>War of The Roses
>War of the Roses:
Beetle vs. Nematode
By STEVE STECKLOW
July 23, 2008
I ignored it when they skeletonized the leaves of my semidwarf plum tree. I remained silent when they infested the rose bushes. But when they ravaged my prized raspberry patch last summer, it was time to take action.
I declared war. Biological war.
If you garden in the eastern U.S., you’re probably familiar with the metallic-green-and-copper-bodied winged creature known as the Japanese beetle. Since arriving in New Jersey from Asia nearly a century ago, these half-inch-long predators have spread to more than 30 states, wreaking havoc on the foliage of fruit and ornamental trees, shrubs, vines and vegetable crops.
Watch as organic gardener Steve Stecklow declares war on the Japanese beetles chomping on his garden. When nematodes fail, he tries Grub-ex. Just don’t tell his wife.
And if that’s not bad enough, Japanese beetles in the larval stage — commonly called white grubs — drill down into the soil to feed on grass roots, creating brown patches on pristine front lawns. The U.S. Department of Agriculture calls it “the most widespread turf-grass pest in the United States.” Efforts to control it cost more than $460 million a year, according to the agency.
As a fledgling organic gardener, my beetle-control options were limited. Naturally, my wife banned me from exercising the nuclear option: poisons like Bayer Corp.’s 24-Hour Grub Killer Plus, which promises to deliver “overnight results.”
My organic options were less toxic — and a lot longer term. I had tried Japanese beetle traps with little success. These yellow plastic contraptions lure the beetles with floral scent and the insect’s own sex attractant, or pheromone. Intoxicated by the aroma, they smash into a piece of yellow plastic, then fall into a bag.
The problem is that installing a trap is like issuing a summer party invitation to every Japanese beetle in the neighborhood. The insects arrive from far and wide, and, not surprisingly, often prefer your raspberry patch to suffocating in a plastic bag.
Then there’s the milky spore solution. Here’s how it’s supposed to work: You spread the spores on your lawn. The grubs eat them. The spores turn into bacteria, which multiply. Within a few weeks, the grubs die, each releasing billions of new spores back into the soil.
It all sounds great until you learn that it can take as many as five years — especially in colder climates like New England where I live — for the spores to get established in your lawn. In addition, the granular variety, which is the easiest to apply, requires six treatments over two years.
Sorry, but I’m not that patient. So I opted this year for a more rapid biological weapon — beneficial nematodes.
I first learned about using these parasitic, worm-like organisms from Gardener’s Supply Co. in Vermont, which, among other things, sells live ladybugs and ready-to-hatch praying mantises to devour garden pests like aphids. The idea is that it’s environmentally safer to employ a pest’s natural predators than to spray pesticide. With the increasing interest in organic gardening, there’s now a cottage industry of beneficial bug mail-order suppliers.
To combat Japanese beetles, the Gardener’s Supply Web site promotes “Grub Guard” — microscopic, “naturally occurring” nematodes that attack beetle larvae within 48 hours and keep working all summer until they, and the grubs, perish. “Grub Guard Controls Your Garden’s Worst Enemy,” the site proclaims.
That sounded pretty good to me, so I decided to order one million — enough to cover 2,000 square feet — for $19.95. The guards arrived in mid-April, packed together in a dime-size circle on a damp blue sponge. Not having an electron microscope around the house, I didn’t take the time to count them.
The instructions called for mixing the nematodes in a bucket of water and applying them to the lawn and garden with a hose-end sprayer at dusk or on a warm, rainy day. It warned that sunlight can kill them.
So there I was one evening, spraying invisible nematodes all over the garden and front lawn. My wife and teenage son rightly told me I was nuts.
Japanese beetles don’t emerge until summer so there was no way to know if the nematodes were attacking the grubs. All I knew was that nearly every time I stuck a spade in my garden to plant something, I discovered another grub.
By mid-May, I was growing nervous. I’d been looking at the Web site of Gardens Alive!, a garden supply company in Indiana. They were advertising “Grub-Away Nematodes” which the site claimed were superior to other varieties. “While other beneficial nematodes wait passively for prey, ours move up to 10 times farther and much deeper into the soil,” it explained. “Grub-Away Nematodes also have a special ‘tooth’ that burrows into their prey, allowing faster control of pests.”
What worried me wasn’t that my million nematodes were toothless; about half of them, in fact, were of the same strain as “Grub-Away.” But Gardens Alive! claimed that a garden area of 200 to 300 square feet required 10 million nematodes. Our garden alone is larger than that, never mind the lawn. What if the one million I had sprayed weren’t nearly enough? (A spokeswoman for Gardener’s Supply later told me that its nematodes “multiply,” so fewer are needed.)
I ordered 10 million more nematodes for $29.95 as an insurance measure. They didn’t arrive for a few weeks because they were on back order. Obviously, a lot of other organic gardeners were waging war against Japanese beetles, too.
The new nematodes came on a thicker sponge with similar instructions. I sprayed them on the garden, this time right after a rain.
That weekend I happened to be in a Costco, where I saw the store was selling a large package containing three giant Japanese beetle traps, the largest I’d ever seen. I walked past the display, then came back and threw a package in my cart. I stuck the receipt in my wallet, figuring I’d return it if the 11 million nematodes in my lawn and garden got the job done.
On July 6, I spotted my first Japanese beetle. It was sitting on a leaf of a tomato plant. In the past, the pests had ignored the tomatoes. I took this as a bad sign. A couple of days later, my wife spotted a half-dozen on a rose bush.
Out came the giant Japanese beetle traps. As soon as I removed the attractants from the bag — even before I set the traps up — beetles began nose-diving from the air. They weren’t the Japanese variety, but a flying brown beetle I’d never seen before. By day’s end, the three plastic bags under the attractants were crawling with beetles, including the Japanese variety.
It seemed that my nematodes weren’t doing the trick. I called Gardener’s Supply, where a spokeswoman explained that its nematodes may not have multiplied all the way to the outer edges of my property, adding, “You still have neighbors that have Japanese beetles that will be flying into the area.” A “master gardener” at Gardens Alive! also blamed my neighbors’ beetles.
In fairness, it’s a bit too early in the growing season to raise the white flag. Japanese beetles hang around here until August. And so far I’ve spotted only a few among the raspberry bushes. Maybe they’ll be spared this year.
If not, there’s always the nuclear option. Just don’t tell my wife.
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