New York State IPM Program

November 7, 2017
by Mary M. Woodsen
Comments Off on Pollinators, awards — and IPM

Pollinators, awards — and IPM

Just one short week ago, we celebrated the College of Agriculture and Life Science at Cornell University’s Outstanding Accomplishments in Extension and Outreach Award. This award honors a team effort that benefits an important segment of the population or area of the state.

It takes teamwork — whether you’re a bee or a researcher. (Photo Sasha Israel)

New York, like the rest of the world, is highly dependent on the hundreds of species of crop pollinators that collectively contribute roughly $170 billion a year to the global economy. Many are in decline and under threat in New York and elsewhere.

That’s why Dean Kathryn J. Boor ’80 recognized the Cornell Pollinator Health Team for their outstanding outreach accomplishments in a ceremony that celebrated research, extension and staff excellence.

Pollinator Team at the 2017 CALS Award Ceremony

On hand to accept from Dean Kathryn Boor (L) were (L-R) Jennifer Grant, Bryan Danforth, Dan Wixted and Scott McArt.

The seven-member team includes entomologists, extension  outreach specialists and pest management experts  — one being NYS IPM‘s director Jennifer Grant.

The team provides critical extension and outreach on pollinator declines, including information on

  • optimal habitats for honey bees, native bees, and other pollinators
  • diseases that afflict bees
  • how pesticides affect bees — other pollinators too
  • what to do when your honey bees are in decline

Hi. I’m a hover fly and I pollinate lots of plants too. Plus my larvae eat aphids for breakfast, lunch and dinner. And no, I won’t sting you. (Photo credit Susan Ellis.)

With its focus on extension and outreach, the team has given more than 70 extension talks over the past three years in New York and elsewhere on pollinator health, bee diversity, integrated pest management practices and pesticide recommendations that minimize risks to bees — to all pollinators, in fact. Their audiences have included beekeepers, farmers, and lawmakers — as well as state and national organizations such as the New York Farm Bureau, the Audubon Society and Future Farmers of America.

“In three short years, the work of this team has made a notable impact both in scope and relevance to beekeepers,” Boor said at the ceremony. “The pollinator health team represents a model for how collaboration among different units at Cornell can lead to highly integrative and creative extension and outreach.”

November 1, 2017
by Mary M. Woodsen
Comments Off on It’s (still) tick season — and will be evermore

It’s (still) tick season — and will be evermore

Sorry to bring up a sore subject, but it’s still tick season. And will be all year round. What … during winter? Really? Yes. But for starters here’s your pop quiz:

A tick’s lifespan is

  • three months
  • ten months
  • twenty-four months (that is, about two years)

The best way to remove a tick is to

  • swab it with nail polish
  • hold a hot match to its behind
  • pull it straight up with fine-point tweezers

Even 15 million years ago, it was tick season. Trapped in amber, this tick carries Lyme-causing bacteria. (Photo credit Oregon State University.)

But back to our intro. Here’s the scoop: an adult female that hasn’t yet managed to grab hold of a large animal (think deer — or person) to get that all-important blood meal (can’t lay eggs without it) doesn’t want to wait around till a sunshiny summer day next year, because by then its number is up. Besides, the mice, chipmunks or birds it fed on earlier in its life cycle have only so much blood to go around. So that tick stays just below the soil where tall meadow flowers or low shrubs grow. Waiting. Waiting for a thaw barely long enough for it to scramble up one of those stems.

Waiting for the cues that tell it a warm-blooded animal is at close range. An animal that might be you.

And now for a look at our quiz. A tick’s lifespan? Your answer is (drumroll) C: upward of two years. Here’s how it works: Ticks spend a lot of time in dormancy, aka diapause. Eggs are laid in spring, tucked away out of sight. If some critter doesn’t find and eat them, they’ll hatch during summer as larval ticks (seed ticks, they’re sometimes called). Larval ticks are not infected with Lyme when they hatch — indeed, they’re pure as the fallen snow.

Meanwhile if likely hosts — those mice, chipmunks or birds — wander by, the ticks latch on. And if a host is already infected with Lyme disease or any of its nasty co-infections, those larval ticks, pure no more, are infected too.

