NSECT APPEARANCE: Billbug larvae—which do most of the damage—are white, legless grubs about 3/8 inch to 1/2 inch long, with snouts used for burrowing and chewing off plants.
LIFE CYCLE: Overwintering adults emerge in midspring when they often can be found crawling on sidewalks and driveways. Soon after emerging, they lay eggs on the stems of grass plants. Grubs generally emerge in May or June and then tunnel into the stems, from where they eventually will migrate into the root zone.
DAMAGE THRESHOLD: More than one grub per square foot of lawn.
CONTROL: Spray grass foliage and thatch in spring (when the adult billbugs are moving around). Use carbaryl, chlorpyrifos, diazinon, or neem.