Thursday, June 14, 2018

Alfalfa Growers Can Make the Cut as Good Neighbors to Valley Cotton Farmers

American author Emily Post espoused about the importance of proper etiquette during the 20th century. These words certainly ring true in farm country: “To do exactly as your neighbors do is the only sensible rule.”

In our last post, we reported field scout Damien Jelen started to find lygus bugs in cotton fields, a habitat that these pests don’t find attractive. However, lygus do love to live in nearby alfalfa fields. But alfalfa harvesting drove them out to find a new landing spot in adjacent cotton fields, which are starting to develop their buds.

Harvesting alfalfa will disturb the habitat for lygus bugs.
 Damien said he hadn’t seen growers leaving uncut strips of alfalfa as a habitat for lygus. This practice is a neighborly thing to do to keep this pest from threatening the developing cotton squares.
Alfalfa is harvested many times during the season – on average about once a month. That means lygus can be on the move roughly every 30 days.

By leaving uncut strips of alfalfa during harvest, lygus will flock to this habitat and stay there until the next irrigation cycle. The bugs will then go back to the larger alfalfa field as the plants start growing again.

A grower leaves uncut strip of alfalfa grown adjacent to cotton.
UC Integrated Pest Management advisers say leaving uncut strips is vital from June to July because that time period is a crucial stage for cotton development.

Here are strip-cutting tips from UC IPM:

  •         Leave a 10- to 14-foot wide uncut strip adjacent to every other irrigation border (or levee). At the subsequent harvest, these strips are cut with half of the alfalfa strip going into one windrow and the other half going into a second windrow to give a 50:50 blend of new and old hay. These windrows are then each combined with a windrow of newly cut (100 percent new) alfalfa making a blend of 25 percent old hay and 75 percent new hay. This technique minimizes quality problems from the older hay. Specific blends of old and new hay have been found not to significantly impact forage quality compared to 100 percent new growth alfalfa in most cases.
  •         At the following cutting, uncut strips are left adjacent to the alternate irrigation borders. As an alternative, uncut strips of alfalfa may be left adjacent to the crop to be protected, such as cotton or dry beans.

This practice should be followed for alfalfa fields that are within a two mile radius of a cotton field. Lygus bugs can easily go that far after their habitat is disrupted.

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