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HAIRY CHINCH BUGS IN LAWNS
Reprinted from Agriculture and Food Fact sheet, AGDEX 626. M.K. Sears.
In recent years, concern over chinch bugs causing damage to lawns has increased. Many lawns are only partially damaged, but in severe cases the entire lawn will be damaged to such an extent that it must be entirely renovated.
DAMAGE:
Chinch bugs have piercing mouthparts through which they suck the sap from the crown and stems of turfgrasses. Populations of chinch bugs tend to be aggregated which initially results in localized dead patches. These dead areas have the characteristic appearance of being brown, irregular sunken patches, which coalesce into larger dead areas as the season progresses. Weeds invade these dead areas, providing a very untidy appearance. All common turfgrasses in Ontario seen to be equally preferred by chinch bugs, but some varieties may be more susceptible to chinch bug injury.
There are several species of chinch bug, but the one causing damage to turfgrass in Ontario is the hairy chinch bug, Blissus leucopteris hirtus. This insect is quite small, the adults being 4mm in length. The immature nymphs are bright red in color when first hatched, and begin to darken from brick red to grey when they are nearly mature. They have a characteristic white band across their abdomen which becomes covered by their enlarging wing buds as they become larger.
If lawns are suspected of having chinch bug infestations, this can be accurately determined using the following method. Obtain a large can which has a circular area of approximately 200 square centimetres. Cut out the bottom to form a cylinder and force this into the turf. By filling the cylinder with water, the cinch bugs will soon float to the surface where they can be more easily seen. On a lawn which has little or no damage, ten of these samples should be taken trough-out the entire lawn. If any chinch bugs are found, treatment is advised. On lawns where damage is visible, samples should be taken in the healthy grass near the dead patches.
LIFE HISTORY:
The adult chinch bug spends the winter congregated under trees and shrubs and on the edges of lawns under hedges and in flower beds. As the temperatures become warmer in the spring, the adults move into the lawn and begin depositing eggs. As many as 20 eggs per female may be laid during May and June. The first young nymphs can be found in late May and these individuals become adults by mid-July in the Guelph area. In most of Ontario severe damage is not noticed until August after the occurrence of several weeks of hot, dry weather. Light damage does not usually appear until the middle of July. In lawns having no visible damage, the optimum time to check and treat for chinch bug infestations is the second to third week of July. This will vary from year to year and from one locality to another. At this time all eggs have hatched and the initial stages of damage are minimal. Treating an infestation at this time will remove the additional stress of chinch bug feeding during the normally dry period of August.
CONTROL:
Three insecticides are registered for control of the hairy chinch bug: carbaryl (Sevin), diazinon and chlorpyrifos. Because chinch bugs tend to avoid light at the lawn surface and will crawl into crevices in the soil below, good penetration of the insecticide is essential. Treatment should follow rainfall if possible, of if this does not occur use a lawn sprinkler for an hour preceding application. Always follow the directions on the labels exactly to ensure best results.
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Last updated:
Sept 23, 2002