Earlier this year, one of my colleagues called me “giddy” as I was happily expounding about all of the diseases that I was seeing this year due to our wet weather. The pinnacle of my euphoria came this month when I received a sample of one of my all-time favorite diseases, zonate leaf spot. This … Continue reading August 2024: Brian’s Bucket List Bonanza
In last month’s web article, I talked about the myriad of fruit diseases that I’ve been seeing at the clinic. This month, I thought I’d provide a summary of the vegetable diseases that I’ve been seeing. Many of the vegetable samples that I’ve received have been from commercial growers, but diseases don’t discriminate and can … Continue reading July 2024: Villainous Vegetable Violations
The 2024 field season is in full swing, and samples have been coming into the clinic at a breakneck pace. As I think about the samples that have been submitted thus far, I’m struck by how may fruit samples I’ve looked at. Here’s a summary of the fruit diseases I’ve been seeing. Apple scab Wow! … Continue reading June 2024: Fruitful Plant Diseases
While 2023 was excessively hot and dry, Wisconsin’s spring 2024 weather has been particularly wet. That wet weather has come in the form of regular rounds of severe weather. The third week in May saw a particularly violent set of storms move through the state with heavy rains, high winds (including tornadoes), and hail. With … Continue reading May 2024: Wisconsin’s Wild Weather Woes
Our early warm weather has me chomping at the bit to visit local greenhouses to spend money on my favorite annuals and perennials. Greenhouse growers do their best to produce plants that are healthy and vigorous, but even with the best of care, plants can sometimes end up with unintended disease issues. As consumers, we … Continue reading April 2024: Dodging Plant Disease Bullets at the Greenhouse
I’ve been pretty amazed by the recent temperatures in Wisconsin. Here in Madison, we hit 70°F in late February. There have been some colder days this winter, but in general temperatures have been warmer than I remember, particularly compared to what I recall from when I moved to Madison in the mid-1970s. The warm winter … Continue reading March 2024: Warming Wisconsin Weather
The 2024 PBS Wisconsin Garden and Landscape Expo (February 9 – 11) has come and gone. While I spent last week physically recuperating from Garden Expo (standing on a concrete floor gets rougher each year), my mind and spirit came away from the event rejuvenated and invigorated. The weather was perfect with four warm, snow-free … Continue reading February 2024: Garden Expo Afterglow
Mark your calendar! January 28, 2024 is LEGO* Day. I have been a big fan of LEGO in my personal life for a long time, and I was particularly excited when, several years ago, LEGO came out with their “Botanical Collection”. I must admit that I went a bit crazy and overindulged in purchasing (and … Continue reading January 2024: New Kits on the Block
It’s the last day of 2023 and time to look back and see what went on during the year at the Plant Disease Diagnostics Clinic (PDDC). In my mind, I see 2023 as probably the most creative year of my entire career. While I continued to perform my routine diagnostics tasks, I also initiated several … Continue reading December 2023: 2023 in Review
Years ago, I participated (with three other Extension colleagues) in a weekly Saturday morning horticulture Q&A radio show in Milwaukee, WI. One of the fun aspects of the show (other than being able to wax poetic about plant diseases on the air) was that I was allowed to select songs, snippets of which would be … Continue reading November 2023: Plant Pathology Playlist
October is National Apple Month and also host to my favorite holiday of the year, Halloween. (Does the latter really surprise you given my my moniker, Dr. Death?) So, in honor of both events, I decided that for this month’s web article, I’d talk a bit about diseases that can adversely affect apple fruits and … Continue reading October 2023: Poison Apples for the Halloween Season
September is National Organic Month, so I thought I’d use this month’s PDDC web article to explore techniques for plant disease management that fall within the philosophy of organic gardening. This philosophy tends to steer gardeners away from the use of chemicals for plant disease control. There are many disease management techniques that are appropriate … Continue reading September 2023: Plant Disease Management and Organic Gardening
This growing season has largely been a bust when it comes to plant diseases. Our dry weather has not been favorable for diseases (particularly leaf diseases) to development. On the other hand, 2023 has been a banner year for insects, and PJ Liesch, the UW insect diagnostician, has been very busy identifying insect problems. As … Continue reading August 2023: Bugging Out Over Plant Diseases
July 1 marked my 25th anniversary as director of the University of Wisconsin Plant Disease Diagnostics Clinic. In celebration of that milestone, this month’s web article highlights 25 diseases, disorders, and oddities that look like diseases, but aren’t. All of these tickle my fancy as a geeky plant pathologist. I am emphasizing diseases/disorders/oddities that can … Continue reading July 2023: 25 Years. . . 25 Cool Diseases
Mark your calendar. June 13th is National Weed Your Garden Day. It’s time to get out into your garden to remove those unwanted plants growing in amongst your prized herbaceous ornamentals and tasty vegetables. Not only will weeding make your garden look more tidy and beautiful, it will also help make your favorite garden plants … Continue reading June 2023: Weeding is Fundamental!