Look close and you’ll see that spring, summer, fall, winter … every season is tick season. (Image credit Florida Dept. Health)

Larvae that make it this far morph into nymphs, and it’s diapause season again as the nymphs wait it out till the following spring. Assuming these ticks are now carriers —and about 25% will be — spring is the worst time of year for us. Because these ticks are tiny enough (the infamous poppy-seed stage) that they’re easy to overlook. If you get bit, ipso facto — you get Lyme (and quite possibly a co-infection too).

Things slack off in late summer as surviving nymphs enter a diapause that lasts till the following spring. But you can’t let down your guard, since by mid-fall through winter you’ve got those adult ticks to consider. The good thing (if “good thing” there is)? While half of these sesame seed-sized ticks are infected, they’re also easier to spot and remove.

Our second  quiz item? If any of these strike you as valuable folk wisdom, strike the valuable part and know it ain’t so. Nail polish? Matches? Don’t even think of it. Those first two items are just likely to tick that tick off — and it’ll vomit its gut contents into you in its hurry to get out. That is, if it can get out quickly; if it’s really drilled in, it has downloaded a cement-like substance to anchor itself. It takes some doing to disengage, however persuasive the nail polish, burnt match, or myriad other folklore remedies. (Twisting it is another no-no that comes to mind, mainly because someone asked me about it mid-way through this post.)

Pointy tweezers, held right against your skin and gripping the mouthparts, are the way to go. (Image credit tickencounter.org)

If you value your health, get yourself some pointy tweezers, sold for needlepoint and other crafts, and carry them with you always in your bag, backpack, or whatever you haul around. Grasp that tick as close as you can get to your skin and pull steadily. Did its mouthparts remain glued within? Not to worry — the tick will feed no more. And before too many days go by, your exfoliating skin (that’s when the top layer of skin cells drift away) will exfoliate them in turn.

With ticks, prevention can include everything from doing routine tick checks to wearing repellent clothing when you’re outdoors — regardless the season. And you can’t do much better than this for advice about dressing right.

Meanwhile here’s your catchphrase: 32, ticks on you. “32” as in 32°F. Stay watchful — and stay safe.

September 28, 2017
by Joellen Lampman
Comments Off on In praise of messiness

In praise of messiness

KEMPTVILLE, ONTARIO. — On my twice-monthly drive on Highway 416 between Prescott and Ottawa, I pass the sign for Kemptville, a town of about 3,500 which lies roughly 40 km north of the St. Lawrence. It has a rich history, and no doubt is a fine place to live, but one of these days I need to stop there to verify that Kemptville is in fact a village of surpassing tidiness. (It’s Exit 34 in case anyone wants to take some field notes and get back to me.)

Most of us would prefer not to live in totally unkempt surroundings, but Western culture may have taken sanitation a bit too far. Claims that cleanliness is next to godliness have yet to be proven by science, but research does indicate a neat, well-coiffed landscape is bad for bees and other pollinators.

Dandelions are an essential early-season flowers for our 416 species of wild bees in New York.

With all due respect to honeybees, they are seldom required to produce fruits and vegetables. Please don’t spread this around, as I do not want to tarnish their public image. But the fact is that wild bees, along with other insects and the odd vertebrate here and there, do a bang-up job pollinating our crops, provided there are enough types of wild plants (i.e., messiness) around to keep them happy for the rest of the season.

As landscapes become neater and less diverse, wild bees cannot find enough natural foods to keep them in the neighborhood for the few weeks of the year we’d like them to wallow around in our apple or cucumber flowers. In sterile, highly manipulated environments like almond groves and suburban tracts, honeybees are critical.

Dr. Scott McArt, a bee specialist at Cornell’s Dyce Laboratory for Bee Research, says there are an estimated 416 species of wild bees in New York State. When I estimate stuff, the numbers tend to be less exact, such as “more than three,” but I’ve met Dr. McArt, and I trust him on this count. Dr. McArt is quick to point out that wild critters take care of things just fine in most places. He has cataloged exactly 110 species of wild bees visiting apple blossoms in commercial orchards, and in the vast majority of NYS orchards studied, honeybees have no bearing on pollination rates. My object is not to malign honeybees, but to point out that if we learn to live with a bit more unkemptness, we will improve the health of wild bees, wildflowers, food crops, and ourselves in the process.

