The three most important mealybugs in the North Coast are vine mealybug (VMB), grape mealybug (GMB), and obscure mealybug (OMB). Gill's and long-tailed mealybug are present in other regions, but not prevalent in the north coast. Mealybugs can be found anywhere on the vine (trunks, cordons, leaves, etc.). They are phloem-feeders and excrete honeydew. Excessive honeydew can lead to the growth of sooty mold that can soil leaves and clusters. All vineyard mealybugs transmit grapevine leafroll-associated viruses (GLRaV). Male mealybugs do NOT transmit GLRaV because they do not feed in the adult stage; as nymphs they are vectors.
