FROM THE FIELD Fighting Surface-Feeding Insects

With  the onset of summer, green grass covers customers’ lawns across the country. However, now is the time when  attention shifts beneath the blades of green and toward the soil, where insects prepare to feed on luscious lawns.

While a host of turf insects find their nourishment below the thatch layer, they typically are not problematic until late summer. Early summer sees surface-feeding insects, particularly chinch bugs and sod webworms. Understanding these insects, as well as their habits and life cycles, is the key to effectively controlling and protecting your customers’ lawns.

SOD WEBWORMS. Sod webworms are most often identified as they grow into their adult forms, which are as lawn moths. These small, whitish-gray moths are distinctive for the way their wings fold in over each other and for their erratic, zigzag flight pattern. They typically hide deep in a lawn or in nearby shrubs to avoid direct sunlight.

The early nymph form webworms are  most troubling. These critters begin feeding as soon as they hatch, and they are most active at night. Depending on the  species, they will feed either on the crowns of the turf or the blades themselves, and they favor bluegrass and fescue.

How do you know you have a sod webworm-infested lawn? The webworms feed by chewing the turf leaf, and the cumulative damage resembles drought stress, especially as they thin out a lawn. The most telltale sign is the green frass pellets they leave behind as they feed.

CHINCH BUGS. Last year, chinch bug problems seemed more widespread than normal, but that was not actually the case. Instead, they caused more damage thanks in large part to a lack of rainfall in much of the country. Already-weakened turf was no match for the additional abuse. Again, the young nymphs are most problematic due to their aggressive early feeding. When chinch bugs infest a lawn, the signs resemble drought stress as the insects suck the sap out of the individual grass blades. If not controlled, the grass will first turn yellow, then brown and then die.

Chinch bugs come in two different varieties – the hairy chinch bug can be found in northern areas, while the southern chinch bug prefers warmer climates. The cooler, northern weather limits chinch bugs to two generations in a typical year, compared to three or even four in the South.

While ensuring your properties are properly fertilized and irrigated throughout the summer provides the best protection again infestation, a host of products are available for chinch bug control. The host of bifenthrin-based products on the market are traditional favorites.

Chinch bugs overwinter by digging into the thatch and going dormant, and the warming spring temperatures spur them to resume feeding and then mate.  If preventive control is not an option, be sensitive to the pests’ reproduction schedules to prevent additional generations from feeding too long. In the north, late May/early June and August are when hairy chinch bugs reproduce, while the southern chinch bugs favor a quarterly schedule for three or four cycles.

Control products typically carry 30-day residuals. However, be prepared to make multiple applications to achieve the desired control, especially when battling second-generation chinch bugs, which can be quite hardy.

In addition, scout neighboring properties when treating customers’ turf to see if infestations may be simply waiting for their opportunities to spread.

Toorish and Kelley are part of LESCO’s Tech Services Department. They can be reached at techguys@lesco.com or at 800/321-5325 ext. 3150 to answer technical questions.