Black Beetles in Wintergreen Grass

African black beetles damage lawns by gnawing at the grass' roots.

Wintergreen is a hardy favorite among lawn aficionados; it's tough, resilient and forgiving. But maybe it's not doing as well as it should be. If your lawn has a yellowed, scraggly appearance, try to pull up a handful of the dead blades. If they come up easily with little resistance, you've got black beetles. Another sign is if you often see birds pecking at your lawn: they're likely feeding on black beetles.

Wintergreen

Wintergreen is a favorite for its lush, even coverage.

Wintergreen is a variety of couch grass native to Australia, but it has proven popular in North American and European markets as well. It gets its name from its short period of dormancy in the winter: unlike other types of lawn turf, it doesn't die but instead begins growing again in the spring. It's not a delicate grass by any means, but can still be harmed by black beetles.

Black Beetles

Black beetles do the most damage to lawns as grubs.

The African black beetle (Heteronychus arator), or plain old black beetle, is a pest notorious for infesting lawn grass of all types, including wintergreen. These beetles are relatively large and shiny black, and are capable of flight, though you're more likely to find them in the soil. The larva, or grub, is white with a hard brown head, black jaws, and three pairs of legs. Grubs rest in a curled position, earning them the nickname "curl grubs."

Damage

The reason why black beetles are so destructive to lawns is the way they feed. When the beetle hatches and begins to feed in October, it not only eats away at the grass' roots but also repeatedly burrows to the surface and then back down again, leaving unsightly mounds and damaging the grass' ability to absorb nutrients. The grass will begin to turn yellow and die in patches where the most beetles are.

Organic Removal

Sparrows are more than happy to help you with your beetle problem.

For those of us lucky enough to live on a farm or acreage, chickens and other birds like guinea hens love to eat beetles and should be encouraged to forage on the lawn if feasible. Urbanites can encourage city birds like wrens and sparrows to visit the lawn by installing and maintaining feeders and bird baths on their premises. As long as you've avoided using pesticides on your lawn, the beetles and other insects will be safe for birds to eat.

Insecticides

As green as we'd like to be, sometimes organic removal is not enough. If you find you need something stronger, consider spray pesticides catering directly to beetles or grubs. Grub pesticide should be particularly effective in autumn, as that's when the larvae are just hatching and beginning to feed. Beetle pesticide can be used in the winter or early spring; it won't be effective in the early summer because the adult beetles naturally begin to die off then.

References

• Hick's Turf: Wintergreen Couch
• Heyne's Garden Centre: African Black Beetle
• Government of Western Australia Department of Agriculture: African Black Beetle (Heteronychus Arator)

Resources

• Canadian Gardening: Natural Lawn Care
• Cornell Lab of Ornithology: Attracting Birds