Controlling Spider Mites in Cotton 2017

Spider mite numbers have been increasing across much of the state over the last several weeks in cotton. There have been a number of fields treated and several fields that have more than one application this year. As conditions remain hot and dry we fully expect this trend to continue. There are several materials labeled for spider mite control in cotton, however, we use one active ingredient (abamectin) on 95% of the acres because of price. Several years ago resistance to abamectin was confirmed by LSU in LA and MS. The next year the resistant populations seemed to revert back to susceptible and we have been successful with this product since that time. LSU again confirmed resistance this year in a least one population. There have been several reports in the last 7-10 days of poor control in MS as well. Although this product is extremely cheap, if you are experiencing control problems you need to switch to another active ingredient. With most miticides you will see a reduction in 3-4 days in numbers but to fully evaluate control it needs to be 6-7 days after treatment. Below are the results of a test we recently conducted in Sidon, MS and rated at 4 and 7 days after treatment. The test was treated with 10 GPA, 65 PSI, and hollow cone nozzles.