On this page
How to identify it
- Adults are black and about 1/10 inch long, and females are a little larger than males.[1]
- Adults come in two forms. Some have full wings that reach the tip of the abdomen and can fly to new turf; the rest look wingless but have very short wing stubs. Up to half of the first summer generation is fully winged, while the fall generation is mostly short-winged.[1]
- Newly hatched nymphs are only about 1/64 inch long, bright red with a white band across the abdomen. They turn orange-brown and then black as they grow.[1]
Look-alikes
| Look-alike | How to tell them apart |
|---|---|
| Hairy chinch bug | A close relative that is the usual chinch bug in northern cool-season lawns. Fine fescues that are moderately to highly susceptible to the hairy chinch bug were moderately to highly resistant to the western chinch bug in greenhouse tests.[4] |
| Southern chinch bug | The St. Augustinegrass pest. St. Augustinegrass varieties that the southern chinch bug damages, such as Raleigh, were highly resistant to the western chinch bug, and western chinch bugs did not reproduce on St. Augustinegrass in no-choice tests.[4][3] |
Where it lives
Its reported range includes California, Colorado, Kansas, Montana, Nebraska and New Mexico, plus Alberta, British Columbia, Manitoba and Saskatchewan in Canada. In Nebraska it has been found with buffalograss across the state and in surrounding areas since it was first detected in a Lincoln lawn in 1989. Utah State Extension lists it among the chinch bugs that may feed on turf in Utah.[2][1][7]
Biology and life cycle
Western chinch bugs spend the winter as short-winged adults in and around the lawn. In early spring they come out, mate and lay eggs in the plant crowns or the soil underneath. In Nebraska the eggs hatch in mid to late May.[1]
First-generation adults appear in late June or early July. Their eggs hatch from mid to late July, and these second-generation nymphs finish developing in September and early October before overwintering as adults.[1]
They feed on many grasses, including Kentucky bluegrass, perennial ryegrass, wheat, barley, rye, sorghum and green and yellow foxtail, but buffalograss and zoysiagrass are the clear favorites and the most likely to become infested.[1][3]
In choice tests the bugs gathered mostly on warm-season turfgrasses: buffalograss, zoysiagrass, bermudagrass and St. Augustinegrass. In no-choice tests they reproduced on 15 of 18 grasses but not on bermudagrass or St. Augustinegrass, and they killed buffalograss plants before offspring could be produced.[2][3]
They do best in turf with a lot of thatch and organic debris.[1]
In Utah, chinch bugs feed on turf especially during severe heat and drought.[7]
Damage and signs
- Chinch bugs suck sap from the crown area of the grass and may inject a salivary toxin that damages tissue and blocks the movement of water and nutrients.[1]
- Leaves first turn reddish purple. In the lawn, damage shows as patches that turn yellow and dry to straw brown. Heavy infestations can badly thin or kill the stand.[1]
- In greenhouse tests western chinch bugs did not cause much damage to any turfgrass or sorghum variety other than buffalograss.[4]
- Field crops and grassy weeds next to buffalograss or zoysiagrass can harbor the bugs, and they can be damaged too once the main host is heavily hit.[1]
Health risk
Nebraska Extension and the published studies describe it only as a pest of grasses and do not list any health risk to people.[1][2]
Control
Prevention
Keep the lawn healthy and limit thatch through mowing and cultural care. The bugs favor heavy thatch, so less thatch can discourage new infestations and help reduce existing ones.[1]
Plant resistant buffalograss. In Nebraska research the seeded cultivars Cody and Tatanka and the vegetatively propagated Prestige were moderately to highly resistant, though heavy infestations can still damage them.[1]
Treatment is likely needed only when counts top about 20 to 25 per square foot (five coffee cans equal one square foot) and feeding damage is visible. Check areas where buffalograss or zoysiagrass borders crops or grassy weeds.[1]
Traps and physical control
To check for bugs, cut out a small section of turf and shake it hard over white paper. Or remove both ends of a 2-pound coffee can, press it firmly into the soil where you suspect bugs and fill it with water; chinch bugs float to the top where you can count them.[1]
Biological control
Studies in Nebraska buffalograss found many natural enemies in the turf, including spiders, predatory ants, ground beetles, rove beetles, bigeyed bugs and parasitic wasps.[5]
Pesticides
In Nebraska trials bifenthrin, lambda-cyhalothrin and carbaryl gave acceptable control. Mow to 1 1/2 to 2 inches and remove clippings first, then water in liquid sprays with 1/8 inch of water and granules with at least 1/4 inch. Very heavy infestations may need a second application, typically mid-June and late July. Follow the label.[1]
Neonicotinoid insecticides are generally not recommended for chinch bugs because results are inconsistent.[6]
Common questions
- Why is my buffalograss lawn turning straw brown in patches?
