Pest Identification: Grubs
Most Common Types
Grubs are often called lawn grubs or grub worms. They are the immature, larval form of beetles such as the scarab beetle, the masked chafer, the June bug, and the Japanese beetle.
What They Look Like
Grubs are milky white with a brownish head. They curl their fat, soft bodies into a “C” shape when disturbed and have legs located near the head.
Where They Live
Grubs live in the soil and eat plant roots including roots of lawn grass.
Where They Nest
In midsummer, female beetles spend several weeks laying eggs in the soil. They hatch about two weeks later, producing grubs which feed on grass roots close to the surface. The grubs feed for several months, growing larger while consuming more roots. Turf damage begins to appear in the fall. As temperatures drop, grubs dig down below the frost line to overwinter. The following June, they mature and emerge as beetles.
Steps to Prevent
Check for brown patches in an otherwise green lawn. If the turf lifts easily, it means the grass has no roots and grubs may be the culprit. Another sign of grubs is the presence of birds, skunks, or raccoons tearing up the turf trying to uncover a grub dinner. If grubs have been identified, spread preventative pesticides which are contained in a nitrogen fertilizer. Always follow the pesticide directions; if applicable water afterwards to move the pesticide down through the soil.
Are They Harmful?
Grubs only kill lawns when they are present in large numbers. A healthy, green lawn can contain up to 9 grubs per square foot. Ten or more grubs will create visible damage to the lawn, requiring treatment.