Toxicity and Efficacy of Glufosinate on Twospotted Spider Mite in Cotton

Foliar applications of glufosinate (Liberty) herbicide were evaluated for there efficacy towards twospotted spider mites in Liberty Link cotton. Liberty at 43 fl-oz/ac provided mite control equivalent to a standard miticide applicaiton of Portal at 16 fl-oz/ac. However, under droughty conditions, significant phytotoxicity was observed. Additionally, the cost per acre for applying Liberty at 43 fl-oz was significantly greater than the applicaiton of Portal. Leaf dip bioassays suggest that Liberty is toxic to spider mites with an LC50 of 6 ppm. Because of the high cost associated with Liberty, it is not considered a viable treatment targeting spider mites, but may prove useful for controlling mites when used for weed management.