Dr. McArt has cataloged exactly 110 species of wild bees visiting apple blossoms in commercial orchards, and in the vast majority of NYS orchards studied, honeybees have no bearing on pollination rates. There was a presentation about it at the 2015 Pollinator Conference.

Messiness also takes pressure off managed honeybees, an increasingly fragile species, by providing them a rich source of wild, non-sprayed nectar and pollen. Orchardists do not spray insecticides when their crops are flowering because they know it will kill bees. But many fungicides, which are not intended to kill insects, are sprayed during bloom. One of the unexpected findings of research done through the Dyce Lab is that non-lethal sprays like fungicides are directly linked with the decline of both wild bees and honeybees. But banning a particular chemical is not a panacea—the situation is far more complex than that. What is needed to save bees of all stripes is a real change in mindset regarding landscape aesthetics.

This garden at Bethpage State Park Golf Course is an excellent example of entropy. Primarily established with native wildflowers, there are also a significant number of volunteers. NYS IPM staff found over 100 different species of insects, primarily bees and wasps, taking advantage of the bounty.

Increasing the entropy on one’s property is as easy as falling off a log (which of course is a literal example of increased entropy). Pollinators need plants which bloom at all different times, grow at various heights, and have a multitude of flower shapes and structures. For greater abundance and diversity of wild flowering plants, all you need to do is stop. Stop constantly mowing everything. Choose some places to mow once a year in the late fall, and others where you will mow every second third year. Stop using herbicides, both the broadleaf kind and the non-selective type.

Before you know it, elderberry and raspberry will spring up. Woody plants like dogwoods and viburnums will start to appear. Coltsfoot and dandelions, essential early-season flowers, will come back. Asters and goldenrod (which by the way do not cause allergies), highly important late-season sources of nectar and pollen, will likewise return.

Despite their unassuming flowers, Virginia creeper attracts a large number of pollinating bees and wasps. Photo: Joellen Lampman

Wild grape, virgin’s bower, Virginia creeper and wild cucumber will ramble around, without any help whatsoever. However, you may choose to help this process along by sowing perennial or self-seeding wildflowers like purple coneflower, foxglove, bee balm, mint, or lupine. Even dandelion is worth planting. You’ll not only get more wild pollinators, you’ll also see more birds. Redstarts, tanagers, orioles, hummingbirds, catbirds, waxwings and more will be attracted to such glorious neglect. No feeders required.

I strongly advocate for more chaos in the plant department, even if the local Chamber of Commerce or Tourism Board frowns upon it. Remember, just because you’re an unkempt community doesn’t mean you have to change the name of your town.

Many thanks to Paul for letting us share his piece! For more information on protecting pollinators and enhancing their habitat, visit the New York State Integrated Pest Management Program’s pollinators webpage.

July 20, 2017
by Abby Seaman
Comments Off on Got late blight in your garden? Here’s what to do.

Got late blight in your garden? Here’s what to do.

An upside of last year’s dry growing season is that we had no reports in New York of late blight, the devastating disease of tomato and potato.

But 2017 is shaping up to be a very different season. We had our first late blight report in Erie County July 10th — and another one from Livingston County on the 13th.

Late blight has a toehold on your tomatoes. Act now.

Anyone growing tomatoes or potatoes should be aware of the risk and be alert for the first signs of late blight infection. Learn how to identify late blight — good IPM! — and distinguish it from other diseases with the Distinguishing Late Blight from Other Tomato and Potato Diseases and Identifying and Scouting for Late Blight on Farms videos.

You could also take a sample to your local Cornell Cooperative Extension office for diagnosis. Find your local Extension office at the Cornell Cooperative Extension web site.

Preventing Late Blight

The pathogen that causes late blight in the U.S. overwinters only in living potato tubers. To prevent late blight

  • be sure no infected tubers get through the winter alive
  • immediately destroy any plants that come up from potatoes that didn’t get harvested last year
  • plant certified seed potatoes.

Yet even if you do everything to prevent late blight from getting started in your garden, spores from nearby infected plants can be carried through the air to land on your tomatoes or potatoes.

Plant tomato varieties resistant to late blight to help prevent it from killing your plants — and prevention is a key tenet of IPM. Find a list of late blight resistant varieties in the article Late Blight Management in Tomato with Resistant Varieties.

