Abstract

A 1% solution of neem (Azadirachta indica A. Juss.) seed extract used against Liriomyza trifolii (Burgess) failed to increase the toxicity of untreated chrysanthemum foliage (Dendranthema morifolium (Ramat) Tzvel.) positioned above or below sprayed foliage. Untreated bean (Phaseolus limensis MacF.) leaves opposite to leaves painted with 0.4% extract were not as toxic to L. trifolii as painted leaves. Foliage on chrysanthemum cuttings that were root-dipped in 0.4% extract was toxic to leafminers but subsequent new foliage was not. Bean seeds soaked in 4% extract for 6 h germinated to seedlings which were not significantly more toxic to L. trifolii than untreated seedlings. In contrast, drenching the germination medium with 0.8% extract resulted in seedlings from which no leafminers were reared. Results indicate that complete coverage is required for maximum efficacy of neem seed extract foliage sprays against L. trifolii. Treatment of cuttings and seeds with extract has limitations. Instead, drenches to growing media are recommended as more efficacious.

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