ENCARSIA FORMOSA GAHAN AS A REGULATOR OF NURSERY WHITEFLY NUMBERS IN PROTECTED GROUND
The data are summarized and analyzed on the use of a specialized parasite, nursery whitefly Encarsia formosa Gah., as a regulator of dangerous phytopage numbers by the example of Russia’s Premorey Krai. The bioagent colonization efficiency is marked to depend upon temperature regimen, air humidity and presence of different pests on the same plant. Under optimal conditions (+24…26 ºС), Encarsia females are capable for parasitizing on 140…160 whitefly larvae. The temperature decreasing +18…22 ºС, its prolificacy becomes 3 times less. Encarsia’s colonization in whitefly larvae foci was done by hanging cardboard cards of 6 х 4cm size with Encarsia’s pupae sticked on them evenly and the cards were placed at a 2–3 m distance from the whitefly focus. Encarsia» imagoes flown out of the pupae spread uniformly over the whitefly larvae colonies. The efficiency of the technique made up 88–92 %. On the sweet paprika, the parasite exercised a full control over whitefly numbers with the parasite-host ratio of 1 : 8, 1 : 10 throughout the period of vegetable crop production in the protected ground. As for cucumber and tomato plants, the whiteflies’ density was steadily restricted with the parasite colonizing at low level for a long time. Following the optimal conditions of Encarsia colonization in the foci of nursery whitefly in the protected ground allows to cancel chemical treatments against the pest and ensures ecologically safe vegetable output.