There was a fair amount of pomp and circumstance earlier this month surrounding the coronation of King Charles III of England. As I was reading the news articles, I began to imagine how plant diseases might fit into a coronation ceremony. I doubt that British royals would find any of the diseases that I deal … Continue reading May 2023: Jewels in the Crown
The Plant Disease Diagnostics Clinic (PDDC) typically charges a small fee for providing diagnoses of plant diseases and disorders. However, there are certain instances where the PDDC waives fees. In particular, if there are plant diseases that are new to the state and/or potentially have severe negative economic impacts to Wisconsin agriculture, the PDDC does … Continue reading April 2023: The Best Things in Life Are Free!
I absolutely loathe exercising. That said, I try to force myself to do at least some sort of cardiovascular workout every day in an attempt to fend off the weight gain that seems to come with age (and my inability to stop eating everything bad for me in sight). One thing that (sort of) makes … Continue reading March 2023: UW Plant Disease Facts Medallions – Collect Them All!!
I have spent a substantial portion of my career writing about plant diseases. When I started at the UW-Plant Disease Diagnostics Clinic in 1998, one of the first things articulated by county Extension educators was their need for short, concise, and to-the-point fact sheets on a variety of horticulture topics. This need led to the … Continue reading March 2023: Reading is Fun(gi)damental
I have just finished catching up from the 2023 PBS Garden and Landscape Expo (Friday, February 10 through Sunday, February 12). My booth displays are back in storage, and I’ve documented all of the various education materials that I provided for visitors. This was my first in-person Garden Expo post-COVID. I have to say the … Continue reading February 2023: Recovering from Garden Expo 2023
2023 has arrived, and I’m already thinking ahead to the deluge of samples that are likely to arrive at the UW Plant Disease Diagnostics Clinic (PDDC) this summer. PDDC personnel continue their efforts to balance providing high quality services to the public with keeping clinic staff and clients healthy and safe. The following are current … Continue reading January 2023: Plant Disease Diagnostics Clinic Services for 2023
‘Tis the Season to buy holiday gifts. I often have a difficult time coming up with ideas for what to buy for friends and family who seem to have everything. Similarly, I’m a frustrating person to buy for; I just have too much stuff. If you’re trying to come up with that perfect gift, and … Continue reading December 2022: A Plant Pathologist’s Holiday Shopping List
I’ve been around long enough at the PDDC (25 years next summer) that most of the diseases that I see at the clinic are old friends. Rhizosphaera needle cast, oak wilt, Verticillium wilt and many others are part of the cast of plant disease characters that I see in Wisconsin every year. It’s relatively rare … Continue reading March 2022: Checking Out the New Gym (or Flexing Your Muscles on a New Wisconsin Disease)
Here at the Plant Disease Diagnostics Clinic (PDDC), we strive to provide the best possible diagnoses of plant disease problems. PDDC staff use a range of techniques to do this including visual and microscopic examination of plant tissue, incubation of tissue in moist chambers to coax fungal pathogens to sporulate, culturing techniques to grow pathogens … Continue reading February 2022: Optimizing Your Diagnosis at the PDDC
As we start 2022, COVID-19 continues to inform how the UW Plant Disease Diagnostics Clinic (PDDC) provides services to the public. Clinic personnel continue to try to balance providing high quality services to the public with keeping clinic staff and clients healthy and safe. The following are current guidelines for submitting samples and tapping into … Continue reading January 2022: Plant Disease Diagnostics Clinic Services for 2022
I have recently received a slew of questions about wilted tomatoes in home gardens. Here are the top five reasons that tomatoes can wilt based on samples that I have received in my clinic over the years. Walnut toxicity One of the lessons that I have learned after doing plant disease diagnostics for over 20 … Continue reading July 2021: Summer Doldrums – Wilted Tomatoes in the Garden
