Abstract
The effect of spray coverage on bollworm mortality was measured on mature cotton variety CM-495-PB planted at
Post-graduate Agricultural Research Station (PARS) experimental fields, University of Agriculture, Faisalabad
Spray coverage was found directly related to mortality of cotton bollworms Conventional over-the-row sprayers
achieve very little deposit on leaves near the ground and on the underside surfaces of leaves throughout the
canopy (2-5 %) Water Sensitive Papers were installed on three levels of plants (top, middle, and bottom) on both
sides of the leaves to examine the spray coverage. The greatest spray coverage values on upper and lower leaf
surfaces were 49.67 % and 65.87 % respectively at V2P202 treatment, while for conventional system it was 35.6
% on upper sides of leaves and 0.4 % on lower sides of the cotton leaves. The relationship between spray
coverage and bollworm mortality was established for drop-pipe university boom sprayer Hundred percent
mortality of American and spotted bollworm occured after one week for a surface coverage of 52 % and 61 75 %
respectively. A software programme was developed to analyze spray coverage on the computer in Java
language.
Keywords: Surface coverage, bollworm, boom sprayer, mortality
