Field Tests of Acaricides Against Pacific Spider Mite on Grapevines

Field tests for the control of Tetranychus pacificus McGregor showed that plots with the highest pretreatment counts of 3 replicates of each acaricidal treatment tended to have the highest post-treatment counts with a probability of less than 0.001 by the t test. Use of ranked data appeared to be useful in the statistical analysis of treatments applied to grapevines of widely varying degrees of initial infestation. Among the more effective acaricides tested were Tranid® (exo-5-chloro-6-oxo-endo-2-norbonanecarbonitrile O-(methylcarbamoyl) oxime), Azodrin® (3-hydroxy-N-methyl-cis-crotonamide dimethyl phosphate), formetanate, phosalone, and Dessin® (2-sec-butyl-4,6-dinitrophenyl isopropyl carbonate).