Bryan Brown, Ph.D., is the new Integrated Weed Management Specialist
I’m Bryan Brown, the new Integrated Weed Management Specialist at NYS IPM. I’m thrilled to have this opportunity to work with growers and promote IPM solutions for weed management. I came here from the University of Maine, where I compared the economic and ecological effects of several weed management strategies and tested a new cultivation technology that uses several tools, sometimes in tandem, to target the in-row zone.
Integrated weed management
No single weed control tactic is completely effective. And relying on one single tactic is how weeds develop resistance. So what we need to do is integrate more tactics. Attack weeds in as many ways as possible. For conventional growers, a basic step is to use a range of herbicides with different modes of action. Other direct controls include cultivation, flaming, mowing, and biocontrol.
Less direct tactics can also make a huge difference in weed control effectiveness. For example, crop rotation allows for use of different herbicides, fertility, and tillage dates — all of which can be adjusted to combat certain weed species. Likewise, crop cultivar and plant spacing can be altered to maximize competitiveness with weeds, and cover-crop residues can lessen weed emergence. Growers can be even more successful with these practices if they are used to target the biology and life cycle of their most problematic weeds.
When many growers think about weeds, they think of big nasty plants. But I like to encourage growers to think about weed seeds. The number of weed seeds in the soil is very important to the success of weed control tactics. Even if you kill 99% of the weeds in your crop, if you start with 1,000 germinating weed seeds per square foot (yes, that’s common), ten of those weeds will survive and compete with your crop. So depleting the number of weed seeds in the soil is key to effective management. As is often the case in IPM, an ounce of prevention is worth a pound of cure.
How do you reduce the number of weed seeds in the soil? Control weeds before they produce seed, mow crop boarders to prevent seeds from blowing in, and use seed-free fertilizers. You can also create a stale seedbed by encouraging weed seeds to germinate, then killing them before planting. With these techniques, some farmers have sharply reduced the number of weed seeds in their soil, improving their in-season weed control.
I’m especially interested in finding weed management solutions that have multiple benefits. For example, cultivation kills weeds but can also be used to increase nitrogen mineralization, improve water infiltration, and control soil-dwelling pests like cutworms. Cover-crop residue can suppress weeds but it can also increase soil organic matter, interfere with navigation of some insect pests, and reduce splashing of soil-borne pathogens. So perhaps weed management can be integrated with management of soils, pathogens, and insect pests?
Farmers across New York have been struggling with the overabundance of rain this year — meaning that some cornfields never got planted. The result? Weeds have really taken off.
So what? If there’s no crop for weeds to compete with, what’s the danger?
Weeds make seeds, lots of seeds, which could cause a disaster in the next few crops. My research shows that plots where weeds went to seed had 10 times as many weeds the following year. If any of those weeds are herbicide resistant, they’ll drop thousands of herbicide-resistant seeds into farm fields.
But there’s hope. As of late July, most of these weeds are still flowering and haven’t set seed yet. Mowing is a great option to quickly prevent (classic IPM tactic!) the flowering weeds from setting seed. Yes, after mowing those weeds may send up new flowers. So it is important to kill them with herbicides or tillage before planting summer cover crops (check out the Cornell cover crop decision tool) or fall plantings of forage or winter grains.
Doesn’t look like corn, does it? Weed seed production could cause disaster in future crops. But most of the weeds have yet to set seed — so management options are still on the table.
For many problem weeds, most seeds will die in the first couple years in the soil. So if you can keep weed seeds from entering the soil this year, you can really cut down the number of seeds in your soil. In IPM, prevention is the name of the game.
June 7, 2017
by Mary M. Woodsen Comments Off on Invasives are pests! Learn more at our July IPM conference.
We tend to default to bugs — to insects — when we think about pests. But plant diseases and weeds are pests too. And all threaten our fields and farms, our forests and streams, our homes and workplaces.
Pests provide no end of challenges — especially pests that come from afar. Among IPM’s strengths? Researching and crafting powerful ways to cope with them.
Coming up soon, our “Invasive Species in New York: Where We Are and What We Can Do” conference, held just north of Albany at Siena College. The date? July 13, 2017. Join us!
May 16, 2017
by Mary M. Woodsen Comments Off on Keep Off the Grass? IPM for Anyone With a Lawnmower
Now that spring has arrived and you’ve dusted off the lawn mower …
PUBLISHED ON MAY 3RD, 2017, CANTON, N.Y. | Courtesy Paul Hetzler, CCE St. Lawrence County
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.
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.
April 17, 2017
by Joellen Lampman Comments Off on Earth Day: What It Means to Me — and the IPM Connection
“Humankind has not woven the web of life. We are but one thread within it. Whatever we do to the web, we do to ourselves. All things are bound together … all things connect.” — attributed to Chief Seattle
I’m an environmental educator. Have been one all my life. Among my goals? To erase the line between us and the environment. So often we think of nature as someplace we have to travel to. But this separates us from understanding how we affect our world — for good or for bad.
