Evaluation of insecticides and Agril polyester cover against whitefly (Bemisia tabaci Gennadius) in tomato crops
Azam, K.M. | Zouba, A. | Razvi, S.A. | Al-Raeesi, A.A. (Department of Plant Sciences, College of Agriculture, Sultan Qaboos University, P.O.Box 34, Al-Khod 123 (Oman))
Field experiments were conducted on tomato crops over a two year period to evaluate the efficacy of six insecticides, viz. triazophos, phosphamidon, dimethoate, buprofezin, and Aflix (endosulfan + dimethoate) each at 0.05 and Repelin (plant product insecticide) at 1 concentration along with a cultural treatment by covering the plants with Agril (a polyester material) for the control of whitefly, Bemisia tabaci. The insecticides were applied eight times at weekly interval immediately after transplantation. The whitefly eggs, nymphal population counts and the per cent incidence of tomato leaf curl virus (TLCV) were recorded every week for eight weeks in all the treatments. The incidence of whitefly was more severe in the second year (i.e. 1992-93) as compared to the previous season. Among the various treatments, the Agril cover recorded the least incidence of whitefly and of TLCV. The average counts of eggs were 0.0 and 5.47 and of nymphs 0.54 and 0.58 per 10 leaflets and TLCV were 4.32 and 4.76 in Agril cover treatment during the first and second year, respectively. Among the insecticides tested only Aflix recorded less incidence of the pest, being 3.46 and 30.4 eggs per 10 leaflets and 0.94 and 5.34 nymphs per 10 leaflets during the two years of study, respectively. The other treatments were less effective in reducing pest and disease incidence. The crop under Agril cover recorded the maximum yield of 34.57 and 26.15 t/ha of tomatoes as compared to 16.48 and 10.82 t/ha in control during the first and second year, respectively.
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