Some varieties of potato — Elba, Kennebec, Sebago, and Serran among them — have some resistance; they will slow but not prevent late blight infection. If late blight becomes prevalent in your area, fungicides can protect your plants.

But act quickly, applying fungicide before plants are infected. Why? Products available for gardens cannot cure existing infections.

Want to track where late blight has been found? Sign up for text or email alerts on the usablight.org web site.

What to do if you find late blight in your garden

Take immediate action — otherwise you’ll be a source of infection for other gardens and farms. Infected plants release hundreds of thousands of spores that move on the breeze. But first confirm that what you have is late blight and not another tomato or potato disease.

County Cornell Cooperative Extension offices can offer a diagnosis or can submit a sample through the usablight.org web site. Reporting your find on usablight.org and submitting close-up and in-focus photos can sometimes be enough for us confirm a late blight infection.

Though we hate to say it, if the rainy conditions we’ve had so far this season continue, some of us will lose the battle against late blight. If that happens, you can find some suggestions for how to prevent your garden from being a source of infection for the whole neighborhood in the video What to Do if You Find Late Blight in Your Garden.

Good luck! And here’s hoping late blight doesn’t find you this season.

Lesions on leaves, stems, and fruit — it’s late blight in full bloom.

June 28, 2017
by Karen English
Comments Off on Pruning berry bushes to minimize destructive pest habitat

Pruning berry bushes to minimize destructive pest habitat

Examine your caneberry (raspberries and blackberries) plantings for conditions that promote spotted wing drosophila (SWD) infestation and take steps to eliminate them. Although we cannot change the weather, we can alter conditions in the planting to reduce the cool, dark, humid areas preferred by SWD. Pruning and training systems can help maintain an open canopy to increase sunlight and reduce humidity. This will make plantings less attractive to SWD, will reduce SWD activity, and will improve spray penetration and coverage.

Spotted wing drosophila (SWD), an invasive insect originally from Asia, was first reported in the Northeast in 2011. Since 2012, adult SWD have been causing wide-spread injury to some berry crops in NY where management measures are not being used. Unlike most fruit fly species, SWD attack ripening and ripe fruit.

Bumblebee on raspberry

Bumblebee pollinating pruned and trellised raspberry.

Pruning tactics for caneberries have been developed to achieve excellent fruit yield and open the canopy. Knowing different pruning strategies will help you manage SWD. Added benefits include improved fruit color and flavor promoted by sunlight, easier picking by workers and customers, and easier weed management.

Caneberries (brambles) grown in the Northeast include red and black raspberries and blackberries; all are susceptible to SWD infestation. However, fruiting season differs among cultivars, which influences the risk of infestation.

  • Summer bearing varieties develop berries on floricanes that grow the prior year and overwinter. Fruit ripens and is harvested in early to mid-summer, prior to SWD population buildup, lowering the risk of infestation.
  • Fall bearing varieties develop berries on primocanes that grow, flower, and fruit in the same year. Fruit ripens and is harvested in late summer and early fall when SWD populations are high and risk of infestation is extreme.
  • Plants developing berries on floricanes and primocanes haven’t had floricanes removed after fall fruiting. Fruit ripens and is harvested from early to mid-summer on the floricanes and from late summer to early fall on the primocanes. The risk of SWD infestation will be low early in the harvest season and will increase as the summer progresses and the SWD population builds up.

Pruning suggestions for summer bearing varieties

Summer raspberries – maintain 4-5 healthy floricanes per foot of row.

Blackberries – maintain 3-4 healthy floricanes per foot of row.

Black raspberries – maintain 6-8 floricanes per hill.

Everbearing – maintain 4 primocanes and 4 floricanes per foot of row.

Floricanes should be held upright with a trellis to facilitate spray coverage and air circulation. Holding fruiting canes to the outside on a V-trellis will keep them to the outside of the growing primocanes and facilitate spray coverage and harvest.

Prune out the smallest primocanes beginning when they are 12 to 18 inches high to select and keep the biggest and best canes. Keep a few more than the suggested cane density per foot of row or per hill. Begin removing spent floricanes in July along with any late emerging primocanes. In November, laterals on black raspberry and blackberry primocanes can be cut back to 3 or 4 buds.

