Control of Spider Mites on Cotton, 1981

Acaracides were applied to Acala SJ-2 cotton planted Apr 18 near Shatter, CA in 40 inch rows. Individual plots were 8 rows wide and 70 ft long. Treatments were replicated 4 times in a randomized complete block design and applied Jun 29. On Jul 21 both formulations of PIictran and Mitac at both rates were reapplied. Applications were made by high clearance sprayer equipped with drop booms using 5 solid cone nozzles per row delivering 47 gal/acre at 40 psi. Mainstem leaves (fifth unfolded leaf below mainstem terminal) were sampled on 5 post-treatment dates and processed through a sodium hypochlorite wash system. Counts were made of all active stages of the Tetranychid complex; only adult female counts are reported as they represent a consistent proportion of the total population. Mite counts were transformed by x + 0.5 for statistical analysis. Yield was determined by mechanically harvesting the 4 center rows of each plot on Oct 22.