A Fall Armyworm (a very hungry caterpillar)
A Very Hungry Caterpillar (not a Fall Armyworm)
What’s a Fall Armyworm?
Last week, Dr. Donald Lewis, Dr. Adam Thoms, and Dr. Nick Christians from Iowa State addressed a turf field day crowd regarding a very rare pest that has been confirmed in Iowa. Combined, these three men have almost a hundred years of turf experience between them, and they were all in agreement that they can count on one hand the times Fall Armyworm has been a nuisance for Iowa lawns in their careers.
In short, Fall Armyworms are typically found in the south, but some late-in-the-season tropical storms and hurricanes just happened to coincide with a life cycle that was surging in the south and it brought new winged friends (the adult moths) to our northern lawns.
Ewwww! Gross! How Do We Stop It!?!?
Fall Armyworm damage. This damage happened within 48 hours of the first caterpillar sighting in the Cedar Rapids lawn.
There is good news: They cannot survive our winters. So this is very much a one-and-done kind of issue for many of us.
But there is bad news too: They can eat all of the green material of an average-sized lawn in as little as 72 hours (see photo of damage in Cedar Rapids lawn). I will also post a link in the comments to a news story from Ohio local news about Fall Armyworms in lawns out there.
Should you be concerned? Statistically speaking, it is unlikely these pests will be everywhere in Iowa. But they have been confirmed in Cedar Rapids, so you should remain vigilant and watch for the sudden appearance of dead-looking patches in your lawn that were not there the day before and that are growing aggressively.
If you suspect you might have Fall Armyworms in your lawn, you really need to confirm the caterpillar’s presence before running out to get a spray that will kill them. Using insecticides without confirmation of what you are trying to control is not a good practice. Mix up a 5-gallon bucket of soapy water and dump it near the affected spot. The soapy water will drive the caterpillars to the surface within a few minutes if they are present. Keep in mind that seeing a single caterpillar is not cause for great concern. The pest needs large numbers to clear-cut a lawn.
Once confirmed, visit your local hardware store for an insecticide labeled for Fall Armyworms and follow the directions closely for application.
Feeling a little nervous? How about I finish this little email with another piece of good news? These very hungry caterpillars only eat the plant material above ground in your lawn, which means that 13-13-13 and irrigation should help the area to recover quickly, but it will be an eyesore for a bit! Oh! And did I mention they don't like cold?? Cooler temps are coming (someday) to our rescue...
So at least we don't have to dump soapy water on our lawn for too much longer... :)