Citrus (Central Valley)

Year-Round IPM Program

(Reviewed 7/08, updated 9/08, corrected 6/13)

These practices are recommended for a monitoring-based IPM program that reduces water and air quality problems related to pesticide use. Track your progress through the year using this 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 form for information on how to minimize air and water quality problems.

This year-round IPM program covers major pests of citrus grown in California's Central Valley. Details on carrying out each practice, information on additional pests, and additional copies of this form are available from the UC IPM Pest Management Guidelines: Citrus.

Prebloom (January through March)

Special issues of concern related to environmental quality: Drift and runoff.
What should you be doing during this period?
Monitor California red scale males using pheromone-baited sticky traps (March through October), plus additional methods depending on the situation.
Look for spider mites and other mites.

Manage if needed according to Citrus Pest Management Guidelines.

Look for cottony cushion scale and predatory vedalia beetles (March through July).
  • Collect and relocate vedalia to cottony cushion scale-infested orchards if vedalia have not arrived by the end of March.
Look for other pests and their damage to fruit or damage to leaves and twigs, especially:

Manage if needed according to Citrus Pest Management Guidelines.

Look for brown garden snail.
  • Collect and relocate predatory decollate snails if they were not previously found in the orchard, brown garden snail has been a problem, and decollate introductions are permitted in your county.

Manage if needed according to Citrus Pest Management Guidelines.

Look for diseases that cause symptoms on fruit, leaves and twigs, and on limbs, trunks, and roots, especially:

Record the date and location of problem trees or sites. Manage if needed according to Citrus Pest Management Guidelines.

Survey winter weeds. Identify common winter broadleaves and grasses.
  • Keep records (example winter weed survey formPDF), survey at least twice annually (during late winter and in summer).

Manage vegetation if needed according to Citrus Pest Management Guidelines.

Look for vertebrates, especially ground squirrels, pocket gophers, rabbits, and roof rats. Manage if needed, according to Citrus Pest Management Guideliness.
Provide proper cultural care and good growing conditions to improve tree health and fruit yield, including:
  • Fertilize if needed.
  • Inspect irrigation systems by late winter and irrigate if rainfall has been insufficient.
  • Provide frost protection (PDF) when cold threatens.
  • Prune if needed, but only after frost is no longer a threat.
Harvest mature fruit in coordination with other management activities to ensure good postharvest fruit quality and food safety (PDF).
  • Educate and supervise workers regarding fruit-handling Best Management Practices (BMPs)
  • Inspect fruit quality before bins are moved from the picking site to identify grove areas where management practices need improvement.

Bloom (April)

Special issues of concern related to environmental quality: Drift, runoff, and volatile organic compounds (VOCs).
What should you be doing during this period?
Monitor California red scale males (March through October) plus additional methods depending on the situation.
Look for spider mites and other mites.

Manage if needed according to Citrus Pest Management Guidelines.

Look for cottony cushion scale and predatory vedalia beetles.
  • Collect and relocate vedalia to cottony cushion scale-infested orchards if vedalia have not arrived on their own during April.

Look for other pests and their damage to fruit or damage to leaves and twigs, especially:

Manage if needed according to Citrus Pest Management Guidelines.

Look for brown garden snail.
  • Collect and relocate predatory decollate snails if they were not previously found in the orchard, brown garden snail has been a problem, and decollate introductions are permitted in your county.

Manage if needed according to Citrus Pest Management Guidelines.

Manage pesticides to avoid killing honey bees.
Look for diseases that cause symptoms on fruit, leaves and twigs, and on limbs, trunks, and roots, especially:

Record the date and location of problem trees or sites. Manage if needed according to Citrus Pest Management Guidelines.

Provide proper cultural care and good growing conditions to improve tree health and fruit yield, including:
  • Fertilize if needed.
  • Irrigate and adjust scheduling to meet trees’ varying water needs.
  • Prune if needed.
Harvest mature fruit in coordination with other management activities to ensure good postharvest fruit quality and food safety.
  • Educate and supervise workers regarding fruit-handling Best Management Practices (BMPs)
  • Inspect fruit quality before bins are moved from the picking site to identify grove areas where management practices need improvement.

Petal fall (late April through May)

Special issues of concern related to environmental quality: Drift, runoff, volatile organic compounds (VOCs).
What should you be doing during this period?
Monitor fruit for immature citrus thrips (late April through June, or through October on lemon).

Manage if needed according to Citrus Pest Management Guidelines.

Monitor California red scale males using pheromone-baited sticky traps (March through October), plus additional methods depending on the situation.

Look for spider mites and other mites.

Manage if needed according to Citrus Pest Management Guidelines.

Monitor cottony cushion scale (May) to see if the vedalia beetle is providing biological control. It is too late to relocate vedalia. If threshold is exceeded, manage later according to Citrus Pest Management Guidelines.
Examine twigs for citricola scale females to alert you whether management later may be needed.

Look for other pests and their damage to fruit or damage to leaves and twigs, especially:

Manage if needed according to Citrus Pest Management Guidelines.

Look for brown garden snail.
  • Heading into warm weather and relocation of decollates is not advised.

