Department of Entomology, Punjab Agricultural University, Ludhiana
Experiments were conducted under field conditions at two naturally available wind speeds (0–5 km/hr and 12–24 km/hr) on swath width in ULV spraying with motorized knapsack sprayer fitted with a restrictor for the control of jassid on cotton, with malathion LVC. Effect of orientations of the lance of the sprayer both in respect of height of lance and its angle was also studied. At the lower wind speeds, swath width of 8.4m was found to be effective upto 7 days after the treatment as against 1.2m at the higher wind speeds. All. the orientations of the lance tried gave equal effective swath widths at the lower wind speeds but at the higher speeds the lower lance orientation (82 cm height from ground and 75° angle with respect to vertical axis of the body) gave slightly better kill of the pest.
