Armyworms attack

PERKINS TWP. — Some local residents have recently noticed their lawns turning brown. Perkins Township resident Jim Powers thought his lawn was dying because of hot temperatures and lack of rain. A few other properties in his neighborhood were experiencing the same problem. But the weather was not the case. "Most of the counties in Ohio are experiencing localized hot spots of fall armyworm damage," said David Shetlar, professor emeritus of entomology at Ohio State University. What's happening? The area is experiencing an invasion of fall armyworms, a semi-tropical species that come north each year. The armyworm populations in southern states — from Oklahoma across to North Carolina — have been in an outbreak mode, causing significant damage to field crops and turfgrass the last couple of months. Shetlar said several storm fronts that came to Ohio from the Gulf of Mexico gave a "ride" to fall armyworm females. "We always get some fall armyworm, yellow-striped armyworm and beet armyworms every year. But this massive outbreak of the fall armyworm has been truly exceptional," he said. "I can't remember when we've had this level of an infestation that has damaged so much turf over such a wide area." Another type of armyworm, the common armyworm, is a resident of Ohio and is seen every year, Shetlar said. But common armyworms have been lacking this summer and haven't caused significant damage. Fall armyworms are doing significant damage to lawns. In some cases, they can destroy an entire lawn in two days, said Julie Barnes Foster of Barnes Nursery. Fall armyworms are picky about what they eat. Shetlar said they will most readily feed on bentgrass — that's used primarily on golf courses — Kentucky bluegrass and fine fescues, tall fescues and perennial ryegrasses if these don't have endophytes. Endophytes are a symbiotic fungus that produces toxins that are lethal to the armyworm caterpillars. For whatever reason, the fall armyworms won't eat two common weedy grasses: crabgrass or goosegrass, Shetlar added. In field crops, seedling corn, oats and wheat are preferred hosts, Shetlar said. But fall armyworms are famous for attacking the young ears of developing, more mature corn. They are commonly mistaken for the corn earworm that also attacks corn ears. Fall armyworm adults tend to fly at night, and they are strongly attracted to flowering plants, he said. Oftentimes, the females will lay eggs near where flowering plants are located. "We have noticed several times this season that when there is a major infestation and this army of worms runs out of food, the larger caterpillars will begin eating the smaller caterpillars," Shetlar said. "It's a rather strange survival strategy that ensures that the largest of the surviving caterpillars are able to complete their development." Shetlar believes people will continue to hear about fall armyworms until the first killing frost. The fall armyworm is not capable of surviving freezing winter temperatures. What to do To determine if a spot in your lawn has fall armyworms, Foster recommends filling a watering can with warm water and a tablespoon of dish soap. Dump it on the dead grass to flood the area. If there are fall armyworms, they will come to the surface. The semi-tropical armyworms can have green, brown to black heads with an obvious white, upside-down Y-mark, according to Shetlar. "There is also a lot of luck involved in whether you will be 'hit' or not by these caterpillars," Shetlar said. Out of 50 to 60 properties in his neighborhood, he noticed about five that had some activity. "Homeowners and lawn maintenance professionals just have to keep on the alert for signs of an infestation, like a sudden thinning and browning of the turf," he said. Quick action is needed once activity is detected because the caterpillars eat the turf canopy. That results in the turfgrass plant crowns being exposed and the crowns can "cook" in the direct sun. Shetlar recommends lightly irrigating during the day to cool down the canopy until new leaves emerge and shade the plant crowns. Cooler temperatures will help the damaged turfgrass plants survive. There are many professional and over-the-counter products that can be used to kill the fall armyworms. According to the OSU's Buckeye Yard and Garden Line, directly applying insecticide can be used to protect turfgrass and kill the fall armyworms.