Laboratory and Field Evaluation of Exotic Parasitoids ofBemisia tabaci(Gennadius) (Biotype “B”) (Homoptera: Aleyrodidae) in the Lower Rio Grande Valley of Texas

We evaluated a total of 38 exotic and 2 native parasitoid populations of the sweetpotato whitefly,Bemisia tabaci(Gennadius) (Biotype “B”) (Homoptera: Aleyrodidae) (=silverleaf whitefly,Bemisia argentifoliiBellows and Perring), using laboratory and field experiments. Numbers ofB. tabaciparasitized were counted in sleeve cages on cantaloupe melons (Cucumis meloL. cv “Perlita”), cotton (Gossypium hirsutumL. cv “Delta Pine 51”), and broccoli (Brassica oleraceaL. cv “Patriot”). Highest attack rates were found forEncarsianr.pergandiella(Hymenoptera: Aphelinidae) (Brazil) andEretmocerus mundusMercet (Spain) on melons;Eretmocerussp. (Pakistan) on cotton; andEretmocerus mundus(Spain) on broccoli. In the laboratory, these three exotic parasitoids attacked significantly greater numbers of hosts than the native species ofEncarsia pergandiellaHoward andEretmocerus tejanusRose and Zolnerowich. Selected exotic parasitoids were evaluated in the field using sleeve cages on melons, cotton, and kale (Brassica oleraceaL. cv “Siberian kale”).Eretmocerusspp. from Spain and India performed well in all crop types.Encarsianr.pergandiella(Brazil) performed well on melons, but not on kale or cotton. Selected exotic parasitoids were released at various sites throughout Hidalgo County in the Lower Rio Grande Valley of Texas. Of 29 populations released in the field, eleven were later recovered. TwoEretmocerusspecies (Spain and Pakistan) were commonly recovered throughout the evaluation period. This information will be used to prioritize the parasitoid cultures for mass rearing and release in biocontrol-based IPM programs againstB. tabaci.