Control of Epiphyas postvittana (lightbrown apple moth, Lepidoptera: Tortricidae) on grapevines with tebufenozide

Feeding by leafroller larvae damages grape bunches and makes them susceptible to Botrytis cinerea disease. Leafroller infestation of foliage and bunches and the incidence of botrytis was measured on vineyards in Gisborne, Hawke's Bay and Marlborough over 2 years. Forty-four blocks received no leafroller-active insecticides while 22 were sprayed once pre-flowering with the selective insect growth regulator, tebufenozide. Tebufenozide very effectively reduced infestations and gave season-long control. On leaves, untreated blocks averaged 14 leafrollers/search compared with 4 on sprayed blocks. Comparative figures for fruit at harvest were 18/100 bunches and 3/100, respectively. There was a trend for lower botrytis incidence in blocks where tebufenozide was used. Over 99% of the leafrollers reared were Epiphyas postvittana. Parasitism of larvae and pupae at 67% on leaves and 50% in bunches, was similar in untreated and treated blocks. Epiphyas postvittana in vineyards is easily managed using tebufenozide, which did not compromise biological control.