Pests & diseases Ideas, Tips & Guides

If this sounds familiar, maybe you thought it was “your fault.” Chances are it was basil downy mildew, a devastating disease that in 2014 was reported to thwart backyard and commercial growers alike in at least 35 states plus the District of Columbia—up from 20 plus D.C. in 2013.For farmers, a once-easy, profitable cash crop is challenged; for gardeners, a beloved ingredient elusive. Is there a resistant variety, or a cultural trick to outsmarting the destructive pathogen?University researchers are collaborating in a

WHO AMONG US doesn’t have at least one Urgent Garden Question? This month on my public radio show and podcast, Ken Druse and I answered a diverse list:

Squash pests and diseases—from squash bugs, vine borers and cucumber beetles, to powdery and downy mildews and bacterial wilts—can make it all sound like just too much. But as a seed farmer, High Mowing Organic Seeds founder Stearns has to harvest lots of extra-ripe fruit to get his hidden-inside crop. He gets to the finish line by working to avoid any preventable setbacks, first and foremost, always keeping in mind the three key things about being a cucurbit:You love heat. You’re thirsty (but your shallow root system means you depend on the immediate area for water resources). You love to eat. Oh, and the aforementioned “issues” love you—some more or less depending on species and varie

Brad Herrick is Arboretum Ecologist and Research Program Manager at the University of Wisconsin-Madison Arboretum, where the staff first noticed the destructive handiwork of Asian jumping worms in 2013. He’s been studying them ever since. Though our understanding of these organisms is in the very early stages, we talked about their biology, their impact, and what control tactics are being explored by scientists seeking a solution. (Photo of Brad, below, by Eric Hamilton, UW Communications.)Update: In 2019, a year after this introductory interview, I got updates from Brad on research into the impact of heat on the embryo-filled cocoons that contain next year’s worms-to-be–that may in time help lead to answers in some situations. That newer story includes corrective tactics you can try to reduce the p

SUDDEN OAK DEATH. Emerald ash borer. Asian longhorned beetle. Woolly adelgid. I could go on naming the imported forest pests and pathogens–meaning organisms that not native, and have arrived from elsewhere–that are plaguing the trees in our forests, on our city streets, and in our home landscapes.

Adam, a graduate of the prestigious Longwood Gardens Professional Gardener Training Program, joined the staff at Swarthmore College’s arboretum in 2012. The rose garden he’s responsible for was first designed in 1956, then recently renovated to be more sustainable. In a recent chat, Adam shared tips for organic rose care today, both cultural techniques like proper spacing and using fish hydrolysate as a feed and disease-preventive, and also advice on selecting more resistant varieties. We even talked about the dreaded rose rosette disease that has been on the rise in recent years.If you’re near Swarthmore in late May and early June, treat yourself to a rose-garden tour, or just listen along as we get a virtual visit with the resident expert. Read along as you listen to the May 22, 2107 edition of my public-radio

Read along as you listen to the July 2, 2018 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here).You can also browse all the past Q&A’s with Ken Druse at this link, or visit him at his website.urgent garden questions, with ken druseQ. Hello, Ken.A. I was going to complain.Q. Oh. [Laughter.]

I’ve rounded up some of the best to tackle in the monthly Q&A segment with help from my friend Ken Druse. Ken, an award-winning garden photographer and author of more books than I can count, including “The New Shade Garden” and “Making More Plants,” produced his own “Real Dirt” podcast for 10 years, all available on KenDruse dot com (and still available on iTunes, too).Read along as you listen to the March 6, 2107 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here). This is the second segment of the March Q&A program—find the first

Westwood (below, right, in the lab) directs the Global Tree Conservation Program at the arboretum, which strives to save threatened trees from extinction through collaborations with botanical gardens and universities, and others in China, Europe, and Mexico, as well as throughout the U.S. She has a particular interest in oaks—including a number of American species in trouble—which we also talked about.Read along as you listen to the Nov. 6, 2017 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here).emerald ash borer and threatened oaks,with morton’s dr. murphy westwoodQ. Before we get started on trees in trouble, I believe I read that in 2015, the Morton Arboretum had its first millionth annual visitor tally. Is that correct?A. That’s rig

Its story – how it got here, and what it’s doing and what is being done about it — is also the story of the unwelcome arrival of other invasive exotic organisms that have come to our shores unexpectedly, and found no natural predators or other mechanisms to keep them in check.I got a 101 on the beetle from Lisa Tewksbury, manager of the University of Rhode Island’s Biological Control Lab in Kingston, where she coordinates research on the lily leaf beetle among other invasives. Learn what’s being done by scientists seeking solutions other than chem

