Vine mealybug infestations continue to increase in northern San Joaquin Valley vineyards, and their presence has led to greater reliance on insecticides and disruption of successful IPM programs. Several strategies can be employed, with non-chemical methods important but insecticides being most effective; several newer insecticides are safer and less harmful to beneficials than organophosphates. Although more vineyards are becoming infested, populations within infested areas are declining because the judicious use of insecticides has successfully lowered mealybug populations in areas that are infested.

Cultural Control

Cultural controls are the primary means of preventing mealybug spread. The female mealybug is unable to fly so it must be carried by humans, equipment, or birds. When planting new vineyards be sure to use certified plants. Do not allow contaminated equipment, vines, grapes, or winery waste near uninfested vineyards. Movement of equipment that pushes brush or any over-the-row equipment can be a major source of infestations in new locations, so steam sanitize equipment before moving to uninfested portions of the vineyard. Do not spread infested cluster stems or pomace in the vineyard unless they have been covered with clear plastic for several weeks. Also, clusters that hang on the bark are much more susceptible to attack by vine mealybug, so any practice that increases that amount of fruit that is free-hanging will assist in mealybug control.

Biological Control

The use of the parasite Anagyrus pseudococci has provided up to 90 percent parasitism in the San Joaquin Valley. Parasitism rates can be improved by releasing them early in the season. Promoting parasites is very important because they are active late in the growing season and can reduce vine mealybug populations before the pest begins to move to the lower part of the trunk after harvest. Ants must be controlled to keep them from interfering with these natural enemies. Also, biological control is greatly hindered by disruptive pesticides. Products such as Movento, Applaud and the soil applied neonicotinoids offer good mealybug control without disrupting parasitoid populations.