Most of my social interaction now takes place at the “Y” and the grocery store.

Those were the places I learned of the recent invasion of armyworms into some local lawns.

We never know which year is going to be favored by armyworms, but rainy spells in August or September increase the odds.

Yeah, we had that this time.

As with plants, insect common names are whatever people wherever choose to call certain species.

Ditto for “worm” instead of “caterpillar.” Both words are used for the larva stage of various species of the insect order Lepidoptera, i.e. all the moths and butterflies.

In this locale three species of the Spodoptera genus of moths are called “armyworms.” The one known to eat lawn grass profusely is the fall armyworm, S.frugiperda. The other two are the yellow-striped armyworm and the beet armyworm, neither of which you will likely encounter if you don’t raise cotton or soybeans. Fall armyworms, henceforth just plain “armyworms,” are fairly easy to identify when they are in that one to two inches long grown larvae stage. The body is any shade of green to gray to nearly black with stripes. The telltale sign is the head, which will be some shade of orange. Look the bug square in the eyes and note the inverted “Y” right smack on the face. You’ve got an armyworm, so-called because they show up in large groups that march across the yard or hayfield eating away.

Absent a very mild winter, armyworm moths fly in from further south during the warm season because the species in not very cold tolerant.

They increase in numbers exponentially as they migrate because it only takes a month or so for the moth-to-egg-to-worm-to-pupa-to-moth cycle.

The plant-eating worm stage feeds for about two weeks. And they feed at night, meaning you won’t find the “army” marching and eating during most of the day. Two things to look for: areas of yellowed or brown grass and frass, the correct and polite word for caterpillar manure. Last night’s frass might still be green, but it turns black fairly quickly. Lots of worms always leave lots of frass. While the big, fat 10-day-old ones eat the most each day, those only have another couple of days to eat while the tiny, young ones have nearly two weeks of dining ahead.

In a perfect world, the numerous natural enemies of armyworms would hold down the headcount.  These enemies include birds, parasitic wasps and flies and diseases.  But sometimes armyworm damage gets bad enough for control measures.

Organic insecticides like Bacillus thuringiensis and neem oil control the younger, smaller worms but they don’t have much residual effect a couple of days after treatment. The low impact spinosad insecticide is an option and there are several effective standby chemical products including Sevin and permethrin. If you decide to treat, act early because the worms have moved on once they’ve eaten your grass. Use a liquid spray.  Granules and dust are not much help for this bug problem.

Terry Rector is a spokesman for the Warren County Soil and Water Conservation District.