By Linda Geist
By August, most zoysiagrass lawns recover from earlier droughtlike conditions and bugs go to work.
Brown patches of zoysia that are severe along lawn edges such as concrete driveways and sidewalks may indicate chinch bug damage, says University of Missouri Extension turf specialist Lee Miller.
The small, black chinch bugs scatter when homeowners pull damaged zoysia for a closer look. The bugs suck plant juices from leaves and stems.
Lawn owners may see solid, not patchy, areas of damage. Miller considers chinch bugs the most damaging pest in zoysiagrass during the summer months.
Follow label instructions on a curative insecticide using a sprayable, or hose-end application method, Miller says. Apply to the affected area and a margin of 3-5 feet around its perimeter. Chinch bugs appear sporadically. Routine application of preventative insecticide is not warranted, he says.
Billbugs are an emerging pest causing havoc in Missouri lawns. They are more elusive than chinch bugs, Miller says. Adults are reddish brown-black, half an inch long and have a curved snout. They roam at night and in early morning hours.
Their small, legless grubs are about a half-inch long and do the most damage, feeding on zoysiagrass roots after hatching within the plant and eating their way out. Billbug damage starts sporadically in small patches. Eventually, it resembles drought damage, winter dormancy or damage from other root-feeding insects.
Monitor for these pests with pitfall traps in the lawn, Miller says. Dig a few holes and place plastic cups level to the soil surface. Adults fall into the cup overnight. Scouting for the grubs by digging up sections of affected turf may work.
Apply a long-lasting insecticide on lawns with a documented history of billbug damage in late May or early June. Follow insecticide label instructions carefully, Miller says, particularly in regards to protecting nontarget insect pollinators.