I hear from a lot of you who have encountered rose rosette disease not on some weed as I did, but on your prized rose bushes. I invited research scientist Christina King of Star Roses and Plants—known for more than a century for many favorite garden plants, including the most popular roses today, the Knockout series—to explain what this disease is all about, how to ID it and respond to it, and what promise lies ahead for fighting it longterm.Read along as you listen to the June 18, 2018 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here).rose rosette disease with christina kingQ. As background, Christina, can you tell us a little bit about Star Roses and Plants, an

Ken is a longtime garden author and photographer, with many books to his credit including “The New Shade Garden” and “Natural Companions” and “Making More Plants.” He can be found at KenDruse dot com.Read along as you listen to the Oct. 29, 2018 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here).the october q&a with ken druseQ. Uh-oh. I can hear in y

Mostly nothing, except perhaps on the most vulnerable landscape plants—a young ornamental tree, perhaps, that might have trouble bouncing back if it suffered total defoliation.The signature bags, or webbing, of caterpillars of Hyphantria cunea—a native moth species—started showing up extra-early, too, at the start of July in 2018 instead of more like August. And now? Everywhere—even on some large-scale herbaceous plants, like my Petasites hybridus (leaf, top of p

Though this is not new information, it apparently bears repeating. I hear from readers whenever I mention animal control–even of deer–who share the “tip” that they’ve discovered mothballs, reporting that they have spread them in a vole-besieged bed, or along their deer-pressured property line, or even in a stone wall, perhaps, to deter snakes.No!Any use not specifically listed on the package violates Federal law, and can also harm you, your pets, or animals in the environment, and can contaminate soil and water, according to the National Pesticide Information Center at Oregon State. Moth balls do not belong in your garden (nor in your attic, car, or crawl space).Moth balls (and flakes) contain either napthalene or paradichlorobenzene. I frankl

Dr. David Shetlar (below left) is a professor of urban landscape entomology at Ohio State. With Dr. Whitney Cranshaw of Colorado State (below right), author of the original 2004 edition of “Garden Insects,” he created the second volume, and joined me to explain who’s in the updated version and why, and how we can get to know them better.Plus: Enter to win a copy of the new “Garden Insects of North America” by commenting in the box at the very bottom of the page.garden insects, with dr. david shetlarQ. What an undertaking this must have been. How long was this collaboration?A. Well, it was kind of interesting, Whitney and

Don’t worry: There won’t be a quiz at the end, where instead you can also share any tomato wisdoms of your own for our collective benefit.my 16 bits of tomato wisdom1. Start with a homegrown seedling (grow it like this) or a locally raised one—not a big-box-store seedling that may have been shipped in from warmer zones, where more tomato diseases are endemic and overwinter. (That logic isn’t tomato-specific; I buy local seedlings or g

Longtime friend and fellow garden writer Ken was just back from a garden-filled lecture trip across the nation, with stops at Minnesota Landscape Arboretum and in Northern California when we spoke. That’s an exceptional private garden in Piedmont, above, that he visited.Read along as you listen to the July 15, 2019 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on iTunes or Spotify or Stitcher (and browse my archive of podcasts here).q&a with ken druse: ken’s recent garden travelsMargaret Roach: Hi, Ken.

In her new book, “Plant Partners,” Jessica Walliser looks at the scientific evidence and shares pairings that can help us minimize weeds or improve soil or attract needed pollinators or other beneficial insects.Jessica is a horticulturist and self-described devoted bug lover who gardens near Pittsburgh. She’s the author of the earlier books “Attracting Beneficial Bugs to your Garden,” and “Good Bug, Bad

Are you facing any tomato troubles about now? Well, there is help to be had, in this updated interview from Dr. Meg McGrath, a longtime vegetable pathologist for Cornell University. Though people often lump everything into “late blight,” it often isn’t actually that disease at all, and it’s critical to know just what you are up against.Meg knows from tomato diseases—both as a passionate backyard gardener and as a scientist, headquartered at Cornell’s Long Island Horticultural Research & Extension Center in Riverhead, New York.Data and photos from Dr. Meg McGrath’s laboratory research, along with findings from expert colle

“I often consider ignorance the most serious pest of plants,” said J.C, as he is known, who has worked at Clemson University since 2007 and is an associate professor, running its Turf and Ornamentals Entomology research and extension program.J.C. also writes the “PestTalks” newsletter that’s part of the suite of magazines and e-newsletters from Ball Publishing, gear

