Submitted to: Sweetpotato Whitefly Progress Review Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/1/2002
Publication Date: 6/1/2002
Citation: Interpretive Summary:
Technical Abstract: A stand of cotton, var. DPL 5415, was established at UC Desert Research & Extension Center 21 March 2001. Seven insecticide treatments and an untreated control were replicated four times in a randomized complete design. The following insecticide treatments were applied as foliar sprays: Assail 70 WP at 0.075 and 0.1 lb ai/acre, Danitol 2.4EC at 0.2 lb ai/acre plus Orthene 97 at 0.5 lb ai/acre, Danitol 2.4EC at 0.2 lb ai/acre plus Thiodan 3 EC at 0.5 lb ai/acre, Knack 0.86 EC at 0.054 lb ai/acre, and Novaluron 0.83 EC at 0.013 lb ai/acre and at 0.026 lb ai/acre. Foliar insecticide spray treatments were applied 11 July, 7, 21, 30 Aug 2001. Silverleaf whitefly (SLW) adults were sampled from ten plants at random in each plot via the leaf turn method using the fifth main stem leaf from the terminal. SLW nymphs were counted on 1.65 cm^2 leaf disks from fifth position, main-stem terminal leaves extracted from ten randomly selected plants in each plot. SLW adults and nymphs were sampled on 10, 16, 20, 23, 26, 31 July, 6, 13, 20, 27 Aug, 4, 10, 17 Sept 2001. Seed cotton was hand picked from 0.002 acre per plot and seed cotton yield data were recorded. Seed cotton samples were ginned at the USDA-ARS Western Cotton Res. Lab. in Phoenix, AZ and lint samples were sent to the USDA/ARS Cotton Quality Res. Station in Clemson, SC for stickiness and sugar analysis. Seasonal means for SLW adults for all of the insecticide treatments were significantly lower than the untreated control except the Knack 0.86 EC treatment, P LT or = 0.05. The Assail 70 WP treatments and the Danitol 2.4 EC + Orthene 97S treatment had seasonal means for whitefly adults that were significantly lower than the means for the Novaluron insecticide treatments. Seasonal means for SLW nymphs for all of the insecticide treatments were significantly lower than the untreated control treatment. The Assail 70 WP treatments had seasonal means for SLW nymphs that were significantly lower than the means for all other insecticide treatments. The seasonal mean for SLW nymphs was significantly lower for the Knack 0.86 EC treatment compared to the means for all other insecticide treatments except the Assail 70 WP treatments. The Danitol 2.4EC plus Orthene 97 treatment had a seasonal mean for SLW nymphs that was significantly lower than the means for Danitol 2.4EC plus Thiodan 3 EC and the Novaluron 0.83 treatments. There were no differences among the treatments for pounds of seed cotton per acre.