Pest Watch 24

Chinch bugs

(Blissus spp.)

Chinch bugs are the most important “true bug” pests of lawns. The southern chinch bug (Blissus insularis) is more common in the Southeast, South, and parts of the West, where it feeds primarily on St. Augustine grass as well as bermudagrass, centipede-grass, and zoysiagrass. The hairy chinch bug (B. leucopterus hirtus) is a pest of the Northeast and Upper Midwest, where it feeds on Kentucky bluegrass, perennial ryegrass, zoysiagrass, bentgrass, and fescues.

BIOLOGY: The life cycles of the hairy and southern chinch bug are similar. Adult chinch bugs overwinter in leaf litter and thatch. They are black, about one-fifth of an inch long, and have white patches on their wings. Southern chinch bugs are active during the winter months in the South, but their development is slow. Hairy chinch bugs emerge in the spring and become active when daytime temperatures reach 70T. Adult females lay eggs in leaf sheaths, thatch, and in the ground near the roots of host plants. The nymphs that hatch are typically colored red or orange.

Both adults and nymphs use their needlelike sucking mouth-parts to extract sap from crowns, stems, and stolons and may introduce a toxic saliva that blocks phloem and xylem tissue. Hairy chinch bugs produce one to two generations a year in the North. Southern chinch bugs typically produce three to four generations. Seven or more generations occur in southern Florida.

SYMPTOMS: Chinch bug feeding produces irregular patches of yellowing turf as leaf tips turn brown. As the blades wilt and wither, the patches become straw colored. Damage typically begins near pavement or other drought- and heat-stressed areas.

CONTROLS: A foolproof way of confirming the presence of chinch bugs is to cut out both ends of a coffee can and push one end two to three inches deep into the grass at the edge of a yellowing area. Fill the can with water and keep it filled for five minutes. Chinch bugs, if present, will float to the top. Where 20 or more chinch bugs per square foot are found, chemical control may be necessary. Use bifenthrin (Ortho Bug-B-Gon MAX Lawn & Garden Insect Killer Concentrate), lambda-cyhalothrin [Spectracide Triazicide Soil and Turf Insect Killer Concentrate), cyfluthrin (Bayer Advanced PowerForce Multi-Insect Killer Ready-to-Spread Granules), or imidacloprid [Bayer Advanced Complete Insect Killer For Soil & Turf Ready-To-Spray).

To prevent chinch bug infestation, use slow-release fertilizers and keep the lawn mowed to an appropriate height. Irrigation during the spring and early summer will also reduce the hot, dry conditions that chinch bugs favor.

Finally, some grasses are chinch bug resistant. Fungal endo-phyte-infected perennial ryegrasses, fine fescues, and tall fescues are resistant to hairy chinch bug. St. Augustine grass ‘FX10’ is resistant to southern chinch bug, while ‘Bitterblue’, ‘Floralawn’, ‘Floratine’, and ‘Seville’ are somewhat resistant.

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