Management of Forage Quality In Strip-Cut Alfalfa

The Issue

Lygus bugs prefer alfalfa to many other crops, but don't damage it. Alfalfa can sustain high populations of lygus, but when the fields are cut every month the pest moves into neighboring susceptible crops. Retaining lygus populations in alfalfa fields is the centerpiece of a promising regional pest management strategy. This involves leaving strips of uncut alfalfa which act as a temporary habitat for lygus bugs, thus limiting their movement out of the field. The method works well, but growers are concerned about the effect that the strips of more mature alfalfa have on hay quality and marketability.

What Has ANR Done?

A strip cutting trial has been conducted for the past three years. At each of three cuttings during each production season, hay bales were produced with various mixtures of old and new growth alfalfa, ranging from no old growth to 100%. Bale compositions were created during swathing and raking.

Chemical analysis as well as visual inspection detected reduced quality of bales containing 14%, 25% or 50% old hay. However, bales containing only 7% old hay were similar in quality and appearance to bales with 100% new hay.

When quality is lower, the hay value is less and the markets may be limited. For example, dairy hay must meet a very high standard of quality. Blended hay with more than 7% old hay would not be acceptable to this market, but could be used in the beef or horse markets.

The Payoff

Growers can manage strip cutting to maximize quality

Forty-five percent of cotton growers surveyed said they use strip or block cutting of alfalfa as part of their pest management program. Using the information developed by UCCE, they can now make informed decisions how to manage the hay in the uncut strips. They may choose to blend it with the new growth and handle the lot as a single unit, or they may segregate out the bales containing the old hay. By having a much better idea of the reduced quality that will result from blending old hay with the new, growers may be more willing to use this strategy to limit lygus migration from alfalfa hay fields.

Contact

Supporting Unit:

Fresno County and Kearney Agricultural Center
 
Shannon Mueller, UCCE Agronomy Farm Advisor,1720 S. Maple Avenue, Fresno, CA 93702
(559) 456-7261 scmueller@ucdavis.edu

Peter B. Goodell, IPM Advisor, UC Statewide IPM, Kearney Agricultural Center, 9240 S. Riverbend Avenue, Parlier, CA 93648 (559)646-6500

Charles G. Summers, Department of Entomology, UC Davis and Kearney Agricultural Center, 9240 S. Riverbend Avenue, Parlier, CA 93648, (559)646-6500