Insects & Other Pests ›
The southern chinch bug is common throughout the Gulf states and into Georgia and North Carolina. It is primarily a problem on thick mats of turf in sunny, open areas. It is most commonly reported as a pest on St. Augustinegrass, but also infests centipedegrass, zoysiagrass, bahiagrass, torpedograss, pangolagrass, and occasionally Bermudagrass.
The southern chinch bug adults are oblong, oval, and black with shiny white wings. They are 1/6-1/5 inch long. Each wing bears 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.
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 which attack chinch bugs and keep populations low. Proper irrigation can help reduce the likelihood of chinch bug damage.
The first step is to be certain that 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 20-25 chinch bugs per square foot. (See also, "plastic bag method" below.) 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. Recommendations for insecticides approved for control of these insects in home lawns can be found under Chinch Bugs in INSECT CONTROL IN HOME LAWNS in the NC Agricultural Chemicals Manual.