Amazing creatures like this robber fly can be found in your backyard. These excellent predators catch their prey in the air.
At this time of year we are surrounded by appeals to plant trees. Conserve water. Recycle. Save the polar bears. Want to find examples of IPM as an Earth Day theme? Good luck.
Which is too bad. Because the critters and plants that surround us prove that the environment is right here, right now, all the time. The mice in your kitchen are proof that we coexist with nature even inside.
There is no line.
What’s in a name? Is this a weed or a spontaneous lawn flower? The bee doesn’t care!
Basic ecology tells us that all living things need food, water, shelter, and space. Overwater an indoor plant and you will find fungus gnats. Mow your lawn too short and spontaneous lawn flowers will outcompete the grass. Fail to empty outdoor buckets or refresh the water in your birdbath and there will be no shortage of mosquitoes.
When living things move into our space, we typically label them as pests. But this, my friends, is how nature works. When we provide food by leaving dirty dishes around, don’t seal the garbage right, or plant a favorite flower (tulips, say) in an area with no shortage of deer, we might as well just sit back and watch what comes to partake of our offerings.
Who needs to visit Africa? We can watch the circle of life in our backyards! And no need to get all those shots!
I dream of a world where, along with learning about tigers and redwood trees, children learn about our environment through ants and dandelions. For even in the most urban areas, we find ourselves in nature if we only open our eyes and take the time to recognize it.
My appeal? For Earth Day 2017, let’s each learn about one critter we see often – especially one we consider a pest. Where does it fit in the food web? What helping hand have we given it? And to help your exploration, I recommend starting with the NYS IPM Program’s What’s Bugging You webpage.
Erase the line. And have a very happy Earth Day.
p.s. I would love to hear about what you learned. Feel free to contact me at firstname.lastname@example.org with your story!
November 29, 2016
by Mary M. Woodsen Comments Off on Nature’s Herbicides and Lessons from Black Walnut Trees
You’re prepping your garden for winter, muttering about the sapling black walnut trees the squirrels planted on your behalf mere inches away — and the mother tree is in your neighbor’s yard. You know you can’t put off removing them: this might be the last year your loppers can manage the task.
Squirrels are pretty good at finding the walnuts they stashed here and there for winter. But they always miss a few.
Black walnuts get a lot of grief from gardeners. For those with small yards and a great love of tomatoes, the black walnut in a neighboring yard is bad news. But for the moment pretend you’ve got couple of acres, mostly meadow. Pretend the mama walnut tree in the hedgerow out back is framed by a couple of invasive ailanthus (aka tree of heaven) and some elderly pines and sugar maples. Pretend also that goldenrod, quackgrass, and garlic mustard are well-established meadow plants that push their way into your garden every chance they get.
And while you’re at it, pretend you planted buckwheat as a cover crop earlier this summer in some beds where weeds have held sway.
Buckwheat contains three allelopathic chemicals. Plus they grow really fast, out-competing many weeds.
What do all these plants have in common?
They’re alleopathic. That is: they have compounds in their leaves, roots, seeds, or stems that stave off other plants. True, some (think garlic mustard) will only hurt you. But some — buckwheat, for instance — will help. (Hint: click on the fifth bullet point when you open the page.)
NYS IPM’s horticulturalist Brian Eshenaur calls such allelopathic compounds “nature’s herbicides.” If you choose and use them, you might avoid the worrisome traits of conventional herbicides.
What worrisome traits? For starters, the potential for weeds to become herbicide-resistant. If using herbicides is the only way you’ve learned to deal with weeds, you could be in trouble. Could weeds (which, like plant diseases, qualify as pests) also become resistant to nature’s herbicides?
No one is sure. The research has just begun. But by way of example, consider this: insect pests become pesticide-resistant with relative ease. On the other hand, they don’t easily outsmart other bugs that evolved to eat them — which is why biocontrol is a key tenet of IPM.
Worried about walnut trees? Garlic mustard has a nasty reputation of its own.
Yes, black walnuts freely release their plant-suppressive chemicals. But even they have their soft spot.
Here’s what black walnuts are willing to live with:
lima, snap and soybeans; beets and swiss chard; corn; onions, garlic and leeks; parsnip and carrots; cauliflower; parsley; Jerusalem artichoke; melons, squash and pumpkins.
And here’s what they aren’t:
asparagus; cabbage, broccoli and kale; eggplant, peppers, potatoes and tomatoes; rhubarb; peas.
Where walnuts crowd too close, build raised beds with root barriers in the bottom — concrete or rubber patio blocks are one option. Hefty tubs are another. You could raise those beds even higher: built at waist height, they could keep your back happy too.
Worried about those walnut leaves that blow into your yard each fall? Can you add them to your compost? Have no fear. Exposed to air, water and bacteria, their toxic effect is history in two to four weeks. [1.]
Also, take a look at Eshenaur’s Weed-Suppressive Groundcovers. And consider that most of these plants are great when massed in perennial flowerbeds — and could provide welcome food and shelter for pollinators. Multitasking plants? They’re onto IPM.
