How to Manage Pests

UC Pest Management Guidelines

HOW TO CHOOSE YOUR FIELD

Choose fields carefully for alfalfa planting. A field’s cropping history is important; alfalfa planted in fields with poor nutrient balance or infested with alfalfa pests, especially weeds, will suffer yield loss.

Identify the crops and vegetation surrounding your alfalfa fields. For example, do they harbor pathogens such as Sclerotinia. Carefully planned cultural practices, including altering planting dates, can reduce losses to certain pests.

Use the information below when selecting fields for alfalfa planting.

Site Cropping History

• Identify previous crops that are known hosts to alfalfa pests.

Current Pests

Monitor and evaluate alfalfa pest infestations in the field or neighboring mature alfalfa fields.

• Weeds. For sites with high populations of weeds not controlled by herbicides labeled for alfalfa, consider rotating to another crop for easier management.
• Sclerotinia. Avoid by planting in February for infestations onsite or in neighboring mature alfalfa fields.
• Weevils. Check for weevils in neighboring fall-planted alfalfa fields.
• Stem nematode.

Alfalfa Varieties (446KB, PDF)

• Evaluate yield and quality of past alfalfa varieties grown on this site.
• Evaluate suitable varieties currently available.

Land Features

• Topography. Uneven fields may require extensive land leveling for proper drainage.
• Drainage. Check site for adequate irrigation and tail-water drainage.
• Water. Evaluate the quantity and quality of available irrigation water at the site.

Check Soil Records or Perform Soil Assays.

• Nutrient balance. Assay for phosphorous and potassium.
• pH. A pH of 6.2 to 7.5 is recommended. Lower pH does not support Rhizobium growth.
• Salinity. Electrical conductivity (EC_e ) should be 2.0 mmhos/cm or less.
• Toxic elements. Check for excess of boron or sodium.
• Soil type. Alfalfa grows successfully on a wide range of soil textures, but sandy loam to clay-loam soils are preferred.
• Soil depth. A site should provide a minimum of 3 feet of unrestricted rooting depth.

IMPORTANT LINKS

• Special weed problems in established alfalfa
• Photos of weeds not controlled by herbicides labeled for alfalfa
• Alfalfa varieties leaflet information
• Crop rotation options to reduce some alfalfa pests
• Alfalfa and Egyptian alfalfa weevil pest management guideline
• Nematode pest management guideline

PDF: You need Adobe Acrobat Reader version 5 or later to view or print this PDF. If this software is not installed on your computer, you can download a free copy of Acrobat Reader.

PUBLICATION

UC IPM Pest Management Guidelines: Alfalfa
UC ANR Publication 3430
General Information
W. M. Canevari, UC Cooperative Extension, San Joaquin County
C. A. Frate, UC Cooperative Extension, Tulare County
P. B. Goodell, Entomology, Kearney Agricultural Center, Parlier
D. H. Putnam, Plant Sciences, UC Davis
C. G. Summers, Entomology, Kearney Agricultural Center, Parlier
R. N. Vargas, UC Cooperative Extension, Madera County

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