Vol. 2 No. 1
Effect of Some Herbicides on Egg Parasitism and Development of Trichogramma chilonis Ishii (Trichogrammatidae : Hymenoptera).
Abstract: Herbicides may affect natural enemy activity either by destroying their food and host resources or by killing them directly or by repelling them from the treated area. Laboratory study was conducted to work out the effect of six herbicides namely, pretilachlor, paraquat, sulfosulfuron, 2, 4 - DEE, Sumisoya and imazosulfuron, each at three dosages, on the pupal mortality, egg parasitism and subsequent development of Trichogramma chi/on is Ishii, an egg parasitoid of lepidopteran crop pests. The herbicides caused 0 - 10.65% mortality of the treated pupae and all the herbicides were considered to be safe to pupal stage of the parasitoid. 2, 4 - DEE caused considerable reduction to the parasitism of treated eggs by the parasitoid, whereas, others had little to moderate levels of adverse effect on egg parasitism. The herbicides had no marked adverse effect on adult longevity. None of the herbicides affected tl1e subsequent emergence of the adults from treated host eggs. Reduction of egg parasitism in some herbicides may be either due to the repellent action of these chemicals themselves or due to adjuvanls used in fommlation.
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