Assessing Dispenser-Based Control on Mealybug (Hemiptera: Pseudococcidae) and Ant (Hymenoptera: Formicidae) Populations in Virginia Vineyards

Mealybugs (Hemiptera: Pseudococcidae) are one of the prevalent pests infesting wine grapes in the eastern United States. Their close association with ants (Hymenoptera: Formicidae) provides them with protection against natural enemies. The study examines mealybug species identification, dominant ant genera present in vineyards, and the impact of sugar dispensers on ant and mealybug populations, as well as fruit cluster infestations. Field trials were conducted in two commercial vineyards in Virginia, USA, both with a history of mealybug infestations. Sampling plots with or without sugar dispensers were compared to assess differences in mealybug and ant population densities and fruit cluster infestation levels. Two mealybug species, Pseudococcus maritimus (Ehrhorn) and Ferrisia gilli Gullan were recorded from both sites. Some dominant ant genera, including Tetramorium Mayr, Lasius Fabricius, Solenopsis molesta (Say), Crematogaster Lund, and Pheidole Westwood were found in close association with mealybugs. Ant populations remained consistently low in the untreated plots throughout the sampling season. While sugar dispensers containing insecticide initially attracted a higher number of ants, the population subsequently declined. Fruit cluster infestation was also highest in the untreated plots lacking sugar dispensers.