Grape (Table)

Year-Round IPM Program for Table Grapes

(Reviewed 10/08, updated 10/08)

These practices are recommended for a monitoring-based IPM program that reduces environmental quality problems related to pesticide use. Links take you to information on how to monitor, forms to use, and management practices. Track your progress through the year with the annual checklist form.

Water quality becomes impaired when pesticides move off-site and into water. Air quality becomes impaired when volatile organic compounds move into the atmosphere. Each time a pesticide application is considered, review the Pesticide Application Checklist at the bottom of this page for information on how to minimize environmental quality problems.

Note: This program covers the major pests of table grapes in the San Joaquin and Coachella valleys. For wine and raisin grapes, see the Wine and Raisin Grape Year-Round IPM Program. Information on additional pests and pests of wine and raisin grapes is included in the Grape Pest Management Guideline.

Delayed-dormancy

(San Joaquin Valley, February; Coachella Valley, December to January)

What should you be doing at this time?
On a warm day (above 65° F), monitor trunks, cordons, and spurs for:
  • Mealybugs
  • Ants associated with mealybugs and European fruit lecanium scale
  • Overwintering spider mites (orange)
  • Cutworms

Keep records (example monitoring form PDF). Manage if needed according to the Grape Pest Management Guidelines.

Just before budbreak, in the San Joaquin Valley, place omnivorous leafroller pheromone traps in the vineyard.
  • Check traps twice weekly until a biofix date is established; thereafter, check traps weekly.
  • Record biofix for the first moth.

Keep records (example monitoring form PDF).

Just before budbreak, place sticky traps in and around the vineyard for glassy-winged sharpshooter.

Other pests or pest damage you may see:

  • Rodents
  • Branch and twig borer
  • Click beetles
  • Bud beetles
  • Eutypa dieback
  • Bot canker

Budbreak

(San Joaquin Valley, March; Coachella Valley, January to February)

What should you be doing at this time?
On a warm day (above 65°F), monitor trunks, cordons, and spurs for:
  • Mealybugs
  • Ants associated with mealybugs and European fruit lecanium scale
  • Overwintering spider mites (orange)
  • Cutworms

Keep records (example monitoring form PDF). Manage if needed according to the Grape Pest Management Guidelines.

In San Joaquin Valley continue to check pheromone traps twice weekly for omnivorous leafroller, if biofix has not been reached.

  • Record biofix for the first moth (example monitoring form PDF).
  • Check traps weekly after biofix date is established.
Monitor for powdery mildew using the risk assessment index followed by visual inspections.
  • Treat if needed according to Grape Pest Management Guideline.
If rainfall is predicted after budbreak, consider treating for phomopsis cane and leaf spot in sensitive varieties (Thompson seedless, redglobe).
Note locations of vines showing poor budbreak for future assessment of abiotic disorders or diseases.
Check sticky traps for glassy-winged sharpshooters.
Survey weeds to plan a weed management strategy if not completed earlier in the season. If herbicides are to be used:
  • Record observations (example survey form PDF).
  • Make your selection based on weed survey observations.
Other pests you may see:

Rapid shoot growth

(San Joaquin Valley, March to May; Coachella Valley, February to May)

What should you be doing at this time?
Look for spider mites and their natural enemies on emerging leaves weekly.
  • Map areas of concern for bloom monitoring.
Monitor leafhoppers weekly, starting a month after budbreak or when first nymphs appear. When samples reach 10 leafhoppers per leaf:
  • Keep records (example monitoring form PDF).
  • Treat if needed according to Grape Pest Management Guideline.
Manage mealybugs (Pseudoccocus, vine):
  • Place vine mealybug pheromone traps in the vineyard:
    • Southern San Joaquin Valley, April 1
    • Coachella Valley, March 1
  • Check traps every 2 weeks.
  • Sanitize equipment before moving to uninfested areas in the vineyard.

If grape or vine mealybug females are found on the vine, treat according to Grape Pest Management Guidelines.

Monitor caterpillars if they have been a problem in the past:
  • Western grapeleaf skeletonizer
  • Grape leaffolder
  • Omnivorous leafroller

Map areas of concern for bloom monitoring.

Continue checking pheromone traps for omnivorous leafrollers.
If European fruit lecanium scale has been a problem in the past, monitor female development on old wood.
Manage ants if mealybugs and scale are a problem.
Check sticky traps for glassy-winged sharpshooters.
Watch for for shoot flagging (wilting) to determine if caused by:
  • Powdery mildew
  • Botrytis shoot blight
  • Branch and twig borer
Monitor visually for powdery mildew spores and by using mildew risk index.
  • Treat if needed according to Grape Pest Management Guideline.
Survey weeds to plan a weed management strategy if not completed earlier in the season. If herbicides are to be used:
  • Make your selection based on weed survey observations.
  • Record your observations (example weed survey form PDF).

Look for these disease symptoms:

If infected plants are found, consult the Grape Pest Management Guidelines.

Other pests you may see:

Bloom to véraison

(San Joaquin Valley, early May to July; Coachella Valley, April)

What should you be doing at this time?
Monitor for western flower thrips, particularly in vineyards near drying grains.
  • Manage according to Grape Pest Management Guideline.
Monitor leafhoppers, spider mites, and mealybugs weekly.
  • Keep records (example monitoring form PDF).
  • Manage if needed according to Grape Pest Management Guideline.
Examine leaves and shoots for Botrytis bunch rot and powdery mildew.
  • Manage if needed according to Grape Pest Management Guideline.
If European fruit lecanium scale has been a problem in the past, monitor for egg hatch to time treatment.
Continue to check omnivorous leafroller pheromone traps weekly.
Continue monitoring pheromone traps for vine mealybug.
  • If males are caught or honeydew, sooty mold, or ants are found, look for females on surrounding vines.
  • Keep records (example monitoring form PDF).

