Evaluation of Carbofuran, Chlorpyriphos and Endosulfan for the Control of Yam Beetles, Heteroligus spp. (Coleoptera: Dynastidae), in Delta State, Nigeria.


ABSTRACT. The efficacy of carbofuran (Furadan 5G), chlorpyriphos (Tricel 48EC) and endosulfan (Endocel 35EC) for the control of yam beetles (Heteroligus spp.) was evaluated in 2004 and 2005 at the Teaching and Research Farm, Faculty of Agriculture, Delta State
University, Asaba Campus and at Ugbolu, a village in Oshimili North Local Government Area, Delta State, Nigeria. The experiments were laid out in randomized complete block design and the three insecticides as well as an untreated control were replicated three times. The insecticides were applied at the time of planting at the rate of 1.75kg a.i.l 2tonnes of yam setts for Furadan 5G; 1.92L a.i.l 2tonnes of yam setts for Tricel 48EC and 0.7L a.i.l 2tonnes of yam setts for Endocel 35EC. Data collected were the number of dead beetles per heap, the number, depth and diameter of feeding holes on yam (Dioscorea rotundata cv Adaka), tuber yield and percentage yield increase over control. There were significantly higher numbers of dead beetles in chlophyriphos-and endosulfan-treated plots than in
carbofuran and untreated-control plots. All insecticide-treated plots had significantly lower
number of feeding holes, depth of feeding holes than control at the two locations. Chlorpyriphos and endosulfan were more effective than carbofuran in reducing yam beetle damage. There were no significant differences (P>0.05) in yield of tubers in insecticide treated plots compared with control plots in 2004 and 2005 at Asaba and in 2005 at Ugbolu. However, significantly lower tuber yields were obtained in untreated control plots at Ugbolu in 2004. Application of insecticides brought tuber yield increases which ranged between 23% and 68% across the locations and in the two years of evaluation.

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