Female mealybugs, if present, are in vineyards year–round, however they are only active from early spring through late summer; during the winter months they are “hibernating” underneath the bark down near the trunk of grapevines. During the growing season, female mealybugs crawl (they don’t fly) around grapevines and feed on plant material using a sharp, straw-like mouthpart to suck up precious sugar from the vines. In the process, these female mealybugs can pick up GLD–causing viruses and spread them to other vines during subsequent feedings. Male mealybugs are capable of flying, do not feed, and only live for about 3 days (they emerge to mate, then die). Because grape mealybugs have two generations each season, there are two distinct periods during which male mealybugs can be found flying around vineyards looking for females to mate with. These periods represent opportune times to detect the presence of the mealybugs and to interfere with the mealybug life cycle.

In April 2021 a monitoring program was conducted in mid–Missouri that utilized sex pheromone–baited traps to monitor grape mealybugs in vineyards. These traps emit a unique chemical that attracts male grape mealybugs from very far distances. Traps were deployed in 14 vineyards across mid–Missouri, from Kansas City to the Mississippi River, and checked every two weeks through August. The results from this survey revealed two important findings: first, that grape mealybugs were present in all 14 survey sites (Figure 1) to varying degrees; and second, that the reproductive male flights peaked during the end of May and mid–August, in 2021 (Figure 2).