One of the most common and potentially destructive insect in lawns of all types is white grub. It is also known as grub worms, annual white grubs or just plain old grubs. They damage turf by feeding on the roots of the plant as well as disturbing the soil with their constant search for edible roots. They eat whatever is in front of them, including soil and other organic matter.
The digging and feeding of grubs is bad enough, but there are several animals that will feed on grubs when the grubs are active. Grubs are generally active in the late summer through fall and then again for a brief time in the early spring.
Birds, skunks, raccoons, armadillos, foxes, wild pigs and moles may dig up a lawn while looking for a tasty grub meal. These varmints can do more damage to a lawn with their digging then the damage caused by the grubs themselves.
Grubs are members of the scarab beetle family. Some of these stout-bodied insects can be colorful in design.
Fun fact, the ancient Egyptians fashioned jewelry that depicted the shape of the scarab beetle. The scarab beetle that was common in ancient Egypt is the dung beetle. It had a habit of rolling balls of dung and deposited the balls in their burrows, on to which they would lay their eggs. When the eggs hatched, the larvae would feed on the ball of dung. After the ball was consumed, the young adults would emerge from the burrow, looking for more food or a mate. This emergence was seen as a type of creation and it was associated with one of their gods.
In North America, there are at least 10 species of white grubs, 6 of which are native to the area. The accidentally introduced species are the European chafer, oriental beetle, Asiatic garden beetle and the Japanese beetle.
The Japanese beetle has become a severe pest mainly east of the Mississippi River, although their range seems to increase in size every year. Most grubs have a one year life cycle, but there are ones that have a two or three-year life cycle. Their life cycle is known as metamorphosis.
Grub Life Cycle
1. Begin life as an egg, laid into the soil 1 to 4 inches deep in a dehydrated state
2. Eggs absorb water from the surrounding soil to remain viable
3. After 2 to 3 weeks, eggs hatch into tiny grubs, about the size of a bluegrass seed
4. Start feeding on fine root hairs and other organic matter
5. Continue feeding until October/November, then move deeper into soil as temperatures fall
6. Resurface in early spring, do a little bit of light feeding and then dig back into the soil to pupate
7. After a few more weeks, adult beetles emerge to lay eggs and the whole life cycle begins again
The time to apply grub control for this year is from late June through mid-August. Most of the grub control products available work best as a preventative, keeping the newly hatched grub from growing. If you plan to apply the product yourself, be sure to read and follow label rates and directions. Since the grubs live and feed in the soil, it is important that the product is thoroughly watered into the lawn to reach the grubs.
If you or your neighbors had grubs in the past, contact your local lawn care professional at Spring-Green. They will be happy to provide this valuable service to help prevent grub damage to your lawn.