- Western chinch bugs are a likely cause in buffalograss. Feeding first turns leaves reddish purple, then patches yellow and dry to straw brown. A coffee-can float test or shaking a piece of turf over white paper will show whether the bugs are there.[1]
- Which buffalograss resists western chinch bugs?
- Nebraska research rated Cody, Tatanka and Prestige moderately to highly resistant. Heavy infestations can still damage them.[1]
- Will western chinch bugs damage my bluegrass or fescue?
- They can feed on Kentucky bluegrass and perennial ryegrass, but buffalograss and zoysiagrass are their preferred hosts. In greenhouse tests they did little damage to turfgrasses other than buffalograss, and fine fescues were moderately to highly resistant.[1][4]
Sources
- University of Nebraska-Lincoln Extension, “Chinch Bugs in Buffalograss and Zoysiagrass Turf (G1952).” extensionpubs.unl.edu/publication/g1952/na/html/view (accessed 2026-11-10)
- Journal of Insect Science, “Eickhoff, Baxendale and Heng-Moss (University of Nebraska-Lincoln). Host preference of the chinch bug, Blissus occiduus. Journal of Insect Science 6 (2006) 1-6, PMID 19537992, PMC2990293.” pmc.ncbi.nlm.nih.gov/articles/PMC2990293/ (accessed 2026-11-10)
- Journal of Economic Entomology (Entomological Society of America), “Eickhoff, Baxendale, Heng-Moss and Blankenship. Turfgrass, crop, and weed hosts of Blissus occiduus (Hemiptera: Lygaeidae). Journal of Economic Entomology 97 (2004) 67-73, PMID 14998128.” pubmed.ncbi.nlm.nih.gov/14998128/ (accessed 2026-11-10)
- Journal of Economic Entomology (Entomological Society of America), “Anderson, Heng-Moss and Baxendale. Evaluation of cool- and warm-season grasses for resistance to multiple chinch bug (Hemiptera: Blissidae) species. Journal of Economic Entomology 99 (2006) 203-211, PMID 16573341.” pubmed.ncbi.nlm.nih.gov/16573341/ (accessed 2026-11-10)
- Journal of Economic Entomology (Entomological Society of America), “Carstens, Heng-Moss, Baxendale, Gaussoin, Frank and Young. Influence of buffalograss management practices on western chinch bug and its beneficial arthropods. Journal of Economic Entomology 100 (2007) 136-147, PMID 17370821.” pubmed.ncbi.nlm.nih.gov/17370821/ (accessed 2026-11-10)
- Journal of Economic Entomology (Entomological Society of America), “Stamm, Baxendale, Heng-Moss, Siegfried, Blankenship and Gaussoin. Dose-response relationships of clothianidin, imidacloprid, and thiamethoxam to Blissus occiduus (Hemiptera: Blissidae). Journal of Economic Entomology 104 (2011) 205-210, PMID 21404859.” pubmed.ncbi.nlm.nih.gov/21404859/ (accessed 2026-11-10)
- Utah State University Extension, “Sod Webworms.” extension.usu.edu/planthealth/research/sod-webworm (accessed 2026-11-10)
- iNaturalist, “Blissus occiduus taxon page (order and family).” www.inaturalist.org/taxa/261573 (accessed 2026-11-10)