Pruning suggestions for fall bearing varieties

Maintain 4-6 primocanes per plant on a trellis.

Encourage early fruiting by placing row covers over the row after mowing in the spring. Remove the row covers when the primocanes are 18 inches tall. This will bring on flowering about two weeks early and help avoid or minimize SWD damage.

References

Nourse, N. 2015. Raspberry pruning timeline. Nourse News. Spring:2-3. http://noursefarms.com/resources/newsletters/spring_2015.pdf

Pritts, M. 2013. Horticultural strategies for living with SWD. New York Berry News 12(10):1-2. http://www.hort.cornell.edu/fruit/nybn/newslettpdfs/2013/nybn1210.pdf

Acknowledgement

This blog post, written by Juliet Carroll (NYS IPM), was originally posted as Pruning caneberries to minimize SWD habitat within the planting here on June 27, 2017.

June 19, 2017
by Mary M. Woodsen
Comments Off on It’s Pollinator Week. Read All About It.

It’s Pollinator Week. Read All About It.

It’s summer; the goldenrods will be blooming soon, with bumble bees buzzing around them. Photo courtesy David Cappaert.

When we think about bees, we mostly think about honeybees … a European native brought here by the very first colonists. Now honeybees are struggling, hammered by a constellation of 20-plus diseases and parasites — not to mention a range of insecticides and fungicides.

About 450 species of wild bees also populate our fields and gardens. They have similar problems. And they’re losing habitat.

This is serious business: we depend on pollinators for at least one-third of our food supply. Altogether, these pollinators boost New York’s economy by $1.2 billion.

And consider all those other critters: flower flies and hover flies, wasps, butterflies and moths; even hummingbirds — they are legion, they work hard for their living; they help too.

NYSIPM funds educational projects like this. Photo courtesy Jen Stengle.

What to do? For starters, we can make all these helpers even more at home in our fields and gardens.

Indeed, it’s through bringing together everything IPM knows about host and pest biology and habitat; about pesticides and their EIQs; about habitat protection and biodiversity — these are the things we excel at, and these are what we’re putting into play now to find the answers we need.

Ah … answers. Such as?

Since protecting non-target organisms is core to IPM, we helped advise the governor’s Pollinator Task Force in crafting a Pollinator Protection Plan — itself informed by a national strategy to promote the health of all pollinators. And our flagship IPM Annual Conference highlighted an IPM problem-solution approach for the 100 participants: farmers, consultants, beekeepers (but of course), landscapers, researchers, policy makers, greenhouse growers, and more.

Check it out — not only because you care about your health and your food supply, but because you care about this beautiful world we live in.

June 7, 2017
by Mary M. Woodsen
Comments Off on Invasives are pests! Learn more at our July IPM conference.

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!

March 29, 2017
by Mary M. Woodsen
Comments Off on Earth Day IPM for birds and bees — and native plants that nourish them

Earth Day IPM for birds and bees — and native plants that nourish them

We’re starting this post with a detour. But we have little choice. Before you go shopping around for landscape plants, you need to know the backstory.

Invasive plants, trees, shrubs, vines and flowers, many of them brought from afar because yes, they’re lovely in the landscape, have become a bit too much of a good thing. In part it’s because they didn’t evolve here. That could mean the critters — mostly insects or pathogens that co-evolved with them and helped keep them in check — don’t live here. Where that’s the case, there’s little here to naturally keep them in check.

OK, sumac berries aren’t all that tasty. But for migratory songbirds powering their way north, they offer needed nutrients. (Photo credit Mary Holland)

True, not all imported plants are invasive. But it’s all too easy to dig up a seedling or sucker from an invasive when you don’t know the extent of the problem. Which is partly why New York passed the Invasive Species Prevention Act in 2012.

Native plants, on the other hand, are less likely to get out of hand. Plus they can encourage biological control by attracting predatory or parasitoid insects — the good guys that prey on insect pests. And promoting these good guys is key to good IPM.

So with Earth Day in mind and planting season at hand, let’s note this threesome of invasive trees: angelica tree, sycamore maple, and Amur cork tree. These landscape trees are no longer for sale in New York. For a threesome of attractive natives that can fill their place — while helping the birds and bees — consider the merits of (drum roll) staghorn sumac, Juneberry, and white fringetree.

