The grape mealybug, pseudococcus maritimus, is widespread in Mid-Missouri vineyards

Authors: Corcoran, Jacob

Submitted to: American Journal of Enology and Viticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/20/2026
Publication Date: N/A
Citation: N/A

Interpretive Summary: Missouri is one of the oldest grape growing regions in the Unites States, at one time producing more wine than any other state in the nation. Nowadays the Missouri wine industry produces only a small percentage of the national total, however it is still a major industry within the state, accounting for nearly 30,000 jobs and having an annual economic impact of over $3 billion. Missouri grape growers constantly battle insects and microorganisms that negatively impact grape production, which leads to lower revenues and profit margins. Grape Leafroll associated Viruses are present in Missouri vineyards and cause grape leafroll disease, one of the most serious and economically damaging diseases of grapes, worldwide. These viruses are transmitted between grapevines by soft-scale insects, such as mealybugs, however to date there have been no formal studies designed to evaluate which mealybugs, if any, may be contributing to the spread of the viruses in Missouri vineyards. This study used a combination of sex pheromone baited traps and genetic testing to determine which mealybug species were present in Missouri vineyards, when they were active and therefore more vulnerable to control tactics, and whether they were ingesting the viruses from infected grapevines. These data serve as a starting point to develop efficient and effective grape mealybug pest control programs in the region, ultimately aiming to prevent the spread of grape leafroll disease and thereby support Missouri grape growers.

Technical Abstract: The grape mealybug, Pseudococcus maritimus, is found in most grape growing regions across the USA, however, its spatial and temporal distribution in Missouri vineyards is unknown. Because the insect transmits Grape Leafroll associated Viruses (GLRaVs), which are common in Missouri vineyards, the objectives of this study were to, 1) evaluate the presence of the insect at commercial and private mid-Missouri vineyards over the course of three growing seasons, 2) confirm species identity through DNA barcoding, and 3) genetically test female mealybugs for the presence of Grape Leafroll associated Virus-3 (GLRaV3). Using sex pheromone traps, we detected varying levels of male grape mealybugs at all survey sites during two distinct periods during each growing season. Genetic testing verified that female mealybugs present on vines were Pseudococcos maritimus, and that 10 out of 54 female mealybugs collected from test vineyards possessed GLRaV3. These data confirm the grape mealybug is widespread in mid-Missouri vineyards, that it produces two distinct reproductive cycles each season, and that it ingests GLRaV3 from grapevines. As the insect has been shown previously to be capable of transmitting GLRaVs to grapevines, it is likely contributing to the high incidence rates of grape leafroll disease in the region.