How to Identify Vine Mealybug from Grape Mealybug in Vines

How Can Growers Identify Vine Mealybug vs. Grape Mealybug in Vineyards?

Several damaging mealybugs species exist within the grape production regions of the West Coast. Identifying which species is present in your vineyard is the first step in developing an effective Integrated Pest Management program.

Growers should familiarize themselves with the differences between vine mealybug (VMB) and grape mealybug (GMB). Although these pests have their own distinct biology and life cycle, they are both capable of causing significant economic damage to vineyards.

Utilizing Physical Traits of Mealybug Species for Identification

Mealybugs are dimorphic, meaning that males and females of the species have notable physical differences. Males are winged, with beaded antennae and brown bodies the length of a few centimeters. Females are wingless, with filaments, and larger oval shaped bodies. Across the two species, adults also possess unique attributes.

To begin the identification process, growers should scout their vines for potential mealybug infestations. Its important to note that mealybugs tend to congregate on different parts of the plant depending on the species and time of year. Using a hand lens throughout this process is recommended, as adult mealybugs are quite small.

Female mealybugs have several distinct visual characteristics that can help growers identify different species. One key distinguishing feature is the length and arrangement of their filaments; thin hair-like structures used for defense, sensory perception, and camouflage.

Grape mealybug photo courtesy of Haydn Lenz, Suterra.

Ostiolar fluid, a defensive mechanism used by mealybugs, is also a useful tool for distinguishing adult females of different species. When disturbed, grape mealybugs may emit small drops of this reddish, orange fluid. Ostiolar fluid can be particularly helpful in distinguishing grape mealybug from obscure mealybug, which are visually similar.

Male mealybugs also have distinguishable characteristics that assist in species identification. The most notable differences between vine mealybug and grape mealybug males are observed in their body size, and genital structure.

Photos by University of California, Cooperative Extension

General Methods for Distinguishing Mealybug Presence in the Vineyard

There are a few other methods growers may use to pinpoint mealybug infestations in the vineyard. For example honeydew, a sticky excrement produced by mealybugs feeding on grapevines, indicates mealybug activity. Both vine and grape mealybug produce honeydew, however, VMB produces more overall, drawing ants to the vineyard and promoting the growth of sooty mold. Honeydew severity is also directly related to population density of mealybugs within the vineyard.

Male vine and grape mealybugs can also be monitored through the use of pheromone-based traps and lures. These species specific lures contain female sex pheromones to effectively attract mature males. When used alongside visual scouting, trapping provides an additional tool for distinguishing between the two species. VMB is particularly concerning due to its reproductive cycle – It is capable of producing eight plus generations per year while GMB only has two generations annually.

Suterra offers monitoring solutions for both vine and grape mealybug. For more help with differentiating mealybug species, monitoring, or pheromone-based mating disruption contact a member of Suterra’s Technical Team.