If grape or vine mealybug females are found on the vine, manage according to Grape Pest Management Guideline.

Remove basal leaves and lateral shoots in the fruit zone beginning around berry set to minimize summer rot, Botrytis bunch rot, and leafhopper populations, and to maximize application coverage.
  • Time leaf pull before first-generation grape leafhoppers become adults.
  • Remove only the leaves on the shaded side of the canopy on non-divided trellis systems to prevent heat damage and sunburn of sensitive varieties (Thompson seedless, redglobe).

Treat for Botrytis before rain according to Grape Pest Management Guideline.

Monitor caterpillars if they have been a problem in the past:
  • Omnivorous leafroller
  • Grape leaffolder
  • Western grapeleaf skeletonizer

Keep records (example monitoring form PDF).

Monitor sticky traps for glassy-winged sharpshooters:

Other pests or pest damage you may see:

Véraison

(San Joaquin Valley, June to July; Coachella Valley, May)

What should you be doing at this time?
Monitor leafhoppers, spider mites, and mealybugs weekly.
  • Keep records (example monitoring form PDF).
  • Manage if needed according to Grape Pest Management Guideline.
Continue checking pheromone traps weekly for omnivorous leafroller.
Inspect vines for grape mealybug and vine mealybug.
  • Educate field crew to identify and mark vine infestations for treatment.
  • Manage if needed according to Grape Pest Management Guideline.
Monitor sticky traps for glassy-winged sharpshooter.

Mark locations of vines with poor growth for future confirmation and management of abiotic disorders or pests:

  • Bot canker
  • Eutypa dieback
  • Measles
  • Pierce's disease
  • Phylloxera
  • Nematodes
Monitor for Botrytis bunch rot, powdery mildew, and summer bunch rot.
  • Hedge canopy to increase air movement and reduce humidity in the fruit zone.
  • Manage if needed according to Grape Pest Management Guideline.
Monitor caterpillars if they have been a problem in the past:
  • Omnivorous leafroller
  • Grape leaffolder
  • Western grapeleaf skeletonizer

Keep records (example monitoring form PDF).

If necessary, manage birds with netting or scare devices as fruit ripens.
Remove weeds that have escaped treatment before they set seed.
Consider the use of plastic vine covers for late harvest varieties, which are susceptible to Botrytis bunch rot after heavy rain.

Other pests or pest damage you may see:

Harvest

(San Joaquin Valley, late June to early November; Coachella Valley, mid-May to early July)

What should you be doing at this time?
Check fruit at harvest to assess the effectiveness of the current year's IPM program and to determine the needs of next year's program.
  • Note blocks in the vineyard that had problems.
Check sticky traps for glassy-winged sharpshooter.
If necessary, continue managing birds with netting or scare devices.

Postharvest

What should you be doing at this time?
Continue monitoring for vine mealybug on fruit and foliage.
  • Treat if needed according to Grape Pest Management Guideline.
  • If vine mealybug is present, steam-sanitize equipment before moving to uninfested areas.
In the San Joaquin Valley look for European fruit lecanium scales on leaves.
  • Treat if needed just before leaf drop, according to Grape Pest Management Guideline.
Continue to mark and remove vines or cordons infested with diseases such as:
Continue to monitor for western grapeleaf skeletonizer on early harvested varieties.
In the Coachella Valley, sample for nematodes in October if not already done in spring.
Check sticky traps for glassy-winged sharpshooters.
Other pests you may see:

Dormancy

What should you be doing at this time?
In the San Joaquin Valley, sample for nematodes from November to February.
Carry out dormant-season sanitation activities.
  • Prune late in dormancy after rains to reduce wound infections.
  • Destroy prunings of older infested wood to reduce pest sources.
  • Remove dried grape clusters on vines and disc weeds and clusters where orange tortrix or omnivorous leafroller is a problem.
  • In vineyards with a history of branch and twig borers, examine old pruning scars and dead parts of vines for brown frass and wood dust.
  • If you have vine mealybug, steam sanitize equipment before relocating.
Survey weeds to plan a weed management strategy.
  • Record your observations (example survey form PDF).
  • Use records to make herbicide selections in vineyards where sprays are planned.

Pesticide application checklist

When planning for possible pesticide applications in an IPM program, review and complete this checklist to consider practices that minimize environmental and efficacy problems.
  • Choose a pesticide from the UC IPM Pest Management Guidelines for the target pest considering:
  • Select an alternative chemical or nonchemical treatment when risk is high.
    • Choose sprayers and application procedures that keep pesticides on target.
    • Identify and take special care to protect sensitive areas (for example, waterways or riparian areas) surrounding your application site.
    • Review and follow label for pesticide handling, storage, and disposal guidelines.
    • Check and follow restricted entry intervals (REI) and preharvest intervals (PHI).
    • After an application is made, record application date, product used, rate, and location of application. Follow up to confirm that treatment was effective.
  • Consider water management practices (PDF) that reduce pesticide movement off-site:
    • Install an irrigation recirculation or storage and reuse system.
    • Use drip rather than sprinkler or flood irrigation.
    • Limit irrigation to amount required using soil moisture monitoring and evapotranspiration (ET).
    • Consider vegetative filter strips (PDF) or ditches.
    • Redesign inlets into tailwater ditches to reduce erosion.
  • Consider management practices that reduce air quality problems.
    • When possible, choose pesticides that are not in emulsifiable concentrate (EC) form which release volatile organic compounds (VOCs). VOCs react with sunlight to form ozone, a major air pollutant.

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