Winterthur Garden Blog

by Frank Quinnette

On my way to work this morning I heard a radio commercial for grub control. It’s a tongue-in-cheek spot from a major lawn care product supplier that is pretty funny really. Kind of 1950’s, flying-saucer-ominous-voice-in-panic type deal. Ugly monsters in the lawn devouring grass roots! Run for your lives! Something like that. Smart advertising for the most part. It blends the seriousness of a grub problem on turf with a “…don’t worry, it can be controlled. Even prevented…” message. For guys like me who worry about turf all year long and the blade-watching, home turf hobbyists across the country, this is good news. So I figured this was a good subject to blog about.

Grub damage at Winterthur

No doubt; white grubs can be a nightmare. We’ve had problems here at Winterthur in the past. They cause turf damage quick, fast, and in a hurry. Recovery from an infestation can take a long time depending on the extent of the damage. And, to top it off, they become adults and eat Momma Q’s roses as some sort of beetle. Certain beetles lay eggs in the soil under your grass. The eggs hatch and the grubs feed on their favorite food. Your grass roots. They dive deep and over winter then come back up in the spring and eat again before becoming beetles and repeating the cycle.

Is that messed up or what?

Now…don’t panic…I don’t know how to break this to you but… you’ve got grubs in your lawn. You probably never knew. But if you haven’t been applying an insecticide on your lawn for grubs chances are, you’ve got ‘em.

Hold on. Don’t go flinging the grub control just yet. Here’s the deal. You’ll probably never see damage from “your” grubs (keep them to yourself thank you very much) if there are not a lot of them in your lawn. A healthy stand of turf, properly mowed, fertilized, and watered can tolerate about 5 white grubs per square foot. If your turf is under stress due to drought, disease, or pretty much anything, the tolerance threshold drops. To know if you have a problem with grubs look for brown patches of grass that seem to be getting bigger as the week progresses (grubs work fast). Not all brown patches on your lawn are grub damage so here’s the next step. Try pulling on the blades of those brown patches. If the grass lifts quickly and comes up like newly laid sod, the roots are gone and chances are you’ve got grubs. Take a closer look, if they are there you’ll find them just under the surface of the soil trying to get out of the light. If there are only 2 or 3 grubs per square foot gather them up for fishing bait if you want but don’t overreact. Keep some water on the area and the grass should recover. Just consider a grub prevention treatment next year.

Grubs

However, if you see more than five in that square foot section, it is time to get rid of them. Head off to your favorite garden supply store and choose from any number of grub controls out there. Apply as directed on the product label then properly care for your lawn as you would normally, keeping an eye on the damaged area(s). If the conditions are right your turf will recover on its own. If you need to reseed…reseed. Simple, easy, no panic here…right? That’s how I roll.

Myth Buster
Here’s a myth I heard from a former employer:
To get rid of moles in a lawn spread grub control. It kills the grubs and the moles leave ‘cause there’s nothing for them to eat. Right?
No…no…no…

OK…it sort of makes sense. This would be true if moles ate only grubs (they don’t), or, if your yard was not on the way to a yard where a mole needed to be (it is). Moles like shortcuts..

The fact is, moles go where moles want to go. They can be an indicator of grubs, but they are not a reliable diagnostic tool. Myths like this have resulted in non-targeted applications of pesticides, which add to potential environmental problems to numerous to count here. Insecticides are for insects only. Use them when you need to, but try to have a little tolerance. Always read the label before applying any pesticide.

Mower Jockey Bonus Question!!!
(No prize just the satisfaction of knowing that you know)

By looking at a white grub, how can you tell what kind of beetle it will become when it reaches the adult stage? (Leave your answer as a comment on this entry.)