They love Bermuda lawns, but can attack other varieties as well.
The worrisome creatures hatch larvae deep within the soil. They are most active early and late in the day, spending the hotter hours down near the soil in the shade. Every 2 to 4 days, the larvae hatch beginning a new batch of soldiers trying to destroy your lawn. Be aware, although not present at first glance, the sod could have thousands of the little larvae in the sod just days away from becoming a turf eating machine…..SO DO NOT ASSUME THEY ARE NOT THERE. Keep a constant eye for the first sign of these worms!
If there is any doubt about whether worms are present, pouring soapy water on the grass (1/2 oz. dish washing soap/gallon water) will bring them up quickly. Heavily infested turf will also have visible greenish-black fecal pellets on the soil surface. If not treated, the larvae will continue to reproduce and can move onward in an unbelievable pace of utmost destruction. Army worms get there name because there could be 20 today and 10,000 tomorrow!!!
Treatment: Treat sod immediately on first sign of armyworms!! Spray with chemicals such as liquid “Sevin”. Irrigate before treating to move the armyworms out of the thatch. Treat in late afternoon, when the worms are likely to begin feeding. If possible, mow before you treat and then do not mow for 3 days after treatment.
Please note: “They rarely kill grass.” They are leaf eaters and they will go to wherever there are leaves. New sod is a magnet to army worms because of the clean, nutritious value. They will travel from yard to yard until all grass is consumed. Also, please be aware that these worms can be brought in from shrubs, trees, and pine straw, and can migrate from wooded areas in the vicinity.
The lawn will survive and rejuvenate, because the worms only eat the leaf.