Journal of Economic Entomology (1997) 90, 404-411

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Tong-Xian Liu and Philip A. Stansly (1997)
Effects of pyriproxyfen on three species of Encarsia (Hymenoptera: Aphelinidae), endoparasitoids of Bemisia argentifolii (Homoptera: Aleyrodidae)
Journal of Economic Entomology 90 (2), 404-411
Abstract: Effects of the phenoxy juvenile hormone analog pyriproxyfen, were evaluated in the laboratory on larvae, pupae, and adults of the endoparasitoids Encarsia pergandiella Howard, E. transvena (Timberlake), and E. formosa Gahan, as well as on their host Bemisia argentifolii Bellows and Perring. Although B. argentifolii nymphs reared on sweet potato leaves and treated as 1st, 2nd, or 3rd instars with pyriproxyfen developed to the pupal stage, <5% adult emergence was observed. However, when treated in the 4th instar, adult emergence was >70%, and when treated as pupae, >97%. Of the 3 parasitoids tested, pyriproxyfen was least harmful to E. pergandiella and most deleterious to E. formosa. Concentrations of 1.00, 0.05, and 0.01 mg (AI)/liter applied to whitefly nymphs 6.5 d after parasitization caused significant reduction in subsequent adult emergence of E. formosa at the greatest rate, but not of E. pergandiella. Effects of treatment of whitefly nymphs containing E. formosa pupae (11.4 d after parasitization) were even more striking - 73.5 and 44.6% reduction in emergence at the 2 highest rates, with wing deformations observed in a large proportion of emerging adults. Development time of all 3 Encarsia species was increased significantly by exposure to pyriproxyfen shortly after oviposition, and parasitization of B. argentifolii by E. formosa adults treated as larvae was reduced 21.4-56.8% compared with untreated parasitoids. However, residues of 2 higher rates reduced the progeny by 30.7-42.3% and rate of emergence by 11.2-27.6% with E. formosa, and to a lesser extent the progeny by 21.7-29.3% and adult emergence by 3.2-11.0% of E. transvena. Thus, pyriproxyfen proved to be effective against B. argentifolii, safe to E. pergandiella, and relatively safe to E. transvena, but relatively toxic to E. formosa, especially pupae.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Tong Xian Liu, Philip A. Stansly

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
control - general
Research topic(s) for beneficials or antagonists:
resistance to pesticides

Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.

Bemisia tabaci biotype MEAM1
Encarsia formosa (parasitoid) Bemisia tabaci biotype MEAM1
Encarsia pergandiella (parasitoid) Bemisia tabaci biotype MEAM1
Encarsia sophia (parasitoid) Bemisia tabaci biotype MEAM1