Soil applications of two neonicotinoid insecticides to control mealybugs (Pseudococcidae) in vineyards

摘要

Grapevine leafroll-associated Virus 3 debilitates grapevines, reducing yields and juice quality, and eventually makes vineyards uneconomic. Mealybugs (Pseudococcus spp.) are the key insect pests of grapes in New Zealand because they are the principalvectors of this virus. Until recently, all insecticides registered for their control depended on direct contact, but mealybugs live in hard-to-treat parts of vines. This research tested the efficacy of two neonicotinoid insecticides, imidacloprid and SCAL 5085, that have translaminar and systemic activity. Two field trials were conducted on commercial vineyards with the insecticides applied as soil drenches. In the first trial, imidacloprid applied at 0.525 g ai/vine reduced mealybug abundance by >99% compared with untreated vines, and autumn and spring applications were equally effective. Half this rate was less effective, although drenching in autumn was better than in spring. In the second trial, treatments were applied in winter, and SCAL 5085 at 0.263 g ai/vine provided equivalent control to imidacloprid at 0.525 g ai/vine.