Insect management with insecticides

Scouting: Scout for adult activity in mid-July to mid-August by scouting nearby foliage and/or use black light traps for European chafers. Scout for larvae in late summer or early spring with soil samples. Check the root/thatch interface for presence of grubs in late July to late August.

Treatment: Treat when adults are laying eggs (mid-June to early August) if using a neonicotinoid. Treat between mid-August and mid-September to moist soil if grub population averages at least 5 to 10 grubs per square foot if using an intermediate or fast-acting material. Water in (at least 0.25”) immediately after application, but avoid puddling. If population was not controlled in late summer, apply spring control as soon as grubs are near surface (normally in April). Note that some materials have been inconsistent while others have performed consistently well over the years.

Scouting: Scout for adult activity in mid- to late April with soapy flush. Monitor for larval activity in late May through June with soil samples, flotation, and visual inspection of thatch layer or collect samples, submerge in saline solution.

Treatment: When targeting adults, treat between Forsythia and flowering dogwood “full bloom” (usually late April to mid-May). Treat for second generation if necessary during first two weeks of July. Water lightly (0.05” to 0.1”). Most applications are best targeted against adults as they begin to lay eggs or against young larvae. When targeting larvae, treat at Rhododendron catawbiense full bloom. Many annual bluegrass weevil (ABW) populations in the Northeast have developed resistance to pyrethroids. While not every population is resistant, golf course superintendents should try to minimize their reliance on pyrethroids whenever possible. Cultural strategies that may help reduce larval populations or minimize damage include converting Poa annua to creeping bentgrass, raising the height of cut where possible, and removing pine litter from nearby white pines. Monitor the areas where ABW are active and target larvae with one of the larval treatments as soon as they are observed.

Scouting: Look for adults, sometimes in very large numbers, on putting greens in April (or use a soapy flush to force them to the surface). Large numbers of adults do not necessarily lead to heavy grub populations. Monitor for grubs from mid-May through mid-August by soil sampling.

Treatment: If treating for adults (before egg laying), apply Dursban or a pyrethroid between Forsythia full bloom and dogwood full bloom, (late April to mid-May) and again two weeks later. Water in lightly (0.05” to 0.1”). Use this approach only in areas where BTA populations have been unusually high in previous years, to avoid treating areas that do not have populations high enough to warrant control. If treating for larvae, apply a material which will penetrate the thatch when horse chestnut or Van Houette spirea are in full bloom, (usually early June). Water in with at least 0.15” to 0.3” of water immediately after application. Imidacloprid or chlothianidin can be applied preventively, but should not be applied earlier than early June if white grubs are also a problem.

Scouting: Scout for adult activity in May and early June, for immature stages throughout summer. In addition, chinch bugs move steadily in the thatch and can be seen by using fingers to spread the turf.

Treatment: Populations are commonly highest in fine fescues and turf stands with thick thatch. Use endophyte containing cultivars when available; avoid drought conditions. Apply in June; water in lightly (less than 0.1”) after application. In some cases, a second application two to three weeks later may be needed.

Scouting: Monitor adult activity with black light traps. Apply insecticides two to three weeks after peak flights. Scout for caterpillars (late in the day or early in the morning) with soapy flushes.

Treatment: Most cutworms are nocturnal, so treatments are most effective if applied late in the day. Water lightly (less than 0.10”). On golf courses inspect aerification holes throughout summer. Damage often becomes most noticeable shortly after aerification, particularly in late summer. Apply two to three weeks after peak moth flight.

Scouting: Monitor adult activity by inspecting turf surface at twilight looking for small “tube moths” flitting just above the canopy. Scout for caterpillars with soapy flushes.

Treatment: Check for sod webworm activity: look for small green pellets in upper thatch or flush an area with soapy water. Watch for webworm moths flying at twilight. Apply controls 10 to 14 days after number of moths declines sharply. Repeat applications may be necessary. Treat as late in day as possible. Water lightly (0.10”); do not mow for one to three days after application.

Scouting: “Common” cranefly (Tipula oleracea) larvae occasionally can be seen at the surface feeding on foliage on warm, humid nights. Check for larval activity by taking soil samples (cup cutter plugs), dislodging the soil and looking for the dark-colored larvae. In late summer look for pupal skins that jut out from the surface. Also watch for adults flying just above the turf surface or landing on walls of buildings.

Treatment: Normally the larvae survive best in areas that have high soil moisture during the fall and spring. Withholding irrigation during the time when females are laying eggs may reduce larval survival. There are two approaches for controlling cranefly larvae. Preventive applications are made when larvae are first and second instars (usually mid September to mid October), while curative applications are made when larvae are third and fourth instars (usually mid March to mid April). Water lightly to moderately (0.05 to 0.15 inch) to move product into the thatch and enhance contact with the larvae. A second generation occurs with egg laying in April or May and larvae feeding from mid May through late August.

Scouting: Scout for turfgrass ants by watching for new mounds on the surface.

Treatment: Turfgrass ants produce mounds on turf that are unsightly and can dull mower blades. The traditional approach has been to apply a pyrethroid or chlorpyrifos to the new mounds as soon as they appear (typically late April or early May). These surface applications kill many of the workers and weaken the colony but the only way to eliminate a colony is to kill the queen. The most effective way to eliminate the queen is to use a bait formulation, which workers will carry to the brood chamber. Baits should not be watered in, while surface applications can be watered in lightly (less than 0.10 inch).