Chinch bugs feed on the sap of turf grasses and certain grain crops. There are two species of chinch bugs in the U.S. which have been identified as pests.
- Hairy Chinch Bugs: prefer northern turfgrasses such as Kentucky bluegrass, perennial ryegrass, bentgrass, and fescues.
- Common Chinch Bugs: prefer grain crops like sorghum, corn, and wheat but will also target the turfgrasses preferred by its cousin, the Hairy Chinch Bug.
Found throughout North America, especially in the eastern regions.
Chinch bugs are black with a white spot on their back between their wing pads. Adult chinch bugs have white wings folded over their backs and are 4 mm (1/6th of an inch) in length. Immature nymphs are slightly smaller and are bright red with a white stripe across the back. Older nymphs change to orange-brown and then to black. Nymphs are wingless. Both adults and nymphs exude a strong odor, particularly when they congregate in large numbers. Adult chinch bugs can fly but, for the most part, walk from lawn to lawn – they appear to be able to cover around 400 feet in an hour.
Adult chinch bugs overwinter in dry grasses and sod. In spring or early summer, the insects mate, and females begin to lay eggs on the leaves, stems, and roots of grasses. Eggs hatch in 1 to 3 weeks, and nymphs chew on roots until molting to adults in early to midsummer. One female can lay as many as 500 eggs. There are usually two generations per year, three in southern areas. Most damage is wrecked during hot, dry weather from June through September.
Damage and Detection
- Adults and nymphs suck sap from the roots and stems of lawn grasses, corn, and cereal grain crops. While feeding, they also poison their host with toxins that prevent the grass from absorbing water. During the winter, chinch bugs lay low in protected areas, like hedgerows and along roads and driveways; they emerge in late spring to feed and breed.
- Chinch bugs thrive in arid, hot, and sunny environments, and they cause the most damage during the hottest and driest months of the year. They congregate in open, sunny parts of the lawn and along sidewalks or driveways. Infested grass turns yellow, and patches may die off. Large infestations can devastate a grain crop or lawn.
- If care is taken to regularly feed and water a lawn or crop, and signs of drought damage persist, there may indeed be a chinch bug infestation. Turf should usually respond to watering if it is simply dry – it will not if it’s subject to a chinch bug infestation.
- Telltale signs include yellow spots of grass next to driveways, sidewalks, or the foundation of a home – areas that are naturally warmer and draw the heat-seeking chinch. Particularly in hot, dry weather, small yellow patches can gradually turn brown, and eventually, the grass dies. Weeds will begin filling in the dead areas.
- Given the chinch bugs congregate in large numbers, the determination of infection is not difficult. They also smell bad, especially when crushed or stepped on.
- To inspect for a suspected chinch bug infestation, part or spread the grass adjacent to a dead or dying patch and check the soil surface for red nymphs or black adult chinch bugs. These bugs avoid the light and may hide in soil crevices.
There is an easy trick to confirm an infestation:
1. Cut both sides off of a tin can or coffee can
2. Push the can down about two inches (5 cm) into the ground in a spot where the yellow-brown grass meets green grass
3. Pour soapy water into the can so that the water is above the grass level
4. Wait ten minutes – chinch bugs will begin to float to the surface of the water in the event of an infestation.
5. Try this in several areas, including lawn edges. If there are five to 10 chinch bugs per can, the infestation is serious enough to damage turf. Healthy turf should tolerate a level of two or three bugs per can. Turf that is in poor condition or impacted by hot, dry weather may, however, not tolerate even a low-level infestation.
Prevention and Control
Properly maintaining your lawn through regular maintenance and proper healthcare is the best strategy to protect against chinch bugs. Vigorous and actively growing lawns can better withstand weeds and lawn insects than weak or slow-growing ones.
Recommended steps for a healthy lawn include the following:
- Don’t remove more than one-third of the grass blade when mowing; cutting more weakens the lawn making it more vulnerable to subsequent infestations
- Keep thatch layer to a minimum. Thatch is the layer of dead grass between the green tops of the grass and the soil below and provides chinch bugs a nice hiding place. Remove excess thatch from your lawn with a special dethatching rake or by hiring a professional lawn care service.
- Avoid using fertilizers excessively. Overfertilization with nitrogen can lead to more chinch bugs, so use small amounts during the summer or use a slow-release formula.
- Aerate the soil.
- Don’t overwater or underwater. Chinch bug infestations can result from either too little or too much water. Chinch bugs favor hot, dry conditions, so lawns under drought conditions are more vulnerable to damage by chinch bugs. Conversely, excessive watering results in saturated, oxygen-depleted soils that can negatively impact the microorganisms required for thatch decomposition. By watering adequately, both situations are managed.
- Encourage native predators— Natural predators and parasites serve to keep chinch bug numbers under control: big-eyed bugs, pirate bugs, lacewings, the tiny wasp, lady beetles, and birds.
- Chinch bugs avoid shade, so well-placed shade plants can help keep the sun-loving chinch bug away from certain areas.
- If an infestation has taken root, the homeowner may consider it necessary to use insecticides. Some insecticides can help prevent and control chinch bug populations, but they are usually more successful if applied early. Treatments are available in granular and liquid forms. As chinch bugs reproduce rapidly and can develop resistance to any particular treatment, it is advisable to rotate the type of insecticide used. Additionally, pesticides will kill chinch bugs but not their eggs, so several applications may be necessary.
While every effort has been made to describe these plants accurately, please keep in mind that height, bloom time, and color may differ in various climates. The description of these plants has been written based on numerous outside resources.