May Beetles and June Beetles
• Adult beetles are oval, 3/4 – 1 inch long, and brown and black. The first pair of wings are hard and and shell-like; the second pair of thin and membranous wings are hidden beneath the first pair.
• Beetle larvae, commonly referred to as white grubs, are worm-like C-shaped, and, at maturity, up to 2/3 to 1-inch long. The tip if their abdomen (raster) has two distinctive parallel rows of hairs.
Biology and Habits:
• Females burrow 1 to 4 inches into the soil where they lay their eggs singly or in small clusters.
• Eggs hatch within 2 to 4 weeks; the grubs continue to develop over the next 2 to 4 years.
• At maturity and during the fall of the year, the grubs pupate for approximately 30 days, develop into adults, burrow down in the soil, and emerge as adults in the spring.
• The life cycle typically requires three years.
• Each year, from spring to fall, the larvae feed on grass roots. As cooler weather approaches, the developing grubs burrow down as far as three feet deep and remain there throughout the winter. In the spring, the larvae move closer to the soil surface and resume feeding. This cycle is repeated until development is complete.
• Adult beetles feed at night in nearby trees, cause little damage, and return to the soil during the day.
• Bluegrass, St. Augustine, Bermuda and fescues.
• White grubs feed on grass roots cutting them completely off just below the soil line.
• May and June beetles grubs feed on organic matter and break off roots below the soil line as they make horizontal tunnels.
• The grass dies in irregular brown, spongy patches which can easily be rolled back like a carpet.
• Collateral turf damage can be caused by animals, i.e., skunks, opossums, birds, and racoons which dig in the ground for grubs.