Effect of Pesticide Residues on Perilla Leaf by Nozzle Types of Knapsack Sprayers

Abstract

This study was carried out to clarify the effects of the application of pesticide by different spray nozzle types on pesticide residues. The average droplet size and discharge rate were investigated when the manual compressed sprayer with two head disk type nozzle and the knapsack engine powered sprayer with two head fan shape nozzles were used. The fan type nozzles were classified into three types by the number of orifice in the nozzle. Three type nozzles tested were fan with one orifice, fan with two orifices and fan with three orifices. Fan (trade name : D-3) with 2.4 L/min. of the discharge rate and 76 µm of the average droplet size while maintaining constant pressure 1.1 ± 0.2 MPa, and fan D-35 with 2.6 L/min. and 90 µm while maintaining constant pressure 1.0±0.2 MPa were appropriate. The orifice size of D-3 was 0.65 mm length × 0.45 mm width and the orifice size of D-35 was 0.62 mm length × 0.46 mm width. The residue levels of imidacloprid on perilla leaves among four applications by four different nozzles show significantly difference with 5% significance level. The residue levels 3.76~3.92 mg kg −1 by fan or disk type is smaller than 4.52~4.92 mg kg −1 by fan II or fan III. The residue levels of imidacloprid on perilla leaf were different depend on the spray nozzles type.