January 2021: Taking a Close Look at 2020

Magnifying Glass2021 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 processed a whopping 2381 samples, up 58% from 2019 and an all-time record for my tenure at the PDDC.  Samples came from 69 of Wisconsin’s 72 counties, as well as 21 additional states (AZ, CA, CO, FL, GA, ID, IL, IA, ME, MD, MI, MN, MO, NV, NM, NY, ND, OH, SD, TN and WA) and three foreign countries (Canada, New Zealand and the United Kingdom).  Much of the increase in sample numbers resulted from the clinic formalizing and substantially promoting digital diagnostics for the first time.  This was necessitated by COVID-19, which limited clinic staffing (specifically student hourly help) and curtailed the clinic’s capacity to process physical samples.  In addition, having several wet seasons in a row prior to 2020, as well as a wet early 2020 season, helped promote a wide range of plant diseases.  People, sequestered at home for much of the year, seemed to take notice of and were curious about the diseases in their gardens and landscapes and as a consequence asked for more help with identifying the problems they observed.  No matter what the cause of the increase in sample numbers, I was certainly kept busy (and out of mischief) for the year.

In 2020, as in previous years, the PDDC expanded its molecular (i.e., DNA-based) diagnostic offerings.  One disease of note that was detected this year using molecular diagnostics was Potato mop top virus (a first report for Wisconsin)This virus is transmitted by the organism (a type of slime mold) that causes powdery scab.  As always, whenever I discuss the PDDC’s molecular efforts, I have to give a shout out to Sue Lueloff, the PDDC’s Assistant Diagnostician.  Without Sue, molecular diagnostics at the PDDC would not exist.  As in 2019, Sue not only tested routine clinic samples but also worked with the Wisconsin Department of Natural Resources (WI DNR) to test tree samples from around the state for phytoplasmas.

In other 2020 diagnostic highlights, Ralstonia wilt reared its ugly head once again in the US with an initial detection in Michigan.  The last occurrence of this disease in the US was in 2004.  The pathogen that causes Ralstonia wilt (Ralstonia solanacearum race 3, biovar 2) was introduced on contaminated geranium cuttings brought into the US from Guatemala and is of concern because of its potential to spread and cause severe disease on potatoes.  In fact, this bacterium is so destructive that the US government has listed it as a select agent, with potential to be weaponized by terrorists and used against US agriculture.  In 2020, potentially contaminated geranium cuttings were shipped to 650+ greenhouses in 44 states, with 19 greenhouses in Wisconsin involved.  Luckily there were no positive detections the disease in Wisconsin greenhouses.  My involvement with testing for Ralstonia wilt came in the latter half of 2020 through collaborative work with Dr. Caitilyn Allen, the UW-Madison’s world expert on Ralstonia wilt.  She was contacted by the geranium producer in Guatemala (through USDA APHIS) who was involved in the 2020 outbreak, to test current stock (for 2021 geranium production) for Ralstonia solanacearum race 3, biovar 2 contamination.  Dr. Allen’s group had insufficient staffing/resources to process the 1500 samples requested and ended up partnering with the PDDC to use the clinic’s Maxwell automated nucleic acid extraction system.  Using this equipment allowed Dr. Allen’s group to quickly obtain DNA samples from the plants that were subsequently tested for the bacterium.  Fortunately, all of the materials tested negative.

Other PDDC outreach activities were somewhat curtailed due to COVID-19.  I did end up giving 70 talks/presentations/workshops in at least 16 Wisconsin counties.  Many of these presentations were provided via Zoom with participants coming from multiple counties and sometimes the entire state.  My biggest outreach event in 2020 was Wisconsin Public Television’s Garden and Landscape Expo.  I spent three days at the event, gave three talks and helped answer questions with Lisa Johnson at two Q&A sessions (one hosted by WPR’s Larry Meiller).  I had a steady stream of visitors to the PDDC booth (newly redesigned and rebranded given Extension’s merger with the UW-Madison) and talked with and answered questions for visitors the entire time.  I distributed 4,023 University of Wisconsin Garden Facts fact sheets, brochures and other informational materials at the event.  Across all outreach programs in 2019, I interacted with almost 223,737 people (interestingly just a slight decrease from 2019).  As always, a big thanks goes out to Larry Meiller for having me on his radio show with its awesome listenership.

And finally, I can’t emphasize enough that the accomplishments of the PDDC are not a solo effort.  I have amazing help, including Sue Lueloff (molecular diagnostician extraordinaire mentioned above) Ann Joy (data entry expert who keeps federal funds flowing from the National Plant Diagnostics Network), Dixie Lang (IT support wizard who makes the PDDC website look beautiful and keeps the PDDC database running and up to snuff), Laurie Ballentine of the Russell Labs Hub staff (who never says no and happily prints, folds and otherwise produces all of the written handouts I use for my outreach efforts), and Alex Mikus (an undergraduate here at the UW-Madison who was able to help process samples in the clinic prior to the onset of COVID-19).

2020 is over – Phew!  Let’s see what 2021 has in store!

For addition information on the PDDC and its activities, check out the PDDC website, follow the clinic on Twitter or Facebook (@UWPDDC) or contact the clinic at pddc@wisc.edu.