It‘s the time of year where I am once again getting questions about apple and crabapple trees with dead branches. Often, in these situations, clients assume that their trees are suffering from fire blight. This bacterial disease has received a lot of press over the years and can be a serious problem. However, fire blight … Continue reading June 2021: Fired Up About Fire Blight
I really love this time of the year as plants emerge once again after their long winter naps. I also love the fact that I now get to start looking once again for some of my favorite plant diseases. At the top of the list at this time of the year are the rust diseases. … Continue reading May 2021: Rampant, Ravaging Rusts
I have the coolest job on the planet. Everyday, I get to help people with their plant disease problems. This may entail helping someone learn how to grow healthy, nutritious vegetables to feed their family or assisting a grieving family select the just the right tree to plant to serve as a lasting memorial for … Continue reading April 2021: Tomato in the Basement, Canary in the Coalmine
As the temperatures begin to warm and the snow melts, gardeners are chomping at the bit to be outdoors working away. Thoughts tend towards “What should I plant this year?” and “When should I plant and seed?” Those are great questions, but there are other aspects of gardening that I think are important to consider. … Continue reading March 2021: Gardening Ideas for the 2021 Growing Season
In this month’s Plant Disease Pointers, I discussed the advantages of pruning trees and shrubs in the winter to increase structural soundness and overall aesthetics. Winter is also a great time to inspect trees and shrubs for certain diseases and, where needed, prune out these problems. Diseases that can be corrected, at least in part, … Continue reading February 2021: Deep Freeze Search and Destroy
2021 has arrived and I can’t say that I’m sad to see 2020 gone. Last year was incredibly challenging for everyone due to COVID-19. I am very grateful to still have job and to be able to do the work that I love. Here’s how things shook out in 2020 at the PDDC. Clinic staff … Continue reading January 2021: Taking a Close Look at 2020
I think it’s safe to say that 2020 was a surreal year for everyone, including those of us here at the Plant Disease Diagnostics Clinic. COVID-19 fundamentally changed how the PDDC conducted business (e.g., check out my March 2020 Monthly Column for details on how the clinic handled sample submissions in 2020). As I look … Continue reading December 2020: Launching into 2021
As cold temperatures arrive in Wisconsin, many diehard plant enthusiasts are now concentrating on inside gardening activities involving their favorite houseplants. In some cases, people have been growing their houseplants outdoors for the summer and recently (or perhaps not so recently) brought them back indoors to avoid plummeting fall temperatures. In other cases, gardeners have … Continue reading November 2020: Houseplant Horrors
Autumn has arrived in Wisconsin, with days shortening and temperatures cooling. As gardeners begin putting their gardens to bed for the winter, they have been coming across what they consider alarming developments on their herbaceous ornamentals, deciduous trees and evergreens. Luckily, most of what they have been seeing is innocuous and non-life-threatening. Here is a … Continue reading October 2020: Autumn Angst
Because of the COVID-19 pandemic, I have been doing a large number of digital diagnoses this summer. While I have always felt that working with physical samples is the best way to diagnose disease issues, there has been one area where having access to photos has been of great benefit: diagnosing non-disease issues causing general … Continue reading September 2020: Perennial Planting Problems
Lilacs are one of my favorite spring-flowering shrubs. When sited properly (in full sun) and pruned/thinned regularly, they reliably produce a bounty of beautiful blooms each spring in a myriad of colors. And oh that scent! Is there really anything that smells better than the scent of lilacs in full bloom? In most years, lilacs … Continue reading August 2020: Green Grow the Lilacs – NOT!
2020 has been a banner year for rust diseases. I can’t remember a year where I have seen so many rusts on so many different plants: apple, ash, buckhorn, crabapple, elderberry, hawthorn, Jack-in-the-pulpit, juniper (including red cedar), mayapple, raspberry, spinach, spruce, violet and white pine. Rust diseases are caused by a closely related group of … Continue reading July 2020: Elderberry Whine – Rust, Rust Everywhere!
