Control of Spider Mites and L. Hesperus on Cotton, 1986

Pesticides were applied to 'Acala SJ-2' cotton near Shafter and Five Points, Calif., planted 15 Apr and 17 Apr, respectively. Individual plots were 16 and 24 rows wide, respectively (1.02 m/row), and 46 m long. Treatments were replicated 4 times in a randomized complete block design and were applied by high-clearance ground sprayer equipped with drop booms using 3 or 5 hollow-cone nozzles/row, depending on plant size, delivering 140 or 234 liters/ha at 2.8 kg/cm2. Mainstem leaves (25/plot, 8th unfolded leaf below mainstem terminal) were sampled on 5 or 6 posttreatment dates and processed through a sodium hypochlorite wash system. Counts were made of all active stages of the Tetranychid complex. L. hesperus were sampled by 50 net sweeps/plot (19.4 m2) on 8 sample dates/location. All arthropod counts were transformed (x + 0.5) for analysis of variance; raw means are reported here.