODS FOR THE RELEASE, ESTABLISHMENT AND MONITORING OF BEMISIA PARASITOIDS AND PREDATORS

Author
item Hoelmer, Kim
item GOOLSBY, JOHN

Submitted to: Proceedings of First International Symposium on Biological Control of Arthropods
Publication Type: Review Article
Publication Acceptance Date: 5/1/2002
Publication Date: 5/1/2003
Citation: HOELMER, K.A., GOOLSBY, J.G. INNOVATIVE METHODS FOR THE RELEASE, ESTABLISHMENT AND MONITORING OF BEMISIA PARASITOIDS AND PREDATORS. PROCEEDINGS OF FIRST INTERNATIONAL SYMPOSIUM ON BIOLOGICAL CONTROL OF ARTHROPODS. 2003.

Interpretive Summary: Biological control played a major role in an interagency research and action plan developed for sweetpotato (silverleaf) whitefly in the U.S. in the 1980s. Natural enemies obtained by foreign explorers were evaluated against whitefly on key crops in laboratory and in large-scale field evaluations and releases. A variety of colonization techniques involving agricultural demonstration projects, urban and farmsite host plants, commercial nurseries, and managed refugia were employed by project scientists. Demonstration projects showed that parasitism of whitefly could be increased with early season releases of parasitic wasps that were compatible with the use of selective pesticides such as imidacloprid. High rates of parasitism were also obtained by including small numbers of "banker" seedling plants containing whitefly already parasitized by wasps among clean melon transplant seedlings. Managed "refuges" of mixed plants grown alongside crops allowed natural enemies to move from the refuges into the crops, resulting in higher levels of biological control of whitefly. By 2001, surveys showed that introduced natural enemies of whitefly had be come established in the Imperial Valley, CA, and the Lower Rio Grande Valley, TX.

Technical Abstract: Biological control had a key role in a research and action plan developed to counter infestations of Bemisia tabaci in the United States during the 1980s. Parasitoids obtained by foreign exploration were screened against B. tabaci on selected crops. Top performing species were mass-reared at insectaries to provide material for larger-scale field evaluations and releases. To increase the likelihood of successful introductions, releases were made using a variety of colonization techniques involving agricultural demonstration projects, urban and farmsite host plants, commercial nurseries, and managed refugia. Field augmentation with exotic Eretmocerus species showed that parasitism could be increased with early season releases that were compatible with the use of selective pesticides. High rates of parasitism were also obtained by introducing "banker" seedling plants containing B. tabaci parasitized by Eretmocerus. Studies with actively managed refuges consisting of mixtures of crops or native plant hosts that were situtated adjacent to crops demonstrated that parasitoids from refuges successfully dispersed into neighboring crops and increased in numbers even after releases were ended. By 2001, surveys showed that introduced Eretmocerus spp. had been recovered from B. tabaci at widely separated desert sites west of the Imperial Valley. No evidence of nontarget impacts to any of the non-target species monitored has been detected.