Evaluation of Neem Seed and Citrus Peel Powder for the Management of Maize Weevil, Sitophilus zeamais Motsch. (Coleoptera: Curculionidae) In Sorghum

Abstract

The study yWas cohducted at the Plant Protection Laboratory of Haramaya
University in a controlled environment of 28±2°C temperature and 75±5% relative
humidity. The objective was to determine the effective doses of Azadirachta aulica
and Citrus sinensis peel powder for the management o f Sitophilus zeamais. The
treatments were arranged in completely randomized design (CRD) with four
replications. Fifty unsexed 3-6 days old maize weevil adults were introduced to
each glass jar containing 1 kg Sorghum bicolor (L.), variety muyra-2 seeds. Neem
seed and citrus peel powder were compared with Ethiolathion 5% dust and
untreated control at the rate o f 7.5. 1 5 ,2 5 , 50 and 100 g k g '1 o f seeds. Parent adult
maize weevil mortality, F, progeny emergence and percent protection, grain weight
loss, damage and germination at all rates of citrus peel powder (CPP) and neem
seed powder (NSP) showed significant differences over the untreated control
(P < 0 .0 l), except for grain damage (%) at 7.5 g CPP (P >0 .0 l). At the rate o f 25, 50
and 100 g both test botanicals resulted in 100% adult weevil mortality, 95-100%
grain protection, reduced weevil emergence, reduced grain damage, reduced grain
weight losses and produced statistically comparable efficacy with Ethiolathion 5%
dust (P<0.01). NSP at 7.5 and 15 g and all rates o f CPP did not reduce grain
germination rate, whereas at higher rate o f 25- 100 g NSP statistically decreased
germination o f the treated grains (P<0.01). Further research is warranted to assess
efficacy o f these botanicals under farmer’s storage condition.