Residual Effect of profenofos on Cotton Bollworm Earias insulana (Boisd.) using two Ground motor sprayer

A field experiment was carried out on spiny bollwormEariasinsulana (Boisd.) larval infestation in cotton field in Qaha district, Qalyoubia Governorate. Profenofos was sprayed by using Knapsack motor sprayer Cifarilli (20 L./Fed.) and Economy Micron ULVA (15 L./Fed.). The spectrum of droplets range between 142 -165 microns (VMD) with sufficient number ranging from 25- 268 N/cm2. The general reduction rates of larval infestation after the treatment with profenofos was 91.15% in case of using Micron ULVA equipment and 91.13% in case of using Knapsack motor Cifarilli sprayer, respectively. Profenofos residues were extracted from cotton bolls and seeds samples then determined by Gas chromatography (GC) with flame photometry (FPD). The average recoveries ranged between 91.4 % and 96%, and limit of determination was 0.005 mg/ kg. Limit of determination (LOD) were determined on samples at spiking levels 0.01–0.05 mg/ kg from the pesticide standard. Results indicated that the dissipation the pre harvest interval (PHI) of profenofos residues in cotton seeds was safe in the harvest. Economy Micron ULVA sprayer (15L/Fed.) revealed best reduction in larval infestation and best spray quality with less amount of profenofos residue.