New York State IPM Program

May 16, 2017
by Mary M. Woodsen
Comments Off on Keep Off the Grass? IPM for Anyone With a Lawnmower

Keep Off the Grass? IPM for Anyone With a Lawnmower

Now that spring has arrived and you’ve dusted off the lawn mower …

As a kid of about five, I became suspicious of lawns. In a rare moment of TV viewing, I had seen a public-service ad wherein a bundle of green leafy stuff thudded into an eerily vacant playground while a baritone voice boomed out something like “Grass. We think it’s bad for kids. Stay away from it.” My mom insisted this was “bad grass” which did not grow in our yard. However, she declined to elaborate, which fueled my mistrust. So I kept off the lawn a while.

These days, “bread” is no longer money, “mint” is just a flavor, and the pernicious leafy stuff mostly goes by other names. There is only one grass, and it is almost time to cut it again. Jargon may change, but things like paying taxes and mowing lawns don’t seem to.

To help you, or so they say, a bewildering array of lawn-care products have sprouted at big-box stores and garden centers. It’s easy to spend a lot of dough — I mean money — on fertilizers, weed killers, and seed. But it’s hard to make sense of which products are right for you.

Before you shop, a couple of thoughts to help sort things out.

  • Grass is not for everyone. Or everywhere. If an area does not get 4 or more hours of full sun daily from March through September, trying to grow grass there is a waste of time.
  • Steep slopes and high-traffic zones probably need something other than grass, too.

Keep mower blades sharp — it can help reduce disease, plus it looks nicer and saves on mower gas. (Flickr Creative Commons Brian Boucheron)

Comparison spells trouble. Well not literally, but it’s mighty unfair. Fashion models have airbrush artists and makeup consultants. Golf courses have full-time turf experts and a massive budget. With good information and a little work, we and our lawns can both look good, but let’s not compare with deep-pocketed pros.

Dr. Frank Rossi, a leading Cornell Turfgrass Science researcher, puts it this way:

“Chances are you can grow a pretty good lawn without using insecticides, fungicides, or herbicides. You may even be able to do it using little or no chemical fertilizer… Will your lawn look like a putting green? No… But if you arm yourself with an understanding of what grasses need to thrive, and commit to a long-term plan to meet those needs, you can grow a perfectly acceptable lawn…”

Get the dirt on your soil. If your grass looks bedraggled, fertilizer may not be the answer; in fact, early-season nitrogen can weaken grass and make lawns worse in the long run.

At the very least, get a soil pH test—a pH more acidic (lower) than 6.0, or more alkaline (higher) than 7.0 will hinder plants’ ability to absorb nutrients. The majority of samples I get at the office have pH values too high for healthy lawns, sometimes 100 or even 1,000 times too alkaline due to annual lime treatments. Lime is only good if it’s needed.

If it’s been over three years since the soil was tested, you might want to invest in a lab analysis. For under twenty bucks you can get nutrient levels with specific recommendations, plus pH and salt content. This last item may seem odd, but fertilizers, herbicides, wood ash and deicing agents are all sources of salt — which can damage soil structure, harm microbes, and aggravate water stress.

Only fertilize based on soil test results, and only use nitrogen in the fall.

Nature abhors a vacuum, which is why I keep mine hidden away indoors — no sense offending nature if you can avoid it. This hatred of emptiness means that if you don’t re-seed bare or weak spots in the lawn, Nature will fill it with whatever is handy — probably weeds.

Edging along the sidewalk or driveway may produce the look you want, but it also produces a lot of bare earth, so if you have a weed issue, especially crabgrass, breaking this habit will give you an edge on weed control.

Another type of vacuum is a close-cropped lawn. Not only does close mowing cause weak, stunted grass roots (and thus plants), it allows the sun full access to the soil. This gives weeds a tremendous advantage.

Have trouble with ground ivy? Put away the vacuum. Stop shaving the earth and start mowing the grass.

The most important thing you can give your lawn is more of its hair. Studies show that changing to a grass height of 3.5 inches leads to a vast improvement in lawn health. Leaving grass longer will greatly reduce weed pressure, lawn diseases, and fertilizer requirements. Perhaps the most dramatic change with longer grass is a lasting drop in weed population.

If you need to use herbicides to reduce weeds, follow the label instructions closely. Some broadleaf (selective) herbicides contain chemicals that could stress or injure trees. Pre-emergent herbicides inhibit weed germination, and are used for crabgrass control. Apply pre-emergent products around the time forsythia flowers are starting to drop.

Another tip is not to mow more than a third of the grass at a time. For example, to maintain a 3.5-inch turf height, mow before the grass gets over five inches high. Try to keep the blades sharp — it can help reduce disease, plus it looks nicer and saves on mower gas. And it almost goes without saying that grass clippings belong to the lawn, not the landfill. Leave the clippings—that’s your fertilizer.

White grubs — we have five species in northern NY — can become a problem if there are more than ten per square foot of lawn. Several nontoxic and low-toxicity treatments have come on the market in the past few years, but timing varies for all of them. Milky spore treatment is safe, but is not effective up north due to cool soils. You can also use beneficial nematodes to kill grubs. 

