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Grub Damage? Try Beneficial Nematodes


With an unusually mild winter in many areas of North America, many homeowners are lamenting lawn damage due to grubs — or more specifically from the creatures like birds, skunks and moles that like to eat the grubs.

When people ask me what to do about the critters rummaging for grubs, I usually facetiously say, “Cheer them on!” Moles, especially, are nature’s way of keeping the grub population in balance.

Of course, that’s not the answer folks want to hear. So my second best answer is always: beneficial nematodes. These are microscopic organisms that can be applied to the soil from a hose-end sprayer. They tunnel into the ground in a search-and-destroy mission against the grubs. The nematodes are safe, effective and, if your lawn isn’t too big, they won’t break the bank.

Our mailorder sponsor GardensAlive is one of the best and most reliable sources of the nematodes. But depending on where you live, don’t rush out to buy them now. The soil needs to be warm, ideally 60-70 degrees, before application. Here in the Northeast of the U.S. where I’m located, the ideal time for application is just before the grubs emerge from the soil to morph into their beetle phase. That’s typically sometime in early to mid June.

Some folks do swear by milky spore treatments for grubs. I know some rose growers in Maine who applied the milky spore several years ago and haven’t had any Japanese beetle issues with their roses ever since. There are two primary issues with the milky spore, however. The first is the innoculation period of two to three years. In the meantime, you may have to deal with a lot of grub damage — unless you treat with the nematodes while you’re waiting for the milky spore to kick in. The good news with the milky spore is that you do get several years of effective control.

The second issue with milky spore concerns applications in cold climates. At Zone 5 or below (where winter temperatures can drop below minus 20 Fahrenheit), the milky spore doesn’t survive.

The best news for organic gardeners and lawn care folks is that grub control is rarely necessary when landscapes are tended naturally. Roots grow more deeply in an organic environment; deeper roots can withstand damage from grubs far more effectively than shallow roots.

About The Author

Paul Tukey

An international leader of the green movement, Mr. Tukey is a journalist, author, filmmaker, TV host, activist and award-winning public speaker, who is widely recognized as North America's leading advocate for landscape sustainability and toxic pesticide reduction strategies.

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