Manage if needed according to Citrus Pest Management Guidelines.

Manage pesticides to avoid killing honey bees.
Look for diseases that cause symptoms on fruit, leaves and twigs, and on limbs, trunks, and roots, especially:

Record the date and location of problem trees or sites. Manage if needed according to Citrus Pest Management Guidelines.

Survey weeds. Manage vegetation if needed according to Citrus Pest Management Guidelines.
Look for vertebrates, especially ground squirrels, pocket gophers, rabbits, and roof rats. Manage if needed.
Provide proper cultural care and good growing conditions to improve tree health and fruit yield, including:
  • Fertilize if needed.
  • Irrigate and adjust scheduling to meet trees’ varying water needs.
  • Prune if needed, such as removing dead twigs and branches to reduce bacterial blast (citrus blast) inoculum.
Determine whether application of plant growth regulator is warranted, such as in mandarins.
Harvest mature fruit in coordination with other management activities to ensure good postharvest fruit quality and food safety.
  • Educate and supervise workers regarding fruit-handling Best Management Practices (BMP).
  • Inspect fruit quality before bins are moved from the picking site to identify grove areas where management practices need improvement.

Fruit development (June through September)

Special issues of concern related to water quality:
Insecticide application, fungicide application, drift, runoff due to irrigation.
What should you be doing during this period?
Monitor California red scale males using pheromone-baited sticky traps, plus additional methods depending on the situation.
Monitor fruit for immature citrus thrips (late April through June).

Manage if needed according to Citrus Pest Management Guidelines.

Monitor leaves for citricola scale nymphs (August-September).

Manage if needed according to Citrus Pest Management Guidelines.

If monitoring for cottony cushion scale adult females in May showed that the threshold was exceeded, manage according to Citrus Pest Management Guidelines.
Look for citrus peelminer and examine fruit for its damage.
  • If susceptible variety of citrus, manage according to Citrus Pest Management Guidelines.
Monitor (August through November) for bean thrips in navel oranges that may be exported to Australia. Plan ahead by ordering monitoring traps.
  • Check for revisions to regulatory export protocol, currently:  adult trapping and cutting fruit preharvest and at the packinghouse.
  • If trapping, learn to distinguish bean thrips from other thrips species caught in sticky traps.
Look for other pests and their damage to fruit or damage to leaves and twigs, especially:

Manage if needed according to Citrus Pest Management Guidelines.

Look for diseases that cause symptoms on fruit, leaves and twigs, and on limbs, trunks, and roots, especially:

Record the date and location of problem trees or sites. Manage if needed according to Citrus Pest Management Guidelines.

Survey summer weeds. Identify common summer broadleaves and grasses and sedges.

Manage vegetation if needed according to Citrus Pest Management Guidelines.

Look for vertebrates, especially ground squirrels, pocket gophers, rabbits, and roof rats. Manage if needed.
Provide proper cultural care and good growing conditions to improve tree health and fruit yield, including:
  • Sample leaf nutrient levels at least once mid-August through October. Fertilize if needed.
  • Irrigate and adjust scheduling to meet trees' varying water needs.
  • Prune if needed.

Fall (October through December)

Special issues of concern related to environmental quality:
Drift, runoff, and volatile organic compounds (VOCs).
What should you be doing during this period?
Monitor California red scale males using pheromone-baited sticky traps (March through October), plus additional methods depending on the situation.
Monitor (August through November) for bean thrips in navel oranges that may be exported to Australia.
Look for citrus leafminer (June through November) and citrus peelminer. Manage if needed according to Citrus Pest Management Guidelines.

Look for other pests and their damage to fruit or damage to leaves and twigs, especially:

Manage if needed according to Citrus Pest Management Guidelines.

Look for diseases that cause symptoms on fruit, leaves and twigs, and on limbs, trunks, and roots, especially:

Record the date and location of problem trees or sites. Manage if needed according to Citrus Pest Management Guidelines.

Survey weeds. Manage vegetation if needed according to Citrus Pest Management Guidelines.
Determine whether preventive application of certain materials are warranted including:
  • Fruit rot, rind disorder, and twig blight (bacterial blast) protectants for diseases listed above.
  • Plant growth regulator to reduce fruit drop.
  • Whitewash to preserve fruit quality and to reduce fruit drop and sunburn.

Treat if warranted according to Citrus Pest Management Guidelines.

Provide proper cultural care and good growing conditions to improve tree health and fruit yield, including:
  • Sample leaf nutrient levels at least once mid-August through October.
  • Fertilize if needed.
  • Irrigate and adjust scheduling to meet trees' varying water needs.
  • Provide frost protection (PDF) when cold threatens.
Harvest mature fruit in coordination with other management activities to ensure good postharvest fruit quality and food safety.
  • Educate and supervise workers regarding fruit-handling Best Management Practices (BMPs)
  • Inspect fruit quality before bins are moved from the picking site to identify grove areas where management practices need improvement.

Pesticide application checklist

When planning for possible pesticide applications in an IPM program, consult the Pest Management Guidelines, and review and complete this checklist to consider practices that minimize environmental and efficacy problems.

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