Insecticidal activity of natural products against vineyard mealybugs (Hemiptera: Pseudococcidae)

Mealybugs are worldwide pests in vineyards due to direct damage and spread of grapevine leafroll disease. The objective of this study was to find natural products valuable as alternatives to synthetic insecticides for their control. Laboratory experiments and field trials were conducted in New Zealand in 2015-16 on Pseudococcus calceolariae (Maskell) and Pseudococcus longispinus (Targioni Tozzetti), and in Italy in 2016-17 on Planococcus ficus (Signoret) to assess the insecticidal activity of kaolin and citrus essential oil. Although kaolin increased Ps. calceolariae mortality in the laboratory, it was ineffective at controlling the three mealybug species in the vineyards. In contrast, citrus essential oil increased mortality of Ps. calceolariae and Pl. ficus in the laboratory and reduced leaf infestations of the latter in the vineyards. Citrus essential oil could be a good alternative to synthetic insecticides against vineyard mealybugs.