Investigation on the Efficiency of Electrostatic Charge and Spinning-disc Sprayers in Comparison with Common Sprayers Using Two Concentrations of hexythiazox (EC 10%) against Two-spotted Spider Mite, Tetranychus urticae Koch., on Common Bean

Two-spotted spider mite (Tetranychus urticae Koch.) is an important pest on common bean in Iran which causes quantitative and qualitative damages to legumes. Its activity on the backside of host leaves reduces the efficiency of sprayer machines. In this research, efficiency of six sprayer machines using two concentrations of hexythiazox (Nissorun®, 0.5 and 0.3 L/ha) were studied. The experimental design was a factorial test conducted based on the completely randomized block design with 14 treatments in 3 replications. The sprayers included wheelbarrow sprayer 100 liters), atomizer sprayer with simple head, atomizer sprayer with electrostatic head, atomizer sprayer with micronair head, micronair sprayer with tail boom and knapsack sprayer. Sampling of T. urticae population was performed one day before and 1, 3, 5, 7, 14, 21 and 28 days after spraying. The results show that the highest and the lowest efficiency percentages are 83.74 and 23.46% for electrostatic sprayer and micronair sprayer with tail boom, respectively. Also, the efficiency percentages for other sprayers measured are 76.50%, 57.41%, 43.22%, and 36.81 for wheelbarrow sprayer, atomizer sprayer with micronair head, atomizer sprayer with simple head and knapsack sprayer, respectively. The amount of solution used in the electrostatic sprayer, atomizer sprayer with micronair head and micronair sprayer with tail boom were 42.69, 134.4 and 56.25 l/ha, respectively, which indicates decrease in the consumption as compared with the others. Hence, the electrostatic sprayer is recommended as the most effective sprayer for the control of Two-spotted spider mite in the bean fields.