Tips To Control Argentine Ants In Vineyards

Controlling vineyard ants is the most important habitat management tool to reduce mealybug abundance and damage. Ant species vary in dominance in different vineyards regions; both the Argentine ant, Linepithema humile, and the native grey ant, Formica aerata, are commonly found in the Central Coast region, These ants tend vineyard mealybugs for their honeydew—some species more aggressively than others. This mutualism has clear benefits for the ants, which are provided with a carbohydrate food source, and in return, ant-tending has been credited with protecting mealybugs from natural enemies.

A liquid bait program, developed as an alternative to barrier sprays for ant management, has been shown to suppress Argentine ant populations, resulting in a reduction in grape and obscure mealybug damage. Three commercial bait products, Vitis™ (imidacloprid), Gourmet Liquid Ant bait™ (borate) and Tango™ (methoprene) are available for use in vineyards and orchards. Bait stations are typically deployed at a rate of 15 per acre, but higher rates may be justified to manage larger Argentine ant populations. Baits are deployed in early spring (April-May) to coincide with an increased demand by ants for food during this period of warming and intensive colony growth.

For a full review of the liquid bait program, in the Sustainable Viticulture edition of the California Agriculture journal,click here.