|Liu, T. - TX AGRIC EXP STN-WESLACO|
Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 9, 2001
Publication Date: April 1, 2002
Citation: Greenberg, S.M., Jones, W.A., Liu, T.X. 2002. Interactions among two species of Eretmocerus (Hymenoptera: Aphelinidae), two species of whiteflies (Homoptera: Aleyrodidae), and tomato. Environmental Entomology. 31(2):397-402. Interpretive Summary: The greenhouse and the silverleaf whiteflies are two of the most important pests of vegetable, field and ornamental crops around the world. Insecticides can provide control but are expensive and misuse often results in resistance development. Integrated pest management programs, including the use of natural enemies, should be the main strategy of crop protection. .The control of greenhouse whitefly with the parasitoid Encarsia formosa ha been an outstanding success. In 1986, the sweetpotato whitefly began appearing in commercial greenhouses. However, Encarsia formosa is less effective on this pest. The advent of silverleaf whitefly, like any new pest in a well-established system, threatens the biological control of greenhouse whitefly by Encarsia formosa due to the use of chemical insecticides which adversely affect beneficial insects, such as this parasitoid. Thus, a new system needs to be developed using parasitoids that can successfully attack both whitefly species. A tiny parasitic wasp Eretmocerus eremicus, was shown to have high potential for helping to reduce crop losses by killing whiteflies. This finding will make mass releases of the parasitoid for management of whitefly species more practical. Such biological control methods will reduce the need for additional insecticides use and also reduce associated environmental problems.
Technical Abstract: Laboratory experiments were conducted to determine the influence of two tomato (Lycopersicum esculentum Miller) varieties ('Trust' and 'Floridade') on the biology of two whitefly species, Bemisia argentifolii Bellows & Perring and Trialeurodes vaporariorum (Westwood), and the interactions of host plant and whiteflies on the biology and parasitism rate of two parasitoids, Eretmocerus eremicus Rose & Zolnerowich (a native species) an Eretmocerus mundus Mercet (an exotic species). Natural mortality, developmental time, oviposition and fecundity of Bemisia argentifolii were not significantly different from those of Trialeurodes vaporariorum. The two species of Eretmocerus responded differently to the whiteflies. Eretmocerus mundus developed faster, produced more progeny, and had greater parasitism and rate of emergence in Bemisia argentifolii than in Trialeurodes vaporariorum. Eretmocerus eremicus performed similarly on either host whitefly species, except that its females layed more eggs in Bemisia argentifolii than in Trialeurodes vaporariorum nymphs. The females of both parasitoid species that emerged from Trialeurodes vaporariorum were significantly larger than those emerged from Bemisia argentifolii. The two varieties of tomato did not have significant effects on all biological parameters for both whiteflies and parasitoids. The information resulting from these studies can be useful for development rearing strategies for whitefly parasitoids and for biological control of the two whitefly species using Eretmocerus.