Development and evaluation of PAU multi-purpose sprayer to control whitefly (Bemisia tabaci) in cotton

A multi-purpose high clearance sprayer was developed with three types of spraying mechanism, viz. auto-rotate gun, drop-up boom and boom nozzles. The experiment was conducted during 2016 at Abohar in cotton growing region of South-western Punjab at six farm locations to evaluate sprayer performance and its bio efficacy against whitefly (Bemisia tabaci). It was observed that the auto-rotate gun sprayer produced lowest droplets VMD of 259.01 μm followed by boom type of 290.28 μm, drop-up boom type of 312.12 μm and knapsack sprayer of 328.50 μm, respectively. The maximum droplets density/cm2 was found to be 31.67 (drop-up boom sprayer), 26.29 (auto-rotate gun), 21.34 (boom sprayer) and 18.13 (knapsack sprayer). However, more leaf area coverage was observed as 31.67% in drop-up boom sprayer followed by 26.29% of auto-rotate gun type, 21.24% of boom-type and 16.86% of knapsack sprayer. The higher whitefly control was obtained with a drop-up boom sprayer of 80.69-88.65% followed by autorotate gun sprayer of 80.31-85.10%, boom-type of 72.81-86.27% as compared to knapsack sprayer of 63.37-75.45%. Lowest operation cost was found to be ₹ 150/ha for auto-rotate gun-type followed by ₹ `239/ha a for boom type and ₹ 291/ha for drop-up boom spraying system of multi-purpose high clearance sprayer, however, it was maximum ₹ 475/ha for knapsack sprayer. The similar, trend of cost saving was observed as 68.55, 49.82 and 38.80% per ha as compare to knapsack sprayer.