It’s spring fever. That is what the name of it is. And when you’ve got it, you want — oh, you don’t quite know what it is you do want, but it just fairly makes your heart ache, you want it so! — Mark Twain
For IPMers who answer homeowner questions, what many people want in spring is an answer to dandelions. These in-your-face, bright bursts of yellow are speckling lawns statewide. Homeowners that aren’t yet convinced how important these early flowers are to pollinators want them gone — now. The bad news (or good, depending on your perspective) is: it’s not the best time to do anything. The best time to control broad-leafed weeds is late summer and fall. (We covered this a couple of years ago: Dandelions – Love Them or Leave Them, but Don’t Spray Them.)
We have exactly the opposite problem with wasps and yellow jackets. Now is the time to prevent later problems because their populations are so low in spring.
Identification is important! Is it a bee? Wasp? Bald-faced hornet? This carpenter bee will be managed much differently than other types of stinging insects.
Last autumn a homeowner had “a swarm of bees” take residence in the attic. A pest management professional removed the nest and sprayed an insecticide. When “the bees” were noted this spring, the homeowner worried that they were back for a repeat performance.
The homeowner admitted that he didn’t know if it was bees, yellow jackets, or paper wasps. Identification matters when deciding how to deal with a large active population (you can find pictures of different types of stinging insects here and a video here). But no matter what type of insect is currently scoping out his house, the IPM solution is the same. Find the opening and seal it properly. (Unless it’s a carpenter bee. For more information on them, check out our Get Rid of Carpenter Bees? Yes, Please! fact sheet.)
This soffit was likely damaged when a ladder slipped during a routine gutter cleaning.
In the case of our nervous homeowner, a damaged soffit provides access for all sorts of critters. (The soffit connects the outside wall with the overhang on your roof.) Forget stinging insects. The 1/4″ to 1/2″gap is large enough for bats and mice to enter. (Mice are good climbers.) This is relatively easy to repair by reseating the soffit flush with the bottom. To learn more about sealing openings, you can’t go wrong with the NYS IPM publication Beasts Begone! A Practitioner’s Guide to IPM in Buildings.
When yellow jacket nests are this small, there’s little risk in removing them manually.
Along with inspecting your house and outbuildings for openings that provide access to stinging insects, take the time you’d have spent on dandelions to watch for queens starting new nests under decks and eaves. These small nests can be easily removed using a broom handle or stream of water. (We covered this last year: Inspect for Wasps and Avoid the Sting.)
They’re back! Insect pests, plant diseases, weeds, birds, biting flies — the works. And tracking them year to year is critical. How better to know your options are, this year and in years to come?
So pick up a pencil, smart phone or tablet and write them down on a field-to-field or livestock basis. Write your observations over the course of this summer — each while it’s fresh in your mind. Did potato leafhopper infestations go over threshold in alfalfa? Were corn diseases a problem? Which diseases and what hybrid were infected? Did you have corn rootworm injury? Did you lose wheat to snow mold? Were there new weeds or weed escapes you didn’t expect this year? Got more house flies on your cattle than past years? And bear in mind: cereal leaf beetle is increasing from year to year on wheat. Have you seen it yet?
These records help you better select which management practices to use now and in the future. For example, if you were hit with potato leafhoppers this season and you want to rotate your alfalfa, one management option is to use potato leafhopper-resistant alfalfa. Another example: choose wheat varieties resistant to certain diseases — based on field observations you wrote down last fall.
Likewise, if you have weed escapes you might reconsider your weed control products or even use methods like cultivation Or lots of house flies on your cattle and you sprayed could mean the flies became resistant to the insecticide.
WRITE IT DOWN! Keep records of pests you observe — and their threshold numbers. Because if you wait too long, you might forget what happened.
May 20, 2014 by Joellen Lampman | Comments Off on Dandelions — Love Them or Leave Them, but Don’t Spray Them
It’s May, and lawns across NY are speckled with golden jewels – jewels that provide a valuable early pollen source for our native pollinators and whose leaves and roots are loaded with nutrients. Or — our lawns are splotched by a horrible weed besmirching their beauty, a beacon to shame lax householders.
Harbinger of spring or horrible scourge?
It’s really all about marketing.
If you despise dandelions with a burning passion and feel compelled to do something now, let’s take a quick look at what is going on underground. The dandelion’s long taproot stores energy gathered in the summer through mid-fall. In spring, this energy moves upward supporting new growth and flowers. To kill the plant you must kill the root. Herbicides applied now will kill the tops, but since the momentum continues upward, little to none will reach the root. Later, as the growing season begins to end, energy flows downward to be stored in the root in anticipation of next spring. Herbicides applied then find their way into the root with a greater chance of killing the plant.
So disregard the marketing encouraging you to apply herbicides now for dandelion control. If you’re itching to do SOMETHING, have no fear. There are effective strategies you can do now that will discourage weeds, not just dandelions, while building a stronger, healthier lawn. For more information, visit Cornell University’s Lawn Care Library.