White Grubs

The Insect
It's late summer. You begin to notice brown spots in your lawn even though you've been diligent about watering. When you kneel down to study the matter you grasp the sod and it comes up like a piece of carpet. That's when you see them, beneath that section of lawn, grubs: ¼ to 1 inch long, white C-shaped creatures with a brown head, six small legs and a semi-translucent body. They've been munching on the roots of your grass, growing fat on your lawn. Not only do they kill the grass when their population is too high but starlings, raccoons, skunks and moles wreck your lawn as they hunt and devour these grubs.

Their Lifecycle
In late June the adults of the white grub emerge as lumbering, stupid, tan beetles commonly called June Bugs. These Baby Hueys of the insect world do not feed; their only purpose is to mate, lay eggs, crash into yard lights and die like mindless Kamikazes.
The eggs are laid in moist soil in July and hatch in 2 to 3 weeks. The ravenous grubs begin feeding immediately. A few grubs here and there are no big deal. But when the grub population in non-irrigated lawns reaches 10 per square foot, and in irrigated turf 15 to 20 per square foot, severe damage can occur. And you may not even notice it until mid to late August.

In winter grubs burrow below the frost line where they hibernate until spring. Then in April the grubs wake from their stupor and begin crawling back to the root zone of your lawn where they feed sporadically until late May when pupation occurs. Don't waste time or money attempting control in the spring. They don't feed enough to justify it.

Controlling White Grubs
Beginning in early May and no later than the middle of August, apply Grubex, a season long insecticide to the entire lawn. It's available in a granular form and the earlier in the season it goes down the better. (Granular is the quickest and easiest. Simply apply it with a fertilizer spreader.) It has to be watered in with 1/3 to 1/2 inch of water to push the chemical 1 to 2 inches deep to reach the grub zone.

If grubs are present, in 10 to 18 days the grubs will be sick and quit feeding. Their slow, lingering death will take a little longer. If Grubex is applied in May, it will kill the grubs before they can become large enough to damage turf. Grubs are easy to control. Like every other aspect of turfgrass culture, it's a matter of doing the right thing at the right time.

Tip 1: Grub Attack and other milky spore products you see advertised in magazines do not work on our annual white grubs only on Japanese beetle larvae. The type of grubs milky spore is supposed to control are not a major concern in our area.

Tip 2: Do not apply Grubex to waterlogged areas. The product may not work effectively under these conditions.