Chinch bugs

Identification

  • chinch bugAdults are 3-5 mm long, grayish black, with an X on their backs.
  • Young nymphs are brick red, with a white bank across the middle body.
  • They congregate in areas, are very active and scurry for shelter into the soil when the turf is examined.
  • They tend to be found in warm, open turf, in areas which are not frequently irrigated and more often on fescue than Kentucky Bluegrass.

Evidence

  • Feed by sucking juices from the grass crowns, causing grass to wilt and die.
  • Injury shows up during mid-August when grass is already under heat and drought stress, before this the chinch bugs were small and don’t have a large appetite.
  • Roots of the grass stay intact, so the grass cannot be pulled up easily.
  • Injury shows up as brown, irregular, sunken patches in August.

The best time to check for infestations of chinch bugs is mid-late July.

  • Cut out the top and bottom from a large can, then force the can into the turf.
  • Fill the can with water, any chinch bugs present will float to the top, if there are more than 20 chinch bugs, you may have a problem.

Control

  • Irrigated turf is more able to tolerate chinch bug feeding. 
  • Research has shown that perennial rye turf cultivars containing high levels of endophytic fungi show some resistance to chinch bug feeding. 
  • Thatch that is more than 12mm thick, will stimulate chinch bug: 
    • More thatch provides more habitats for chinch bugs. Nymphs stay in the thatch layer most of the time, probably because it provides protection against desiccation and predators. Adults may overwinter in thatch. 
    • Excess thatch increases water stress. Once dry, thatch does not wet easily, and acts as a barrier to movement of water into soil during short rainfalls. On the other hand, once it gets wet, it holds water and encourages shallow rooting of the grass, which then becomes much more drought susceptible in dry weather. 
  • Put 30 ml of dishwashing soap in 7 litres water and drench a small area of lawn. The chinch bugs will crawl to the surface of the grass to escape the soap. Lay a flannel sheet over the treated area and wait 10 minutes. The chinch bugs will crawl onto the sheet, where their feet will become trapped in the flannel nap. They can be vacuumed off the sheet or drowned in a bucket.