As we speak, migrating birds are stripping last year’s crop of staghorn sumac seeds, now mostly dry and withered but still nourishing, to power their northbound flight. Love birds? Your sumac planting will benefit robins, bluebirds, thrushes, catbirds, cardinals, chickadees, starlings, wild turkey, pileated woodpecker — and that’s just for starters. Soon its tiny yellowish flowers will attract bees and butterflies. Fiery autumn color. Drought resistant, and an excellent soil stabilizer on hillsides.

Juneberry isn’t your traditional hummingbird plant but welcoming even so. And first to flower means first to fruit — nourishment for many nesting songbirds. (Photo credit Hans. Thank you, Pixabay)

Juneberry (Amelanchier spp., with more  common names than you can shake a stick at) is also an early bloomer that draws hummingbirds, bees, and butterflies. When its fruits ripen in early summer, robins, waxwings, cardinals, vireos, tanagers, and grosbeaks make a point of stopping by for a meal. You might too — the subtle flavor, shape, and color are reminiscent of blueberries. Grows well in full sun or part shade; adapts to wet or dry soils — but note soil must be acidic.

And then — raise your hand if you’ve seen our native witch hazel. This late bloomer is (metaphorically, that is) the golden chrysanthemum of the woods, daring to blossom when other trees have tucked in for a long winter’s nap. How to describe its flowers? Ribbonlike. Spidery. Kinky. Confetti-like — these all serve for a tree that’s the only show in town. But … if pollinators have tucked in too, how to play the pollination game? Turns out a native moth, the sallows, comes out on chilly nights — shivering its flight muscles and raising its body temperature upward of 50 degrees, then flying off search of food. And during a warm spell, bees will sup here too. Yes, this tree benefits birds and wildlife too, but more on that another time.

Witch hazel makes a lovely understory tree. Prefers part shade and moist but well-drained soil.

Common to all? They fit neatly under power lines.

And now a plug for IPM: it’s easy to talk about the birds and bees. Yet so many critters are on our side. Understandably we shudder when wasps and flies come to mind. But consider the scads of wasp and fly species that are on our side. Hey, plenty of wasps don’t even have stingers; they care only to lay their eggs within pest insects. Flies? Ever heard of flower flies? They do what their names suggests, while their larvae prey on aphids and thrips. And there’s scores more good guys in the family they belong to.

You can find plenty of detailed info here: Finding Alternatives to Invasive Ornamental Plants in New York. And know that we’re hosting a statewide IPM conference on invasive species and what to do about them on July 13. Save the date!

March 23, 2017
by Mary M. Woodsen
Comments Off on IPM celebrates Earth Day — the countdown to April 22

IPM celebrates Earth Day — the countdown to April 22

By most measures it’s spring in the northern hemisphere. Technicalities count: regardless if you live in snowy Labrador City (pop. 9354; high of 15ºF) or greater Miami, Florida (pop. ~5.5 million and summery 76ºF), the vernal equinox marked the official start to spring.

Whether or not the weather concurs with your expectations, of course, depends on your point of view. (Here in New York, opinions are mixed.)

This Federally-endangered dragonfly is an indicator species — and indicates a healthy ecosystem. (Courtesy Xerces Society)

A month and two days later, scores of countries worldwide on six continents will celebrate Earth Day.

Issued in 2005: Even a tiny stamp can raise awareness of dwindling resources and the importance of living in harmony with nature. (Courtesy designer Chen Shaohua)

Our question to you — what does Earth Day mean for our homes and forests, our farms, lakes, and rivers? And how does IPM help?

Join the conversation via photos, Facebook, tweets — and ThinkIPM. After all, April 22 is just around the corner. Got good stories? Get in touch with Joellen Lampman at jkz6@cornell.edu.

November 29, 2016
by Mary M. Woodsen
Comments Off on Nature’s Herbicides and Lessons from Black Walnut Trees

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.

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. Are they potential herbicides? Could be.

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 is acquiring a nasty reputation of its own.

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.]

Want to know more about shrubs and flowers that don’t mind walnut trees? Cornell Cooperative Extension is here to help.

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.

1

  1. extension.iastate.edu/news/2005/jul/070701; this site also lists some compatible and incompatible plants.
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