These days, digital photos of diseased plants are arriving fast and furious in the Plant Disease Diagnostics Clinic (PDDC) email inbox. While clients have been having problems with many different types of plants, I have been receiving a large number of photos of stone fruits. Ornamental and fruit-bearing varieties of cherries, plums and peaches seem … Continue reading June 2020: Cherries and Peaches and Plums, Oh My!
Most days, I really love my job. I am well-known for my love of plant disesaes and I tend to get giddy when plant samples arrive at the PDDC. There is always the possibility with each new package that I will become reacquainted with an old disease friend (e.g., cedar-apple rust) or that I will … Continue reading May 2020: Toxic Plant Disease Olympics
The impact of COVID-19 on the Plant Disease Diagnostics Clinic (PDDC) and the services that the clinic provides has continued to evolve. As of March 28, 2020, and until further notice, the PDDC is no longer accepting physical samples for diagnoses, and clinic staff members are restricted to working from home. Nonetheless, I and the … Continue reading April 2020: What Do I Have to Do to Get My Picture Took?
LAST UPDATE: June 18, 2021 Over the past week, reports of COVID-19 in Wisconsin have increased dramatically. To help keep PDDC customers and staff safe, I am making changes to the way the PDDC delivers services. Below is a list of what will change, and what will remain the same. I will … Continue reading March 2020: Plant Disease Diagnostics in the Time of COVID-19
Last month in my summary of my activities for 2019, I mentioned that I had given 111 talks/presentations/workshops during the course of the year. This month I’d like to elaborate a bit on the types of outreach presentations that I provide. Audiences Quite frankly, I’m willing to talk about plant diseases on any crop/plant other … Continue reading February 2020: Yacking It Up About Plant Diseases
Wow! It’s 2020 already and I can’t say that I’ve recovered yet from the avalanche that was 2019. Sample Processing Clinic staff processed 1506 samples, up roughly 17.5% from 2018. Samples came from 64 of Wisconsin’s 72 counties, as well as FL, IA, IL, IN, MA, ME, MI, MN, and NY. Sample numbers were … Continue reading January 2020: 2019 in Review
Over the past two weeks, I have received a number of photos of incredibly cool microorganisms that have popped up in people’s gardens or around their homes. These organisms have all turned out to be non-pathogens (i.e., they don’t cause plant diseases), but they are some of the more extraordinary organisms that I encounter in … Continue reading July: Cool Fungal Friends for a Hot and Muggy July
With the arrival of June, the plant disease floodgates have burst and the PDDC has been deluged with plant specimens with a wide range of plant health issues. Probably the most striking samples showing up at the clinic right now are those that are showing symptoms of winter/cold injury. I continue see samples from trees … Continue reading June: June is Bustin’ Out All Over (With Plant Health Problems)
As we get into May, many gardeners begin thinking about buying perennials to replace plants that have died over the winter, or annuals to fill decorative pots and hanging baskets. Being the optimist that I am (NOT), whenever I’m visiting my local nursery or garden center, I’m always evaluating plants as potential sources of plant … Continue reading May: Heinous Hitchhikers – Purchased Plants as Pathogen Providers
As warmer weather has spread through much of Wisconsin, I have talked with more and more gardeners who are chomping at the bit to get into their yards and start the 2019 gardening season. One of the activities these gardeners are contemplating is the pruning of their trees and shrubs. They often ask me whether … Continue reading April: To Prune, or Not to Prune, That is the Question.
