The scarab beetle family includes many beetle species known as destructive turf and garden pests. This includes devastating invasive pests, such as European chafers and Japanese beetles, as well as dozens of species known regionally as May beetles and June beetles. In their adult stage, some scarab beetles damage plant leaves, flowers and fruits. In their immature larval stage, known as white grubs, scarab beetles damage roots of turf grasses and other plants, from edible berries and fruits to evergreens and ornamental trees. Where grubs are numerous, root-damaged plants may die.
Scarab Beetle Identification: Scarab beetles vary significantly depending on the species. May and June beetles are relatively large, heavy-bodied beetles that grow up to 1 inch long — about twice the size of Japanese beetles. They vary in color from red-brown to near black, with several species displaying metallic green or bronze. Common May and June beetle larvae are creamy white, brown-headed grubs that measure up to 1 1/2 inches long. Like other white grubs, the six-legged larvae curl into "C" shapes when disturbed.
Signs/Damage of Scarab Beetles: Depending on the species, adult scarab beetles emerge from the soil to mate and lay eggs any time from late spring into summer. Drawn to light, the larger species are awkward nighttime fliers that attract attention as they repeatedly crash into windows and screens. Those that feed on plants above ground may skeletonize leaves, eat flowers and chew holes in fruit.
Scarab grubs typically hatch in early summer and feed on grass and plant roots just below the soil line. Affected plants show drought-like symptoms, including stunted growth, wilting, yellowing and browning. Turf damage often shows up the following spring when dead and dying grass fails to turn green. With heavy infestations, the soft, spongy turf can be lifted and rolled like a rug, revealing feeding grubs and damaged roots.
How to Control Scarab Beetles: Effective scarab beetle control targets both the grub stage and adult beetles. Treat any areas where you see beetles or know past problems occurred. The optimal time for grub treatment is late summer and early fall when grubs are still young, small and close to the surface. Treat adult beetles any time they appear.
GardenTech® brand offers a highly effective granular product that works above and below the soil line to kill grubs and adult scarab beetles by contact. This product continues protecting for up to three months:
- Sevin® Insect Killer Granules treat lawns, fruit and vegetable gardens, ornamental gardens and areas around your home. For best results in lawns, mow your grass at 3 inches or shorter and apply the ready-to-use granules with a normal lawn spreader. Water the treated area immediately with 1/2 inch of water to release active ingredients down into the soil.
For added protection, treat adult beetles as they emerge to feed and lay their grub-producing eggs. The following non-staining liquid products treat lawns, edible and ornamental gardens, and your home's foundation up to a maximum height of 3 feet. These products kill scarab beetles by contact and keep protecting for up to three months:
- Sevin® Insect Killer Ready to Spray attaches to a normal garden hose to measure and mix automatically as you spray. Treat at the earliest sign of newly emerged beetles or anywhere they're expected. Spray to cover all lawn and plant surfaces thoroughly.
- Sevin® Insect Killer Concentrate, used with a regular pump-style sprayer, simplifies extensive coverage of small trees, shrubs and lawns. The convenient measuring cap makes it easy to get just the right amount of concentrate. Add water, mix well, and spray all surfaces thoroughly.
Tip: To confirm grub activity in an area, use a spade to lift a square foot of suspected turf or garden soil about 2 to 3 inches deep. If you find 10 or more grubs per square foot, prompt, thorough treatment is critical.
Always read product labels and follow the instructions carefully, including pre-harvest guidelines for edible crops.
GardenTech is a registered trademark of Gulfstream Home and Garden, Inc.
Sevin is a registered trademark of Tessenderlo Kerley, Inc.