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Fall armyworms in wheat

Fall armyworms in wheat

By: By TIM SMITH Extension director

As you drive around the county, it is easy to see the abundance of volunteer corn in fields. Some of these fields have already been planted in wheat, with others that soon will be. Many were waiting on moisture before planting, and now that this has happened, many acres will be planted once farmers are able to get back in the fields.
There is a concern about larvae on volunteer corn and the likelihood that these larvae will feed on wheat being planted into these situations. It is a good bet that re-growth corn will get fall armyworm, and the larvae on this volunteer corn are indeed fall armyworm (FAW). FAW larvae can play havoc on emerging wheat stand, and you should be concerned about planting wheat if larvae are present on the relatively thick stands of volunteer corn that are present in some fields. If a fast-acting herbicide (e.g., Gramoxone) is applied before or at planting, it is a good bet the larvae will be gone before the wheat comes up. If you spray glyphosate (e.g. RoundUp, assuming it was not RR corn), the corn will be slow to die, and the larvae may move onto the emerging wheat.
I expect some producers are intending to plant at let the frost kill the corn. If this is the case, I would put a pyrethroid like Mustang Max, Karate, Prolex or Baythroid) on at planting. There are some other insecticide options including Lannate LV, Sevin XLR or Tracer. However, the truth is, if you are willing to spray an insecticide, you should consider burning down the corn in advance of planting. This should eliminate the need for insecticide.
There are other pests on volunteer corn that might also affect wheat including aphids and wheat curl mites.
As a rule of thumb, it is best not to have a “green bridge” that allows insects on weeds to move immediately into the next crop planted in the field (in this case wheat).
Published in The Messenger on 10.23.07

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