Index of Monthly Columns

July: Cool Fungal Friends for a Hot and Muggy July

July 21, 2019

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

June: June is Bustin’ Out All Over (With Plant Health Problems)

June 7, 2019

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)

May: Heinous Hitchhikers – Purchased Plants as Pathogen Providers

May 10, 2019

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

April: To Prune, or Not to Prune, That is the Question.

April 4, 2019

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.

March: Viral Villains – Gruesome Guests for Indoor Gardeners and Greenhouse Growers

March 4, 2019

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

February: Wacky Wisconsin Winter Weather

February 6, 2019

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

January: 2018 in Review

December 31, 2018

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

December: Ho! Ho! Ho! A Plant Health Horror for the Holidays!

December 11, 2018

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!

November: Thank Heaven for New Plant Diseases

November 12, 2018

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: Dr. Death’s Halloween

October 4, 2018

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

September: Water, Water, Neverwhere

August 26, 2018

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

August: Free Plant Disease Testing Through the PDDC

August 10, 2018

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: 20 Years in the Life of a Plant Disease Diagnostician

July 2, 2018

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: Stormy Weather Ahead – Pathogens on the Wind

May 30, 2018

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 soybean … Continue reading June: Stormy Weather Ahead – Pathogens on the Wind

May: Rattling the Cage for Tobacco Rattle Virus

April 30, 2018

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

April: April Showers Bring…Plant Diseases (Yay!)

March 28, 2018

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!)

March: The Irish – Good Luck in Life, Bad Luck in Plants

February 26, 2018

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

February: The Facts Ma’am, Just the (UW Garden) Facts

January 29, 2018

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

January: 2017 in Review

December 30, 2017

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

December: ‘Tis the Season. . .

December 1, 2017

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. . .

November: A Plant Pathology Thanksgiving

October 31, 2017

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

October: Fall House Cleaning for the Garden

September 29, 2017

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

September: Off to the Races: The Vascular Wilt Triple Crown

August 28, 2017

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

August: Late Blight Arrives in Wisconsin

July 30, 2017

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

July: Rust – It’s Not Just for Iron Anymore

July 1, 2017

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

June: Foliar Diseases of Trees and Shrubs

May 31, 2017

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

May: Seven Tips for a Successful Vegetable Garden

May 1, 2017

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

April: Winter Injury

April 1, 2017

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

March: Seed Starting and Damping-Off

March 1, 2017

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

February: the PDDC Brings Education to You

January 25, 2017

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: Pruning in the New Year

December 28, 2016

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

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