How to Manage Pests
UC Pest Management Guidelines
In this Guideline:
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
Site Cropping History
- Identify previous crops that are known hosts to alfalfa pests.
Monitor and evaluate alfalfa pest infestations in the
field or neighboring mature alfalfa fields.
- Evaluate yield and quality of past alfalfa varieties grown on this
- Evaluate suitable varieties currently available.
- Topography. Uneven fields may require extensive land leveling for
- 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 (ECe ) 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
UC IPM Pest Management Guidelines: Alfalfa
UC ANR Publication 3430
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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