Interaction between ants and mealybugs in Virginia vineyards

Ants have been observed in proximity with the honeydew-producing insects including mealybugs. The interactions between ants and honeydew-producing hemipterans have been studied extensively in multiple ecosystems and this association has been found to be beneficial to both of the insects. Most mealybugs have the potential to form root colonies on grapes, though the tendency varies among species. Their movement to roots, and spreading in that area, is facilitated by ants (Daane et al. 2007). An understanding of the role of ants may provide a clearer view of the epidemiology of grapevine leafroll disease transmitted by mealybugs. Grasswitz and James (2008) studied the movement of grape mealybug between vines, including self-directed movement by walking, or movement aided by the wind. Movement by either means was limited. However, an ant-assisted movement was not included. In a study of mealybugs and grape leafroll virus, Jones and Nita (2016) found that movement of the disease was not affected by wind – this would be consistent with the ant-assisted movement of the vector mealybugs. The objective of our study is to investigate the potential role of ants in the movement of mealybugs in the vineyard.