They are back! Since a little before Labor Day, spotty reports of Fall Armyworms have come into my office from around the county. These pesky insects make an annual migration north from the valley of Texas and usually make it here around the first to middle of September. Unlike grasshoppers, armyworms will have several generations per year, which makes their control more difficult.
Before attempting control, ask yourself the following questions: Do I have a serious problem? and Do I need the forage?
If you can go out and count more than 3 of the 'worms' per square foot of pasture then you have a population that is at or above the economic treatment threshold (which means that you will save enough pasture to justify the $7 to $10 per acre for the treatment). So, if you have less than 3 per square foot, save the money and do not spray right now. To get an accurate estimate of the population, walk randomly in the pasture and count 'worms' on at least 10 different square foot areas. If the average of these counts is 3 or more, then you are at the treatment threshold and should ask yourself whether or not you need the forage.
If you have made all the hay you need for the year, or are stocked at a really light rate of livestock, then you might not want to spray. If you have recently fertilized a hay field and are counting on that cutting for the winter, then spray. Also, if you are planting winter pastures, then you will want to keep a close watch on them as they come up and be prepared to spray these new pastures in a hurry to protect your investment. Otherwise, you might want to sit this one out.
A dry fall might make pasture losses worse, while a wet fall might help overcome any losses experienced now. An early frost/freeze event will shut their activity down in our area for the year.
If you would like to learn more about Fall Armyworms, or see a list of chemicals labeled for their control, visit http://smith-tx.tamu.edu./publications/fallarmywormfactsheet2005.pdf.
Always read the label before use and remember to adhere to grazing/haying restrictions following spraying and the total amount of product allowed per acre per year.
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