There are many solid lawn-care resources out there, but always check the source, which should be from .edu or .gov sites. Cornell Senior Extension Associate Lori Brewer has assembled the work of many experts, including Dr. Rossi, into a comprehensive 47-page book entitled “Lawn Care,” which is free at http://hort.cornell.edu/turf/lawn-care.pdf

I think it will contribute to a better world if we teach our kids to stay grounded and let the grass get high.

See more at Morning Ag Clips.

These nematodes Hetzler mentions — beneficial organisms — are key to good IPM. In fact, good IPM embraces every concept Hetzler stands by. With IPM, prevention is always the best cure. And remember: even herbicides are a type of pesticide, because weeds are pests too. If you’ve ever spent a whole day weeding a not-that-big garden, you know that sometimes weeds are the most difficult contenders we face. — ed. MW.

September 30, 2014
by Joellen Lampman
Comments Off on IPM for Dead Grass SOS

IPM for Dead Grass SOS

Grub damage is showing up in New York later this year than usual, so don’t let your guard down just because it’s October. Still, how do you know if it’s grubs — or something else? One test: if you can loosen the sod with a trowel or garden fork, then peel it up like a carpet, you’ve got grubs. Monitoring, though, is your best bet, and here’s how (pdf) — or watch this video.

Recently I visited distressed homeowners with a lawn so badly infested, I could brush the turf away with a swipe of my fingers. They didn’t want to use pesticides, but they also didn’t know the proper way — mow right, feed right, and water right — to care for their lawn. Given how sandy soil their soil was, their turf showed drought stress despite 2014’s rainy summer. And they had never fertilized.

Home lawn infested with grubs

Stressed grass is more likely to succumb to pests like white grub

My IPM recommendations:

  • Mow Right: Raise the height of cut on the mower to its highest level and sharpen the blades regularly.
  • Feed Right: Provide a fall nitrogen fertilizer application. Conduct a soil test to determine if other nutrients are also needed.
  • Water Right: Most grasses need one to two inches of water per week. When nature does not provide, it is important to provide supplemental water.

To tackle the grub issue, research at the State University of New York at Delhi has shown that turfgrass aerators can lower grub populations, sometimes as much as 90 percent. Aeration can also help better your success with overseeding. Beneficial nematodes are another, albeit more costly, choice for grub control.

Grub infested home lawn

Grubs had so badly damaged the roots that I could brush the grass away with my fingers.

While early fall is an excellent time to overseed with a drought-resistant turfgrass, when you have bare areas like this homeowner and have access to water, overseeding now will help get a jump on the weeds and help stabilize the soil. For these homeowners’ sandy, sunny location and their need for a low-maintenance lawn, Cornell recommends either a 100% tall fescue blend seeded at a rate of 7 to 10 pounds per 1,000 square feet — or a mixture of 65% fine fescue blend, 15% perennial ryegrasses, and 20% Kentucky bluegrass blend at 4 to 5 pounds per 1,000 square feet.

For more information, take a look at our Lawn Care Without Pesticides by Frank Rossi, Professor.

August 27, 2014
by Joellen Lampman
Comments Off on Punching Out Grubs

Punching Out Grubs

Cutting grass roots to the quick — that’s a grub’s stock in trade. But pesticides cost money and time — let alone potential health hazards, whether to ecosystems or us. Cutting grubs to the quick? Now, there’s an idea.

Aerators can often be rented at local hardware stores.

Aerators can often be rented at local hardware stores.

Groundskeepers and savvy homeowners use aerators with their sharp tines to break up hard, compacted soil, letting life-giving oxygen and water deeper into the earth. But those tines have another function, though not by design. They’re like tiny spears, meaning that a grub in the wrong place at the wrong time is a goner. (Aerators can be rented.. In the NY Capital region, I am able to rent an aerator at my local garden store for $40 for four hours and $80 a day. To find one in your area, try Googling: aerator rental “your town”).

grub life cycle

Big grubs make the best targets. And the research … well, just read on.

Research at the State University of New York at Delhi has shown that yes, turfgrass aerators can lower grub populations, sometimes as much as 90 percent — depending, of course, on conditions that vary from site to site and year to year. Building on that, NYS IPM-funded research at SUNY Delhi looked at which cultivator designs do best against grubs.

Results? All aerators can cut grub populations — though the old standard hollow-core aerators did best in these trials. And it’s an inexpensive tactic if you have the equipment. With this information in hand, you can plan your aerate with grub management in mind. Ideally you’d time a tactic like this for when grubs are big enough to easily impale, yet not so big they’ve already dug deep to survive the winter.

So should you get punchy? Our video shows you how to assess your lawn and scout for grubs. If you find 10 grubs per square foot, now is the time! Grubs are pretty big and still close to the surface in late August so aerating might be just the ticket.

For more information, visit www.nysipm.cornell.edu/whats_bugging_you/grubs/default.asp and www.nysipm.cornell.edu/publications/grubs.

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