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Chinch Bugs

Rick L. Brandenburg & S. Bambara, Extension Entomologists

CAUTION This information was developed for North Carolina and may not apply to other areas.


[General Information] [Biology] [Control] [Other Resources]
Chinch Bugs, Southern Chinch Bug, Blissus insularis Barber, (HEMIPTERA: Lygaeidae: Blinninae)

General Information

chinch bug adult 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.

Biology

big eyed bug adultChinch 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, the 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 overwinter as eggs. The eggs are found inserted in crevices at grass nodes or between overlapping leaf blades. Females deposit 100-300 eggs. Eggs hatch in spring which release nymphs to feed and develop for 2-6 weeks. Adults cause little damage, but new generations of nymphs increase the feeding damage.

Control

Cultural-

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.

Chemical-

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.

Management for Professionals

The approximate threshold at which damage is first noticed is 20-25 chinch bugs per square foot. Visual examination and the "plastic bag method" may be used for detection. For the "plastic bag method", place a large square of turf in a large sealable, clear plastic bag. Seal it and place it in the sun. After a several minutes and as the bag heats, insects will leave the turf and collect on the inside of the bag where they can be counted. Sample several (non dead) areas, especially around the edge of an affected region. The "flotation method" may be also be used. For the flotation method, force one end of a six-inch diameter coffee can with both ends removed, into to the turf. Fill the can with water for ten minutes.  Examine the insects floating on the water surface.  Treatment threshold is 4-5 chinch bugs per can. Be sure not to confuse adults with big-eyed bugs.

Recommendations for insecticides approved for use on sod farms, golf courses or other commercial sites can be found in COMMERCIAL TURF INSECT CONTROL in the NC Agricultural Chemicals Manual.

Consult the product label for other important information on application and restrictions. Resistance to some chemicals has been reported. Rotate chemicals to avoid problems. Use of surfactants may be helpful.

To make turf less attractive to chinch bugs in regularly infested areas, use organic, slow-release, nitrogen sources and reduce the rate of applied nitrogen.

For additional information on insect control and pesticide use Contact your county Cooperative Extension Center .

Additional Reading:

Useful Links:


Because environmental conditions, methods of application by growers, and performance of the chemicals may vary widely, control results may also vary.

Recommendations for the use of chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by the North Carolina Cooperative Extension Service nor discrimination against similar products or services not mentioned. Individuals who use chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage and examine a current product label before applying any chemical.

Other Resources


Published by North Carolina Cooperative Extension Service

Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University at Raleigh, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.

Rick L. Brandenburg, James R. Baker & S. Bambara, Extension Entomologists

ENT/ort-112 December 1998 (Last revised April 2002)

Web page last reviewed Januaryt, 2011 by webperson.