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Sudan Journal of Agricultural Research

Parasitism efficiency of Eretmocerus mundus (Mercet) on Bemisia tabaci (Genn.) infesting cotton crop and its interaction with insecticides applied in New Halfa Agricultural Scheme (Sudan)

Tag Elsir Elamin Abdalla1


Abstract:

This study was conducted at the commercial fields of New Halfa Agricultural Scheme (NHAS), during 2001/02 and 2002/03 seasons, to determine the parasitism efficiency of Eretmocerus mundus (Mercet) (Hymenoptera: Aphelinidae) on Bemisia tabaci (Genn.) (Homoptera: Aleyrodidae), and its interaction with the insecticidal treatments carried against the insect pests of cotton. Parasitism started to appear in both seasons from early November and increased towards the end of the season, showing density dependence with the numbers of the whitefly nymphs. In the first season, the highest level of parasitism was 31.6%; the average for November was 16.1%, for December was 28% and for the whole season was 19.1%. In the second season, the highest level of parasitism reached was 33.5%, the average for November was 6.5%, for December was 28.9% and for the whole season was 18.9%. E. mundus delayed the insecticidal applications against the whiteflies during November in both seasons and kept them low during December so that no insecticidal interference was needed. Of the eight mixtures of the insecticide ingredients used in the two seasons, fenpropathrin + carbusulfan, endosulfan + chlorfenvinphos and diafenthiuron + profenfos caused slight decrease of parasitism. Pyriproxyfen / fenpropathrin + benfuracarb, pyriproxyfen / fenpropathrin + oxydemeton, endosulfan + amitraz, endosulfan / isoxathion and bifenthrin + oxydemeton mixtures did not cause reduction of parasitism.
 

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Sudan Journal of Agricultural Research Vol. 8 (2007) PP. 149-155