Pantnagar Journal of Research

Abstract

An auto-rotate gun sprayer was evaluated for its bio-efficacy to control whitefly Bemisia tabaci (Genn.) in the cotton crop. Two experiments were conducted at six farmers’ fields of south-western (cotton-growing region) Punjab. The number of adult whiteflies was counted before and 3, 7 and 10 days after spray. Water sensitive papers were attached at three different points of reach (top, middle, bottom) upper side and underside of the leaf on the plants to find performance parameters, viz. droplet diameter, droplet density, per cent area covered and volume of spray deposition. Droplet density, area covered and volume of spray deposition were found significantly higher in case of the auto-rotate gun sprayer as compared to a knapsack sprayer. However, the volume median diameter (VMD) of droplets was found significantly higher in the case of a knapsack sprayer of 347.85 µm as compared to an autorotate gun sprayer of 286.95 µm. The whitefly control in the cotton crop as compared to untreated treatment after 10th days of autorotate gun and knapsack sprayers spray by using pyriproxyfen100 g a.i./ha having bio-efficacy of 64.39 % and 65.65 % and by using flonicamid 75 g a.i./ha was found 85.72% and 74.70%, respectively. The cost of operation of the auto-rotate gun sprayer was found to be USD 4.11/ha as compared to knapsack sprayer with USD 6.85/ha. The cost, labour and time-saving in the spraying of the autorotate gun sprayer as compared to knapsack sprayer was found to be 39.98, 93.44 and 96.64%, respectively.