Effect of spray application techniques on spray deposits and residues of bifenthrin in peas under field conditions.

Five spraying techniques were evaluated for the coverage of bifenthrin on peas under open field conditions. Ultra-low volume sprayer (ULVA) and Ground hydraulic motor with conventional spray gun (GMG) gave number mean diameters (NMDs) from 27 to 68 and from 33 to 73 N/cm2 with volume mean diameter (VMD) from 50 to 120 and from 320 to 508, respectively. Homogeneity factor values were 2, 2, 2.5, 2.8, and 13.5 in ULVA, Domestic modification of the ground hydraulic motor sprayer with one nozzle (GMO), Ground hydraulic motor sprayer with vertical boom (GMV), Motorized knapsack mist blower sprayer (MKM) and GMG. The percentages of the lost spray in the ground were 23, 39, 21, 24, and 36% for ULVA, MKM, GMG, GMO and GMV, respectively. An analytical method was developed using QuEChERS and GC-ECD to determine the initial deposit of bifenthrin in pods and leaves. Initial deposits were from 0.006 to 0.05 mg/kg in pods and from 0.03 to 0.66 mg/kg in leaves. The most efficient technique was single nozzle Twinjet, followed by the motorized knapsack sprayer.