Alfalfa

Year-Round IPM Program

(Reviewed 11/06, updated 11/06)

Planting and establishing a stand

Stand establishment is the most critical single factor affecting successful IPM strategies in alfalfa. Follow the practices below to establish and maintain a healthy vigorous stand that resists pest problems.

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 year with the annual checklist form. 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 in established alfalfa, see Established stands.

Preplant

Special issues of concern related to water quality: drift, runoff due to rain.
What should you be doing during this time?
Select your field, considering:
  • Pest history, especially weeds.
  • Current crops and pest problems.
  • Surrounding crops and vegetation.
  • Sclerotinia in neighboring mature fields.
  • Stem and crown rot (white mold).
  • Soil conditions.
Prepare the field for planting by taking into account potential for drainage and run-off problems.
Manage weeds with preplant herbicides if necessary.
Consider crop rotation to minimize, weeds, diseases and nematodes.
Select varieties that are tolerant or resistant to known problem pests.
Select seeds, considering:
  • Use of weed free certified alfalfa seed.
  • Seed treatment for suspected field pathogens or if planting at suboptimal time.
  • Rhizobium treatment if alfalfa has not grown in the field for the last 5 to 10 (or more) years.

Stand establishment

Special issues of concern related to water quality: drift, runoff due to rain, irrigation.
What should you be doing during this time?
Plant seed, following proper timing, depth, and seedling rates.
  • Plant in early fall for best results.
  • Plant 1/4" deep, depending on soil type.
  • Use a higher seed rate for organic production.
Consider interplanting oats to:
  • Reduce weed competition
  • Increase the first forage yield
  • Reduce erosion
Survey weeds when the crop germinates.

Watch for seedling pests:

  • Damping off and other seedling diseases
  • Sclerotinia stem and crown rot (white mold)
  • Downy mildew
  • Aphids
  • Cutworms
  • Garden symphylans

Keep records on a map of the field (PDF).

Growth to first cutting

Special issues of concern related to water quality: drift, runoff due to rain, irrigation.
What should you be doing during this time?
Look for signs of alfalfa weevils, such as chewed leaves.
  • Manage if needed according to Alfalfa Pest Management Guidelines.
Monitor for aphids and their natural enemies.
  • Keep records on an aphid monitoring form (PDF).
  • Manage if needed according to Alfalfa Pest Management Guidelines.
Check soil moisture.
Survey weeds to plan weed management strategy.
  • Keep records on a weed survey form (PDF).
  • Treat with postemergent herbicide, if needed according to Alfalfa Pest Management Guidelines.
Time first cutting carefully to maintain stand vigor.
  • Make sure rooting depth is at least 14 inches and the crown is formed.
  • Check soil moisture status considering compaction by heavy equipment.
Identify other diseases you may see.
  • Sclerotinia
  • Downy mildew
  • Common leaf spot

For IPM practices in already established alfalfa, see Established stands.

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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