Alfalfa

Year-Round IPM Program

(Reviewed 11/06, updated 11/06)

Established stands

These practices are recommended for a monitoring-based IPM program that reduces water 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 first year with the annual checklist form. For established stands, download the annual checklist form for established stands only. This program covers the major pests that affect fall-planted alfalfa hay in the Sacramento or the San Joaquin valleys. Information about other pests is included in the Alfalfa Pest Management Guidelines.

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

For IPM practices during the preplanting and stand establishment period, see Establishing a stand.

Winter (November through January)

Special issues of concern related to water quality: drift, runoff due to rain.
What should you be doing during this time?
Survey winter weeds December through January.
Determine weed management strategy based on last year's weed population, and consider:
Begin to sample for cowpea aphid in late February.
Monitor for weevils:
  • Look for damage such as chewed leaves or take sweep net samples.
  • Keep records on a weevil monitoring form (PDF).
  • Manage if needed according to Alfalfa Pest Management Guidelines.
Look for signs of vertebrates.

Spring

Special issues of concern related to water quality: runoff due to rain, irrigation or drift.
What should you be doing during this time?
Time harvests by evaluating:

Consider border-strip harvesting to conserve natural enemies.

Determine appropriate weed management strategies based on last summer’s weed populations. Note any special weed problems such as:
  • Grasses
  • Nutsedge
  • Dodder

Manage if needed according to Alfalfa Pest Management Guidelines.

Look for signs of vertebrates.
Monitor for weevils. Consider early harvest if Egyptian alfalfa weevil is a problem in your field.
  • Keep records on a weevil monitoring form (PDF).
  • Manage if needed according to Alfalfa Pest Management Guidelines.
Monitor aphids and their natural enemies. Consider border or strip harvest to preserve natural enemies.
  • Keep records on an aphid monitoring form (PDF).
  • Manage if needed according to Alfalfa Pest Management Guidelines.
Look for cutworms if damage is apparent.
  • Manage if needed according to Alfalfa Pest Management Guidelines.
If you see thrips, no treatment is needed.
Watch for signs of diseases and nematodes.
Consider field sanitation:
  • Harvest disease- and nematode-free fields before infested fields.
  • Avoid moving contaminated farm machinery or livestock from a field infested with nematodes or disease to a clean field.

Summer

Special issues of concern related to water quality: drift, runoff due to irrigation.
What should you be doing during this time?
Time harvests by evaluating:
Survey weeds, especially weedy grasses.
  • Keep records on a weed survey form (PDF) for next spring’s weed management decisions.
Monitor cowpea and spotted alfalfa aphids. Consider border or strip harvest to preserve natural enemies.
  • Keep records on a monitoring form (PDF).
  • Manage if needed according to Alfalfa Pest Management Guidelines.
Monitor caterpillars and armyworms. Consider early harvest to reduce losses.
Monitor leafhoppers at the first sign of damage. Consider early harvest to reduce losses.
  • Keep records on a monitoring form (PDF).
  • Manage if needed according to Alfalfa Pest Management Guidelines.
Look for cutworms if damage is apparent.
  • Manage if needed according to Alfalfa Pest Management Guidelines.
Watch for signs of diseases and disorders.
Keep records of other invertebrates.
Consider field sanitation:
  • Harvest disease- and nematode-free fields before infested fields.
  • Avoid moving contaminated farm machinery or livestock from a field infested with nematodes or disease to a clean field.

Fall

Special issues of concern related to water quality: drift, runoff due to rain, irrigation.
What should you be doing during this time?
Time harvests by evaluating pest problems.
Survey weeds in September just after the alfalfa is cut.
Monitor aphids and their natural enemies.
  • Keep records on a monitoring form (PDF).
  • Treat if needed according to Alfalfa Pest Management Guidelines.
Monitor caterpillars. Consider early harvest to reduce losses.
  • Keep records on a monitoring form (PDF).
  • Manage if needed according to Alfalfa Pest Management Guidelines.
Consider field sanitation:
  • Harvest disease- and nematode-free fields before infested fields.
  • Avoid moving contaminated farm machinery or livestock from a field infested with nematodes or disease to a clean field.

For IPM practices during the preplanting and stand establishment period, see Establishing a stand.

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.
    • Avoid spraying areas of bare soil, such as weevil-damaged areas, with pesticides prone to cause water quality problems; consider overseeding these areas with grasses.
    • 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.
    • Be aware of reentry times and pre- and postharvest intervals.
    • 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 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 ET.
    • Consider vegetative filter strips or ditches (PDF).
    • Redesign inlets into tailwater ditches to reduce erosion. Ditches should not be lower than furrows.

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Statewide IPM Program, Agriculture and Natural Resources, University of California
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