RELEASE OF ERETMOCERUS-LONGIPES COMPERE (HYMENOPTERA, APHELINIDAE) AGAINST ALEUROTUBERCULATUS-TAKAHASHI DAVID ET SUBRAMANIAM (HOMOPTERA, ALEYRODIDAE) ON JASMINE PLANTATIONS IN THE FUZHOU REGION OF SOUTHEASTERNCHINA

The field release of the parasitoid, Eretmocerus longipes Compere (Hym enoptera: Aphelinidae) against the whitefly, Aleurotuberculatus takaha shi David et Subramaniam (Homoptera: Aleyrodidae), was conducted in co mparison with an insecticide application and untreated sites on jasmin e plantations in the Fuzhou region of southeastern China in 1997. The results showed that after release of the parasitoid in early April the whitefly population was significantly suppressed by the parasitoid, w ith the population decreasing at rates of 24.9 % in the first peak in mid May, 48.3 % in the second peak in late September and 77.5 % at the end of sampling in late October, compared with the population at the untreated site. The release for each plot of 6 m in row and 6 m in col umn of about 1000 parasitoids on 10 leaves (rotal 36 plots with 36000 parasitoids) significantly increased the population levels off. longip es ranging from 210 ind./10 leaves in the first peak in mid June, 11.1 times as high as that with 19 ind./10 leaves in the untreated site an d 35.0 times as high as that with 6 ind./10 leaves in the insecticide application site, to 187 ind./10 leaves in the second peak in late Oct ober, 3.0 times as high as that with 62 ind./10 leaves in the untreate d site and 8.9 times as high as chat with 21 ind./10 leaves in the ins ecticide application site. The biotic and abiotic mortality factors of the whitefly were tested by means of age-specific life tables and are discussed in the paper. It is suggested that an increase in the paras itoid population level can be achieved by artificial releases of E. lo ngipes in the early season of a year to result in a successful biologi cal control of the whitefly.