Cotton fields were treated with the entomopathogenic nematode, Steinernema riobravis, and Vydate^® L for the control of plant parasitic nematodes. Short staple cotton grown near Coolidge, Arizona, was treated at a rate of 1 billion and 2 billion S. riobravis nematodes per acre, and 0.5 lb a.i. Vydate^® L per acre. Untreated cotton received an application of water only. Treatments were applied through a subterranean drip system with 12 inch spaced outlets. Applications were made in the daily irrigation cycle of 0.33 inches of water, normal irrigation cycles followed.

Products were uniformly distributed over the treated fields. Entomopathogenic nematodes persisted throughout the 6 week experimental period at the 1 billion per acre rate. However, nematodes applied at 2 billion per acre rate disappeared rapidly. Populations of various plant parasitic nematode species were monitored subsequent to treatment application. Nematodes were extracted using a standard sugar flotation technique and counted in 1 ml slide samples. Both Meloidogyne incognita and Tylenchorhynchus spp. populations were reduced by S. riobravis applied at 1 billion per acre rate. Phytoparasitic nematodes were reduced following application of Vydate^® L, but control was not sustained beyond one week.