APHELINID PARASITOIDS AS SUSTAINABLE BIOLOGICAL-CONTROL AGENTS IN GREENHOUSES

Aphelinid parasitoids have been used for control of pests in greenhous es since the 1920s, but large scale application started only some 25 y ears ago. Today, several aphelinid parasitoids are commercially used f or the biological control of scale, aphid and whitefly pests in greenh ouses. A success story is the biological control of greenhouse whitefl y, Trialeurodes vaporariorum, with the aphelinid Encarsia formosa. Enc arsia is applied on 5000 ha of vegetable crops worldwide. Weekly, more than 20 million individuals of E. formosa are mass reared and shipped to growers in 20 countries. About 10 years ago, another whitefly spec ies, Bemisia sp., developed to pest status and a search for control of scales and aphids in greenhouses is summarized, as well as the status of commercial biological control with aphelinid parasitoids. Further, the questions whether effective natural enemies can be identified bef ore introduction and if autoparasitoids should be imported and release d are addressed. Finally, the usefulness of parasitoid biotype studies to recognize suitable candidates for biological is considered.