Recently, I have seen an increase in conservatory and greenhouse-grown plants arrive at the PDDC. It’s certainly the time of year that greenhouses gear up their plant production in anticipation of spring sales (assuming that spring is going to arrive this year – I have my doubts). There are several viral diseases that I routinely … Continue reading March: Viral Villains – Gruesome Guests for Indoor Gardeners and Greenhouse Growers
After last week’s sobering, subzero weather, I began to think about all of the ways winter in Wisconsin is designed to make the life of plants, particularly woody ornamentals, difficult. Snow Snow can be a mixed blessing. I like to see a few inches of snow on the ground, because snow actually has an insulating … Continue reading February: Wacky Wisconsin Winter Weather
As the New Year rolls in, it’s time to reflect on the past year and all that happened at the PDDC. Clinic staff processed 1282 samples, down roughly 11% from 2017. These samples came from 62 of Wisconsin’s 72 counties, as well as FL, IA, ID, IL, ME, MI, MN, MO, NM and TX. While … Continue reading January: 2018 in Review
As the December holiday season nears, one of the traditions for many folks is to decorate their homes with festive greens. When selecting wreaths and garlands to using in decorating, keep in mind that you may not only be bringing pine boughs and holly into your home, but also plant pathogens. Of particular concern has … Continue reading December: Ho! Ho! Ho! A Plant Health Horror for the Holidays!
One of the traditions of the Thanksgiving season, is to contemplate the past year and express thanks for positive aspects of our lives. Thinking of this concept in the context of plant diseases, I thought that in this month’s web article, I would discuss new diseases that I saw in the clinic in 2018 that … Continue reading November: Thank Heaven for New Plant Diseases
October hosts my favorite holiday of the year, Halloween. Call me sentimental, but how can you go wrong (having a moniker like “Dr. Death”) with celebrating a holiday that caters to things that creep and crawl in the night. Most people think what I enjoy and do professionally is pretty weird and I have to … Continue reading October: Dr. Death’s Halloween
There is a certain irony of me writing an article about watering plants after Madison, WI (where I live) recently received record amounts of rainfall and, as I write this article, is experiencing flooding in many areas of the city. However, as September arrives, the psychology of many gardeners seems to be that as we … Continue reading September: Water, Water, Neverwhere
While the Plant Disease Diagnostic Clinic (PDDC) typically charges a small fee for processing plant disease samples, there are certain diseases where diagnoses are performed for free. These diseases typically fall into four categories: Diseases that have not been documented in Wisconsin, but should they be introduced could cause serious damage, and thus early detection … Continue reading August: Free Plant Disease Testing Through the PDDC
July 1, 2018 marks my 20th anniversary as director of the UW-Madison/Extension Plant Disease Diagnostics Clinic. It really seems just like yesterday that I started at the clinic. I remember being so excited about being asked to interview for the position, but terrified that I wouldn’t be hired because my diagnostic background was very limited. … Continue reading July: 20 Years in the Life of a Plant Disease Diagnostician
June 1 marks the beginning of Hurricane season in the Atlantic and while full-blown hurricanes do not reach Wisconsin, their effects (and those of other seasonal winds) can have an influence on plant diseases. Soybean rust A somewhat recent example of an apparent direct effect of a hurricane was the introduction of the Asian … Continue reading June: Stormy Weather Ahead – Pathogens on the Wind
It’s been a long winter and now temperatures have warmed to the point that spring emphemerals in my backyard are beginning to emerge and bloom. As their leaves begin to appear, I am on the lookout for symptoms of tobacco rattle caused by Tobacco rattle virus (TRV). I know I have TRV in my garden and … Continue reading May: Rattling the Cage for Tobacco Rattle Virus
It appears that spring is slowly arriving, and with the spring typically comes regular, often frequent rain showers. The upside to this moisture is that it helps thaw the ground and stimulate plants to grow. The downside however can be that this moisture provides a favorable environment for plant diseases to develop. Damping-Off If you … Continue reading April: April Showers Bring…Plant Diseases (Yay!)
As March arrives, being in part Irish by ancestry, my thoughts tend towards St. Patrick’s Day and as a plant pathologist, I imagine what havoc plant disease might cause for the holiday. Shamrocks A major symbol of St. Patrick’s Day is the shamrock. While several plants can be called shamrocks, the most common plant to … Continue reading March: The Irish – Good Luck in Life, Bad Luck in Plants
The winter months are the prime period at the PDDC when staff are able to concentrate on outreach activities that do not involve diagnosing diseases on plant specimens. One of the major outreach efforts of the PDDC has been and continues to be the University of Wisconsin (UW) Garden Facts fact sheet series. The UW … Continue reading February: The Facts Ma’am, Just the (UW Garden) Facts
The PDDC was a busy place in 2017. Clinic staff processed 1445 samples, with samples coming from every county in Wisconsin other than Lincoln, Menominee and Price Counties. The PDDC also received samples from FL, IA, IL, ME, MI, MN, MO, NY, PA, SD, TX and WA. I personally also provided digital disease diagnostics via … Continue reading January: 2017 in Review
It’s holiday time and while most folks have visions of sugar-plums dancing in their heads, my mind takes a detour to the dark side as I think of how plant pathogens can influence the holidays. Interestingly, the examples that first come to my mind are positive influences on the holiday season. Poinsettias anyone? If you … Continue reading December: ‘Tis the Season. . .
