R.A. Van Steenwyk, S.K. Zolbrod, R.M. Nomoto, W.W. Coates, J.K. Hasey, R.B. Elkins, J.A. Grant
Walnut husk fly (WHF), Rhagoletis completa Cresson, is a serious insect pest of walnuts in California. Control of WHF relies on repeated applications of broad-spectrum insecticides combined with a feeding stimulant to suppress adult flies before oviposition. The broad-spectrum insecticides suppress beneficial insects and mites that in turn suppress a number of secondary insect and mite pests. Thus an efficacious and environmentally benign WHF control needs to be developed to reduce or eliminate broad-spectrum insecticides. To this end, laboratory and field studies were conducted from 2002 to 2005 to evaluate spinosad as a replacement for broad-spectrum insecticides. In laboratory trials, spinosad at low rates was not as efficacious as malathion but was as efficacious as esfenvalerate and superior to pyrethrin. WHF mortality as a result of feeding on GF-120 was adversely affected by increased WHF density. The longevity of GF-120 appears to be very short under hot and dry California conditions. In field trials, GF-120 and Success 2SC provided significantly lower infestation as compared to the blank bait check and was equivalent to the grower standard of malathion or chlorpyrifos.
Van Steenwyk, R.A., Zolbrod, S.K., Nomoto, R.M., Coates, W.W., Hasey, J.K., Elkins, R.B. and Grant, J.A. (2010). WALNUT HUSK FLY CONTROL WITH REDUCED RISK INSECTICIDES . Acta Hortic. 861, 375-382
DOI: 10.17660/ActaHortic.2010.861.51
Rhagolestis completa, walnuts, spinosad, California, pest management

Acta Horticulturae