Insect alert: Fall armyworms are present in turfgrass

Watch for the following problems. The hotline volunteers have received several requests on the following:

Fall armyworms in turfgrass

Fall armyworms have been present in turfgrass for the past week or so and it appears they are now in full gear.

There are a variety of sizes present and larger armyworms are most damaging. They typically begin near the edge of a turf area and invade across the turf leaving serious damage behind.

This edge effect is because the moths typically lay eggs on fences, shrubs, signs, buildings, etc. and the larvae must move into the turf.

The easiest way to detect armyworms (larger armyworms may hide during the day to escape birds) is to drench the area with a 2 percent soapy water solution. The armyworms will immediately wiggle to the surface and become easy to see.

The presence of many birds in a turf area may also be an indicator fall armyworms are present.

Treatments are usually most effective if applied late in the day and if the area is not mowed for several days. If a spray is used, hold off on irrigation for at least 24 hours.

Newly sprigged and sod areas are at greatest risk for serious damage from this pest. Several treatments are available. Contact the Cooperative Extension Service.

Chinch bugs

Southern chinch bug adults are oblong, oval and black with shiny white wings. They are about 3/16-inch long. Each wing has a distinctive triangular black mark.

First and second instars are bright orange. Third and fourth instars are darker red and the last instar resembles the adult.

Do not confuse the adult with big-eyed bugs; they are a problem primarily on St. Augustinegrass, but also may infest all other warm season grasses.

Chinch bug populations are concentrated near the surface of the soil. Nymphs extract plant juices with needle-like mouthparts and are primarily responsible for lawn damage.

On St. Augustinegrass, feeding is primarily restricted to the tender basal area of grass blades and nodes of runners. As the nymphs feed, yellowish spots first appear and soon become brown, irregular dead areas in the grass.

As the grass dies, nymphs move to the periphery of the dead spots causing the area to expand. Chinch bug damage is greatest during the summer when hot, dry conditions exist.

Except for southern Florida where chinch bugs are active year around, southern chinch bugs over-winter as eggs. The eggs are found inserted in crevices at grass nodes or between overlapping leaf blades.

Females deposit 100 to 300 eggs. Eggs hatch in the spring, releasing nymphs to feed and develop for two to six weeks. Adults cause little damage but new generations of nymphs increase the feeding damage.

Good cultural management can reduce the need for chemicals. Keep thatch to a minimum. Thatch provides protection for chinch bugs and chemically interferes with many insecticides. Be sure to observe proper mowing, fertilization, watering, and specific lawn care practices for St. Augustinegrass to minimize thatch (See Carolina Lawns AG-69).

The Raleigh variety of St. Augustinegrass is highly susceptible to chinch bug damage. The varieties of Floratam and Floralawn show varying degrees of resistance; however, they lack cold-hardiness. Check with your county Cooperative Extension office to see how these varieties perform in your area.

Chinch bugs are attacked by several predatory insects. Repeated use of chemicals on a lawn may also reduce the beneficial insects. Apply insecticides only when necessary.

Cool, cloudy weather promotes fungal pathogens that attack chinch bugs and keep populations low. Proper irrigation can help reduce the likelihood of chinch bug damage.

Prior to beginning chemical control, the first step is to be certain the lawn problem is due to chinch bugs. Check the lawn weekly during the growing season, especially in direct sun and along walks and driveways. Look for off-color areas.

Where chinch bugs are suspected, part the grass at the edge of the affected areas and examine the soil and base of the turf. Check in several places.

An approximate treatment threshold is 20 to 25 chinch bugs per square foot. If the problem is localized, spot treatment of off-color turf and around the perimeter of the affected spot is appropriate and preferred.

Insecticides may be used in granular or liquid formulations applied with hose-end sprayers.

Compounds containing the following chemicals are good for homeowners: Naturals-T, Baygon Pyrethroids (Bug-Br-Gone), Advanced Lawn Telstar, Tempo, Deltagua and Menace.