As we head into November, I’m thinking ahead to the bounty of food that will be served on Thanksgiving Day. Of course, being a plant pathologist, it’s also fun for me to think about what might go wrong (from a plant disease perspective) to prevent some of my favorite dishes from making it to the … Continue reading November: A Plant Pathology Thanksgiving
One of the easiest and most effective ways to help manage plant diseases is good fall cleanup of your yard and garden. Many common fungal and bacterial plant pathogens, particularly those that cause leaf diseases, survive Wisconsin winters in leaf litter from trees and shrubs, as well as on herbaceous plant parts that have died … Continue reading October: Fall House Cleaning for the Garden
As we move into late July and August, I typically see an increase in sample submissions for vascular wilt testing. Vascular wilts are diseases where the pathogen (typically fungal or bacterial) invades the water-conducting tissue (called the xylem) inside a plant and leads to blockage of this tissue. The blockage prevents water from moving from … Continue reading September: Off to the Races: The Vascular Wilt Triple Crown
On July 26, late blight (caused by the water mold Phytophthora infestans) was formally diagnosed in Wisconsin for the first time in 2017. The late blight sample was of infected tomato fruits from Waukesha County. Late blight attacks both potatoes and tomatoes, and unchecked the disease can rapidly kill plants. Late blight is the disease … Continue reading August: Late Blight Arrives in Wisconsin
In my June web article, I mentioned cedar-apple rust and other Gymnosporangium rusts as diseases that I expected to see a lot of this year. This has certainly been the case over the last month. What has surprised me (and I probably shouldn’t be surprised given our continuing wet weather) is the plethora of other … Continue reading July: Rust – It’s Not Just for Iron Anymore
May has been a fairly wet month in many parts of Wisconsin. When spring rains overlap with leaf emergence on broad-leafed trees and shrubs, expect leaf diseases to run rampant over the summer. Some of diseases that I have already seen or I am expecting to see this year include: Anthracnose Anthracnose refers to a … Continue reading June: Foliar Diseases of Trees and Shrubs
If you are like many vegetable gardeners, you have transplants growing in your basement under artificial lights and are chomping at the bit to get those plants out into your garden. Before you do that, here are a few things to think about to make your summer vegetable garden more successful. Finish any last minute … Continue reading May: Seven Tips for a Successful Vegetable Garden
This past winter’s weather was a roller coaster ride of seasonably cold temperatures in December and January, followed by record warm stretches in February, followed by cold temperatures again for much of March. These extreme temperature fluctuations can injury many woody landscape plants. The Most Typical Forms of Winter Weather-related Plant Injury Cold injury Cold injury … Continue reading April: Winter Injury
Preparing for Spring March is the month when many gardeners begin to think about starting vegetables and ornamental annuals from seed indoors. While seed-starting can be an economical method for producing plants for home gardening, damping-off can put a damper (no pun intended) on this fun winter gardening activity. Forms of Damping-Off Damping-off can take … Continue reading March: Seed Starting and Damping-Off
Did you know that the PDDC offers educational programs throughout the state of Wisconsin? Take a look at our stats from last year: This year is shaping up to be even busier. Talks and Workshops Brian Hudelson, the PDDC Director, designs and delivers custom, in-person presentations to groups throughout the state of Wisconsin. Target audiences include … Continue reading February: the PDDC Brings Education to You
January is the time of year to start thinking about maintenance pruning for the trees and shrubs in your yard. While there are exceptions, for many trees and shrubs, pruning during colder weather (when disease-causing organisms and insects are not active) can help minimize infections through pruning wounds. The “January Thaw” If you decide to … Continue reading January: Pruning in the New Year