Crops Affected: Grapes

States Affected: CA, HI, WA, OR

Life Cycle: The grape mealybug lays yellow to orange eggs within a white, cottony egg sac. These hatch to the immature stage, referred to as crawlers. During spring, most crawlers move towards the base of spurs or under loose bark on canes and then onto expanding green shoots, reaching maturity around mid-May to early June. From mid-June to July, eggs hatch, and first-generation crawlers move to feed on fruit and foliage. Second generation adults appear in late summer and early fall, with most laying overwintering eggs on old wood. Grape mealybugs overwinter as eggs or crawlers in or near the egg sac under loose bark or in the cordons and upper trunk areas.

Damage: Mealybug damage susceptibility differs among grape varieties. Varieties with clusters near the base of the shoot are most vulnerable. Mealybugs harm grapes by contaminating clusters with cottony egg sacs, larvae, adults, and honeydew, which is often covered in black sooty mold. Mealybugs can also transmit viruses to the grapes.

Season to Trap: May to October

How To Use: Hang trap with lure inside at shoulder height near at risk or affected crops. Replace lures every 30 days through the season, and replace traps when 70% saturated. Adult males are attracted to the pheromones in the lure and the color of the traps in this kit. Once they land on the sticky trap, they become ensnared, never to mate or lay eggs again.

Additional IPM Solutions: Avoid practices that destroy or disrupt native beneficial insects. To aid in mealybug control, it's crucial to manage honeydew-seeking ants so they don't drive off the beneficial insects. Effective ant control methods include tillage, common vetch cover crops, or ant baits. Monitor beneficial parasitism by collecting mealybugs and holding them in small containers at room temperature to detect parasite emergence. Leaving untreated areas in the vineyard can provide refuges for parasites. Training vines to hang freely and not touch wood can reduce infestations. For small populations, a single treatment during delayed dormant or spring may suffice. For high infestations, treat in early spring and summer, focusing on the vulnerable crawler and young nymph stages with properly timed insecticide applications.