Three species of chinch bug commonly invade turf grass in North America. Only hairy chinch bug (Blissus leucopterus hirtus) occurs in Canada. It is found from Ontario eastward. ^[C1]

The chinch bug is a true bug, meaning it is a member of the order Hemiptera, Bugs are characterized by 'half wings', piercing-sucking mouth parts and a 3 stage life cycle (eggs- nymphs-adults). Most bugs, including chinch, suck plant juices, but some suck blood of other insects. The big eye bug (Geocaris bullatus) is an important predator of chinch bug.

Adult chinch bugs overwinter in protected places in and around turfgrass. When temperature reaches 7^oC in spring, they come out of hibernation and mate. Egg-laying begins about 2 weeks later. Eggs are laid in leaf sheaths and on roots of host grasses. A single female can lay up to 20 eggs per day for 3 weeks or longer. ^{[C1, C2]} Time to hatching varies between about one month in early spring, and one week in summer.^[C3] In one study, the peak populations of eggs (196 per 0.1 m² — about 1 x 1 foot or 30 x 30 cm) occurred when white clover was in early bloom; in our regions that is usually in mid-June. ^[C1]

When the eggs hatch, a nymph is released. Nymphs are incompletely formed individuals that start feeding immediately. Nymphs go through a series of five development stages or 'instars' each one larger than the previous one and more similar to the adult. The exoskeleton is shed at the completion of each instar, a process called molting. Successive nymphs are progressively more mobile but do not fly.

It takes about 4-6 weeks to reach the adult stage, the shorter periods occurring when temperatures are above average. In our region, adults begin to appear in early to mid-August. ^[C4] Second-generation nymphs may be produced and do some further damage, but do they do not reach the adult stage.

There are two types of adults: short-winged flightless types and long winged types which are capable of flight. The proportions vary between populations. In southern chinch bug, the proportion of long wing forms increases with density of populations, a response which enables them to 'find greener pastures'. ^[C5] It likely happens in our species also.

In late summer and fall, adults seek hibernation sites, including damaged turf with sufficient grass to supply some shelter and food, tall grass, plant debris, under shingles and space around foundations. ^[C1]

The adult chinch bug is only 3-4 mm long. The elongate eggs are less than 1 mm long. They are white at first but become, then turn yellow and finally bright orange just before hatching ^[C1]

Stages of the hairy chinch bug (excluding the 4th instar nymph). The numbers in red are approximate lengths in millimeters; the vertical red bars indicate their relative lengths. (They are not all drawn to the same scale). Adapted from Fig 29 in Sanderson.[P1] Click on the image for a larger version. Chinch bugs observed in HRM lawns Roman numerals refer to the nymph stage. Photo at left shows young nymphs beside a finger tip. Although tiny, eggs and young nymphs stand out because of their bright red coloration. Click on the image for a larger version.

The first nymphs are about 1 mm and are bright red, with a white band across their middle. The red changes to orange, orange brown, and black as the nymphs progress through the 5 instars. ^[C1]

Adults are black with shiny white wings. There is a distinctive black spot near the margin of each forewing, and a black line extending diagonally toward the head (see Figure). ^[C1] Decker remarks: "On casual observation the adults appears to carry a white cross on its back" . ^[L1]

Expanding patches of yellowing, then dead grass in July and August
Chinch bugs feed by inserting needle-like mouth parts into crowns and stems of grasses and sucking out plant juices. At the same time, they inject a toxic saliva into the plants which disrupts the water-conduction system, causing the plant to wilt and die.

Olkowski ^[C12] describes damage by chinch bug as follows:

Most damage is caused by nymphs that concentrate in limited areas together with the adults and feed on the same plants until all the available juice has been extracted from the grass. This feeding pattern results in circular patches of damaged grass that turn yellow and then brown as they die. In the yellow stage the grass superficially resembles grass that is drought stressed. As it dies the chinch bugs work outward from the center of infestation, destroying a larger area as they advance.

Early chinch bug damage on an exposed slope. Numerous chinch bug nymphs were found at the junction between dying and living grass, confirming that this damage was caused by chinch bug.

Affected areas appear initially as scattered patches, with a severe infestation they can coalesce into larger patches. In an Ontario document ^[L2] first damage is described as "small fist sized sunken areas"; also the dead grass does not pull up easily, which distinguishes it from certain other types of damage. When chinch bugs reach high concentrations, there is a characteristic odor emitted when you walk on the grass.

Confirm that the damage is due to chinch bug, not drought or other causes
Obvious damage usually coincides with periods of hot dry weather in July and August and occurs first in the most drought stressed regions of the lawn such as on slopes and at edges. This damage can be confused with drought stress or sunscald [or a number of other problems, e.g., summer dormancy, other pests or diseases, dog urine patches, spilled mower gas. Conversely, mid-summer semi-dormancy in unwatered grass can mask the symptoms. Chinch bug damage can be confirmed by direct observation of large numbers of chinch bugs (see Section III MONITORING), and by continued extension of patches in spite of watering or late summer rains. See Other Pests and Diseases for guides to other common lawn pests and diseases^[C1]

• General Turf Insects (http://www.entm.purdue.edu/Entomology/research/cs/notes295N1/Lecture_links/Lecture24_Turf2_files/frame.htm")The Ohio State University, Spons.; D.J. Shetlar, Auth. (Viewed 16 May 2007)
  View slide nos. 18 Chinch Bugs, 19 Damage to Lawn, 20 Bugs in Thatch, 22 Life Stages, 23 Predaceous vs Pest Bug.