Chinch bugs originally were a southern lawn pest, brought here years ago with the transportation of plant materials, and are now a major pest in southern Ontario lawns.
Chinch bugs can over-winter in shrub and flower beds, emerging as the hot warm weather arrives, usually in mid July. The adult chinch bug is a small, blackish insect with a distinctive diamond pattern on its back, usually with a whitish outline. They lay their eggs in early spring and hatching begins to occur in early summer. The nymph stage of this insect is very small, and reddish in colour with a white band of colour in the middle of their body. Both the adult and nymph stages of these insects are very hard to see or find. They are usually located in the thatch of your lawn, in the sunny hot areas and not in the shade.
Damage appears quickly in hot dry areas of your lawn, as yellowing spots both small and large. Sometimes a very large section of lawn is damaged very quickly. People who have not watered their lawns think it is just a drought but not watering, plus the chinch bug feeding, can kill grass very quickly.
One method of checking your lawn is to take a large can, cut open both ends so you have a large tube. Place the can at the edge of a dead spot, covering both a dead area and some still green grass; press the opened ended can into the ground past the thatch level. Now fill the can with water. If you have chinch bugs they will then float to the surface of the water.
Controlling chinch bugs can be done with a live product called nematodes; these microscopic insects are sprayed on your lawn and must be kept moist for several days. Nematodes work only on the nymph stage of chinch bugs before any damage occurs. If you have had a problem with chinch bugs in the past it is an excellent idea to treat your lawn with nematodes, as soon as the first hatching occurs, which is usually in June.
If you are having problems with chinch bugs after June, some success has been shown with spraying the lawns with liquid kelp. Spray only the damaged areas, as well as the immediate area around the damaged area. Keep your lawn well watered, fertilized and do not cut the lawn too short; 2 1/2 to 3 inches high is good in hot weather. Repeat treatments will most likely be required. If the damaged area needs reseeding later, use a grass seed with a perennial rye grass mixture containing endophytes (a fungus which has show some resistance to chinch bugs, as well as other insects).
Keeping your lawn healthy, well watered, fertilized and growing, is your best protection against chinch bugs, weeds, crabgrass and grubs.