INSECTICIDE EVALUATION AND EFFICACY
The tarnished plant bug (TPB) for many years was considered a minor pest of cotton. In areas of low insecticide output (e.g., boll weevil eradication and high Bt cotton planting areas), insecticide-resistant tarnished plant bugs (TPB) have become a major threat to profitable cotton production in parts of the Mid South. Use of insecticides, however, remains a grower's only choice for control of TPB for the immediate future. Control is obtained with organochlorine, organophosphates and carbamates insecticides that were usually applied for other cotton pests. The efficacy of various insecticides for TPB varied within each insecticide class. New insecticide chemistry, when available from industry, for TPB control is initially evaluated at Stoneville, MS in spray chamber bioassays. Plant cuttings are placed in floral water pics and sprayed with the recommended rates of insecticides. After plants are dry; 3 day old TPB adults are caged on cotton plants and mortality readings are taken each day for 72 hr Insecticides that have acceptable mortality in the spray chamber are carried to the field and evaluated in large replicated field plots for control.
The use of insecticides remains as a cotton producer's only choice of control of the TPB for the immediate future. At the present time different classes of insecticides such as; organophosphates, carbamates, chloronicotinyl, neonicotinoid are recommended in the Mississippi Cotton Insect Control Guide. Insecticides in the recommendations include: Acephate, Bidrin, Provado, Malathion, Monitor, Vydate, Curacron and Centric. The majority of early season sprays are applied on a band with ground equipment use chloronicotinyl and neonicotinoid insecticides. Mid to late season TPB sprays consist mainly of organophosphates. During the last 10 years the rates of organophosphates used to control plant bugs have doubled due to TPB selection and tolerance.
Within cotton fields, detection of localized areas of damaging TPB populations with spatial imaging technology can significantly reduce insecticide use of further improve cotton IPM for other pests. However, tests need to be conducted over large acreages to verify that these strategies will be effective in TPB management and/or reducing the cost of cotton production.
For more information contact:
PO Box 346
141 Experiment Station Rd
Stoneville, MS 38776
Snodgrass, G. L., W. P. Scott, J. T. Robbins, and D. D. Hardee. Early season herbicide treatment of wild host plants in marginal areas near fields, roads, and ditches and resulting numbers of tarnished plant bugs in treated and untreated areas. In Proc. Beltwide Cotton Prod. Res. Conf. www.cotton.org/beltwide
Snodgrass, G. L., and W. S. Scott. 2002. Tolerance to acephate in tarnished plant bug in the Mississippi river delta. Southwest Entomol. 27:191-199.
Snodgrass, G. L., and W. S. Scott. 2002. Effects of ULV malathion use in boll weevil eradication on resistance in tarnished plant bugs. In Proc. Beltwide Cotton Prod. Res. Conf. www.cotton.org/beltwide