December 2023: 2023 in Review

Review IconIt’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 new outreach projects that were (at least to me) incredibly exciting.  Here’s a rundown of the highs and lows in the clinic for the year. 

Plant disease diagnostics

Diagnosing a Plant Disease at the Microscope
Diagnosing a Plant Disease at the Microscope

2023 was, quite frankly, a horrible year in terms of sample submissions.  I completed 1005 samples (a combination of physical and digital samples) during 2023, the lowest number ever during my tenure as director of the PDDC.  I received samples from 60 of Wisconsin’s 72 counties, as well as from six additional states in the US.  Most of the samples were ornamentals (i.e., trees, shrubs, herbaceous plants), but there were a fair number of vegetable, fruit, and field and forage crop samples as well.  I’d like to give a big shout out to Dante Tauscheck, the new molecular diagnostician at the PDDC, who helped with the processing of many of these samples. 

In large part, the low sample number in 2023 was due to our extremely dry weather during the growing season.  Plant disease-causing organisms (particularly fungi) are more active in wetter weather, and we just didn’t have much rain throughout Wisconsin in 2023.  Diseases/disorders that did make a big splash in 2023 included fire blight, powdery mildew, and chlorosis.  The uptick of all of these was likely influenced by our dry weather.  Bees move the fire blight bacterium from tree to tree, and these insects tend to be more active in dry weather.  Powdery mildew fungi are known to prefer dry (i.e., no rain) but humid conditions, and that’s exactly the sort of weather we had this past summer.  And finally, lack of soil moisture likely inhibited uptake of iron and manganese by plants, thus exacerbating the chlorosis problems that we see every year throughout much of the state due to high soil pH.    


PDDC Booth at Garden Expo 2023
PDDC Booth at Garden Expo 2023

I notched 64 outreach presentations/talks during the year.  Three of those talks occurred at WPT’s Garden and Landscape Expo.  2023 marked my return to that event for the first time since the COVID pandemic started in 2020.  At Garden Expo, in addition to providing talks, I sponsored the PDDC booth, where I answered questions pretty much non-stop and distributed over 4000 UW Plant Disease Facts.  I also teamed up with Larry Meiller of WPR’s Garden Talk and Lisa Johnson of Extension Dane County to do a Q & A session.  It was a great three days.  For additional details on my experiences at the 2023 Garden Expo, check out my February web article.  

In 2023, I also debuted my PDDC Plant Disease Talks series.  I provided talks once a month on a wide range of plant disease topics and had 1465 participants over the course of the year.  While targeted toward WI residents, I ended up having participants from across the US (New York to Oregon, Minnesota to Arizona).  The talks provided general education for the public, as well as continuing education units (CEUs) to help professional arborists and Master Gardeners maintain their certifications.  I have to give a shout out to Ted Geibel and Lisa Johnson for helping behind the (Zoom) scenes to help make these talks a success.  The talks were popular enough that I will be continuing the series in 2024

Across all 64 of my presentations, including three visits to Garden Talk with Larry Meiller/The Larry Meiller Show, I helped over 210,000 people learn about plant diseases over the course of 2023. 

Online written resources

Sample Plant Disease Medallions
Sample Plant Disease Medallions

Via the PDDC website, I provided weekly updates of my clinic diagnoses (the Wisconsin Disease Almanac).  In addition, I wrote 13 web articles during the course of the year.  My favorite was probably 25 Years. . . 25 Cool Diseases, commemorating my 25th anniversary (July 1) as director of the PDDC.  Also housed on the PDDC website were the 130 titles in the UW Plant Disease Facts series.  A new twist for the fact sheets in 2023 was the debut of the Fact Sheet Medallions project.  For each fact sheet, I wrote a quiz and created a decorative electronic medallion.  You can now read a fact sheet, take the corresponding quiz, and once you get 100% on the quiz, you earn the corresponding medallion (automatically delivered to you via email).  So far, participants have taken over 1700 quizzes and earned over 450 medallions.  I know of one person who has collected all 130.  Earning medallions is not only fun, but it also qualifies as CEUs for Master Gardeners.  I have to give a special thank you to Dixie Lang, IT wizard extraordinaire, who helps maintain my clinic website and also figured out how to create the online quizzes and automation of medallion delivery that made the medallion project possible. 

The book! 

Limerickettsia: A Plant Pathologist's Book of Verse
Limerickettsia: A Plant Pathologist’s Book of Verse

I was so excited to publish my first book in 2023.  Titled Limerickettsia:  A Plant Pathologist’s Book of Verse, it contains 52 plant disease-related limericks with supplemental prose discussions of the diseases, photos, and original artwork.  I debuted the book at Garden Expo and have been selling the book as a fundraiser for the clinic since then.  Larry Meiller was kind enough to feature my book on his radio show (thanks Jill Nadeau for doing the interview!), and that’s helped with sales.  The book will never be a New York Times Bestseller (I’ve sold just over 160 copies thus far), but that was never the point.  My goal was to create a fun, alternate way for people (particularly a younger demographic) to learn about plant diseases.  I think I’ve accomplished that goal. 

Other crazy outreach

Building Block Blossom End Rot
Building Block Blossom End Rot

Another of my projects that came to partial fruition in 2023 was the plant disease building block kits that I started working on during the COVID pandemic.  I completed the blossom end rot kit this year, which includes LEGO pieces to construct diseased and healthy tomato fruits, instructions manuals, adult- and kid-oriented fact sheets, and a word search game.  The graduate student outreach group (What’s Eating My Plants or WEMP) in my department at the UW-Madison debuted the kits at the Monona Public Library in December.  I am also working with Extension 4H educators to provide kits to each county in Wisconsin in 2024.  I’m working on other kits as well (e.g., powdery mildew, downy mildew of grape, apple scab, silver leaf, Armillaria root disease, and common smut of corn) and that involves using 3-D printing to generate the parts that I need.  Hopefully, physical mock ups of these kits will be available sometime in 2024

Want to know more about the PDDC? 

All in all, 2023 was a great year at the PDDC.  As we get into 2024, and I develop new PDDC resources, I will announce their availability via Twitter (@UWPDDC) and Facebook (@UWPDDC), or via my clinic listserv, UWPDDCLearn (email me to subscribe to this).  In addition, you can always contact me by phone at (608) 262-2863 or email at

Happy New Year!