Response to Capture 2 EC, 1988

Abstract

Abstract Edelson & Magaro (1988; Response of spider mites to Capture, 1987, Insecticide & Acaricide Tests, Vol. 13, p. 265) indicated that the LC50 for Tetranychus spp. collected from cotton in south Texas during 1987 was 15.4 ppm. Two source populations of carmine spider mite were compared in the 1988 test. One population was collected from a commercial corn field near Mercedes, Tex., in July and the other was collected from a cotton field in Mercedes in August. The corn field had not been treated previously with pesticides. The cotton field had been treated 6 times with cypermethrin (Ammo, 0.5 lb [AI]/acre) prior to collection of the mites. Disposable 50- by 9-mm Petri dishes were treated with a 15.4-ppm solution of Capture 2 EC according to methods discussed by Edelson & Magaro (1988). Twenty to thirty adult female mites were placed in each of 6 replicates treated with the LC50 dose and 20-30 adult females were placed in 6 untreated control dishes. The dishes were held at 25°C for 24 h and then the mites were examined to determine mortality. The mites were considered dead if they could not move more than one body length when prodded. The same techniques were used to test populations from each field.