Small-holder cassava farmers in Okwusonwu-atanga in Ikpo-Obibi have since more than 40 years ago been suffering from crop attack by the white curl grub (Phyllophaga spp., Coleoptera: Scarabaeidae) pests. Several attempts have been made in the past by the farmers to find solution to the pest-invasion, but none was discovered yet. This study aimed at using the biological pest control method in the form of traditional application of the Allium spp and comparing the result with the dichlorodiphenyltrichloroethane (DDT) method. The study involved seven (7) treatments which included Allium cepa, Allium sativa, dichlorodiphenyltrichloroethane (DDT)-modern chemical pesticide, combination of Allium spp, A. cepa + DDT, A. sativa + DDT, and control which were arranged in a randomized complete block design with four replications. It was hypothesized that (i) the bio-traditional methods of soil conservation and pest control significantly decreased the impacts of Phyllophaga spp, and subsequently increased soil fertility and cassava yields as compared with the DDT and control treatments; (ii) combination of the Allium spp (A.cepa and A.sativa)showed better result in soil improvement and cassava yield than when the treatments were singly applied. Data were collected covering soil properties, cassava tuber and aboveground biomass yields, and the number of Phyllophaga spp larva per heap from the year 2010 to 2016. The result revealed that the combination of A. cepa and A. sativa treatment had the highest dry matter nutrient content in comparison with other treatments. DDT treatment showed very low yields in cassava tuber and aboveground biomass, and had relatively low Corg content than other treatments applied. Combined treatment with the Allium spp (CA) remarkably controlled the pests while, control treatment (Co) had the pests in abundance. This revealed that the application of A. cepa and A. sativa was not only economically and environmentally beneficial but was also highly productive. The study recommended that the local farmers be encouraged and emancipated on the regular use of Allium spp biological method of curl grub control instead of abandoning their lands or using DDT. Besides, further studies are needed to consolidate the findings of this result.
