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Animal Science and Forages > ASF Blog > Posts > Watch for Fall Armyworms Especially in Small Grains Planted Early for Forage, Wildlife, or Cover Crops

It would be nice if we could be done with fall armyworms for the year. But they will be around until the first hard frost. Please keep looking for fall armyworms in your forage crops. On the bright side, as the weather cools down it will take longer for the armyworms to complete a generation.

I am especially concerned about small grains that are planted early for forage, wildlife, or cover crops, such as wheat, oats, and rye. These small grains should be scouted from emergence through the first hard frost. These newly planted grains should be scouted frequently, at least once a week, by visually examining the plants. A sweep net can be used as a first detection tool in overseeded areas where the perennial grass is still green. The sweep net is not useful in row crop areas until the wheat gets about 4 inches tall. On the smaller plants, look for signs of something feeding on the plants. Also look for the small caterpillars under any crop debris in the field. They tend to hide during the day. Scouting early in the morning or late in the increases the chances of seeing the caterpillars on the foliage. Pay close attention to any bare spots in the field, which could be a sign that something isdefoliating the seedling grain.

A reasonable threshold to use in fall planted small grains is 1 caterpillar per square foot. This is adjusted downward from the 2-3 per square foot threshold we use for established grass forages.

Insecticides are available to control the fall armyworms on wheat and other small grains. However, they are not all the same as those used on grass forages. So here is the link to the small grain IPM Guide: Small Grain IPM Guide - IPM-0458. The insecticides recommended for use for fall armyworms are listed in Table 5 starting on page 7. Only one trade name for each active ingredient is listed in Table 5. So you may need to check Table 6, which starts on page 12. This table contains a list of most of the generic insecticides. Some insecticides labeled on small grains are not labeled for perennial grass pastures and hayfields. So in situations where the small grain has been overseeded into perennial grass sod,be sure to pickan insecticide thatis alsolabelled for perennial grass forages (see 2016 Insect and Weed Control Recommendations - IPM-0028). Remember, it is not legal to apply an insecticide to a site unless that site is listed on the label.

As with our summer forages, choosing an insecticide with a longer residual will provide more protection from fall armyworms. The insecticides labeled on small grains that have the longest residual for fall armyworm control are Prevathon (active ingredient chlorantraniliprole) and Besiege (active ingredients chlorantraniliprole and lambda-cyhalothrin).

Early planted small grains are also subject to infestation by Hessian fly and by aphids that spread Barley yellow dwarf and cereal yellow dwarf virus. I did a webinar yesterday that discusses management strategies for these problems, as well as for fall armyworm.

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Just as a reminder, the recommended planting dates for wheat in Alabama are listed below.


North Alabama Central Alabama South Alabama
Grain

Oct. 15 - Nov. 10

Oct. 15 - Nov. 15

Nov. 15 - Dec. 1

Forage Plus Grain

Sept. 15 - Nov. 1

Sept. 15 - Nov. 1

Oct. 1 - Nov. 15

Forage

Aug. 25 - Sept. 10

Sept. 1 - Sept. 15

Sept. 15 - Sept. 30

Cover Crops

Sept. 1 - Nov. 1

Sept. 15 - Nov. 1

Sept. 15 - Nov. 15

Wildlife Planting

Aug. 15 - Nov. 1

Aug. 15 - Nov. 1

Aug. 15 -Nov. 1

As always, here are some helpful links about fall armyworm:

You can find the latest map on where damaging populations of fall armyworms have been found in several different ways:

  1. You can follow this direct link to the ArcGIS map site
  2. There is a direct link to the page from the Alabama Forages homepage underneath the *NEW* section.
  3. You can find a link to the map, as well as helpful information related to Fall Armyworm underneath the "Fall Armyworm" section of the Forages Insect Pest Management page.

Please let me know if you find them so we can keep updating the map.

Here are the individual links to various fall armyworm resources:

Instructions on how to use a sweep net to look for fall armyworm:

 

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Insect sweep nets can be purchased at various farm and forestry supply stores.

Please let me know if you find fall armyworms in your Alabama forage grasses.

Kathy Flanders

flandkl@auburn.edu


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