Rapid Shoot Growth

Look for thrips if cold weather persists.

Look for spider mites and their natural enemies weekly on first-emerging leaves. Map areas of concern for bloom monitoring.

Monitor leafhoppers weekly starting a month after budbreak or whenever first nymphs appear. Keep records (example monitoring form PDF).

Continue checking pheromone traps for:

• Omnivorous leafroller
• Orange tortrix in coastal areas

Keep records (example monitoring form PDF).

In southern San Joaquin Valley, deploy vine mealybug pheromone traps around April 1 and check every two weeks.

• If males are caught or honeydew, sooty mold, or ants are found, look for nymph/female infestations on surrounding vines.
• Keep records (example monitoring form PDF).
• Treat if needed according to the Pest Management Guidelines.

Monitor caterpillars if they have been a problem in the past:

• Western grapeleaf skeletonizer
• Grape leaffolder
• Orange tortrix (in coastal vineyards)
• Omnivorous leafroller

Map areas of concern for bloom monitoring.

If European fruit lecanium scale has been a problem in the past, monitor female development on old wood.

Manage grey and Argentine ants if mealybugs and scale are a problem.

Monitor for sharpshooters:

• Glassy-winged sharpshooter

In coastal regions near riparian and landscape areas check for:

• Blue-green sharpshooter

Change traps weekly. Keep records (example monitoring form PDF).

Monitor for flagging. If you see a flag, distinguish between Botrytis shoot blight and branch and twig borer.

Monitor leaf wetness. Track powdery mildew ascospore release and mildew risk index. Treat if needed according to the Pest Management Guidelines.

Survey weeds to plan a weed management strategy.

• Control weeds that escaped a dormant season treatment, using postemergence herbicides or cultivation. Record which weeds escaped for future herbicide treatment decisions.

Other pests or pest damage you may see.

• Eutypa dieback
• Phomopsis cane and leaf spot