This phenomenon should not be confused with browning at the tips or overall yellowing or browning that can happen at other times—such as from winter desiccation; from the effects of roadside salts; from pests and diseases (including diplodia tip blight in some pines, or phomopsis tip blight in spruce and non-resistant junipers, or similar looking kabatina in junipers); or from drought. (See what road-salt damage and winterburn look like by comparison inthese photos.)The browning I noticed in late July on my Eastern red cedar in the front yard (Juniperus virginiana) is suddenly showing up as gold or rusty-brown or a progression from one to the other on many other conifer species. The Eastern white pines (Pinus strobus), above, with their long needles, are always the most dramatic, turning what looks

To find out what scientists know so far, I called researcher Brad Herrick of University of Wisconsin-Madison, who gave us a 101 last year on these destructive worms, and has since published some new insights–specifically about the impact of heat on the embryo-filled cocoons that contain next year’s worms-to-be–that may in time help lead to answers in some situations.Brad is Arboretum Ecologist and Research Program Manager at the University of Wisconsin-Madison Arboretum, where the staff first noticed the destructive effects of Asian jumping worms in 2013. He’s been studying them ever since.Learn how to diagnose the presence of Asian jumping worms; what corrective tacti

Brad has held top horticultural positions at the Cary Institute of Ecosystem Studies in Millbrook, New York, at the New York Botanical Garden, and on a private estate. He’s currently a trustee at Innisfree Garden in Millbrook, where he’ll give a virtual talk on Wednesday afternoon, February 23, on effective solutions for dealing with deer.Read along as you listen to the February 21, 2022 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on Apple Podcasts (iTunes) or Spotify or Stitcher (and browse my archive of podcasts here). (Photo of white-tailed doe and fawn grazing, above, by Raul654 from Wikimedia.)deterring deer in the garden, with brad r

In our subsequent series of conversations, I learned a lot about these high-concentration vinegars, and most of all about reading all product labels to be a smarter, safer consumer–whether the products are natural, organic, or synthetic.My guest Noelle Orloff is the Weed and Invasive Plant Identification Diagnostician at Montana State’s Schutter Diagnostic Lab, where she identifies plants submitted by growers, ranchers and homeowners, and provides management recommendations if needed. She’s also a passionate home gardener, and I’m so glad to continue our conversa

Besides being an arboretum and public garden, The Morton is a world-class 1,700-acre research center, conservation and education organization, and it’s preparing to mark its centennial in 2022.Last year, 17,000 questions arrived by phone, email, or in person at the plant clinic, questions representing consumers from 48 states. Julie is a former landscape designer who has managed the arboretum’s free plant clinic for three years, after volunteering there for five years before that.

Things like how we’ve both shifted our handling of fallen leaves to support the environment, or how Joe’s growing more in straw bales and grow bags to rest his raised-bed soil and allow for crop rotations. How we’re both investigating what really works instead of peat moss, a non-renewable resource, as a medium for seed-starting. And much more. Joe Lamp’l is the longtime creator and host of the public-television program “Growing A Greener World” and also of the “Joe Gardener Podcast”. As if he needed more to do, in recent years, he’s created something else, the Joe Gardener Online Gardening Academy, a curriculum of virtual courses on topics from seeds to tomato, pests and weeds, to soil science and lots more.Read along as you listen to the December 20, 2021 edition of my public-radio show and podcast using the player below. You can subscribe t

It’s a story of going the distance to see those old varieties into the future in the age of climate change, and of what goes into making a successful forward-looking orchard—from smart watering methods to native underplantings and more.Mark Richardson, New England Botanic Garden’s Director of Horticulture, oversaw the recent apple orchard restoration project there, and he talked to me about what imperiled the historic collection, what it took to save them, and lessons learned that ca

Craig LeHoullier gardens and grows tomatoes in Hendersonville, North Carolina, the last couple of years after many years in Raleigh before that. He’s a proponent of the straw-bale gardening method, which he also wrote a book about. He’s an avid canner of his fresh produce and teaches an online Epic Tomatoes course with his friend and mine, Joe Lamp’l.He shared his key strategies for tomato success, and explained the different tomato troubles you might be facing and what’s behind them. And learn the provenance of ‘Cherokee Purple,’ the beloved purple heirloom that Craig named, and was responsible for nudging into commerce (for which we all thank him). (Photo of Craig below by Shoe Heel Factory from Craig’s book. Tomatoes top of page by Joe Lamp’l)Plus: Enter to win a copy of his book and some tomato see