Issue 18, October 22, 2012

A Review of the 2012 Season at the University of Illinois Plant Clinic

The University of Illinois is now open year-round, but we are starting to reflect upon the 2012 growing season. Our Plant Clinic sample load has nearly tripled in the last several years. I was very thankful that we invited Travis Cleveland, U of I PSEP Specialist, to help in tree diagnosis this year during the growing season. In 2012, most of our plant samples were received from Piatt, Champaign, Effingham, Cook, Livingston, McLean, Clinton, Kankakee, and Vermilion Counties in Illinois.

When looking back to the 2011 growing season at the Plant Clinic, it was the year of spruce problems (cultural, environmental, disease, insects and spider mites). This prompted additional education outreach in 2012, such as spruce diagnostic workshops and the recent completion of a Spruce Problem (Cultural and Pests) Fact Sheet, which will be available soon.

The 2012 growing season consisted of a late frost, DROUGHT or DECLINE, and oak problems. Many in Illinois requested testing for diseases such as oak wilt, bacterial leaf scorch, and Burr oak blight (BOB). In fact, we had our first confirmation of burr oak blight (BOB) at the U of I Plant Clinic in 2012. I will quickly add that another unique disease find, in 2012, was Spruce Needle Rust (Chrysomyxa spp.).

Now, when looking at our U of I Plant Clinic fruit and veggie samples, I would say that 2012 growing season consisted of abiotic issues. Some examples that come to mind are sunscald of pepper as well as sunscald, fruit cracks, blossom end rot, catface, or zippering of tomato.

The most common disease of 2012 was Bacterial Blight or Blast of ornamental pear (Pseudomonas syringe) . We received questions about this disease throughout the season!

Some of the more challenging plant samples at the U of I Plant Clinic, for me personally, in 2012 was a palm tree problem. I was very fortunate to have received help from University of Florida– IFAS, Fort Lauderdale Research and Education Center experts such as Monica L. Elliott, Ph.D. and Timothy Broschat, Ph.D. I will never forget how Dr. Elliott told me, an Illinois farm girl, not to worry, "a palm tree is just like a corn plant on steroids." I also struggled with an African violet sample early in the season. This plant sample is an example of a problem in which I was not able to pinpoint an exact diagnosis without further information--which drives me crazy. My most involved and complex plant sample of 2012 goes to an "out-of-state" sample, which consisted of declining oaks. All I will say is that most of our U of I Plant Clinic diagnosis reports consist of one page and this particular plant sample diagnosis report consisted of seven pages.

In 2012, we were constantly on the "look out" for a new disease called Boxwood Blight (Cylindrocladium pseudonaviculatum). Luckily, we have not confirmed this devastating boxwood disease in Illinois. But, we did have a higher sample load of boxwoods this year, and diagnosed many other environmental, disease, and insect issues such as: Macrophoma leaf spot, Verticillium wilt, Volutella blight, Fusarium blight, boxwood leafminer, cold damage, and winter injury.

Downy Mildew of impatiens, another devastating disease, unfortunately did make a return to Illinois in 2012 and may be here to stay.

My favorite as well as problematic sample of 2012 arrived on my birthday! This plant sample was that of sweet basil. This tricky sample had cultural, environmental, viral, and insect issues! A sample like this is a dream for a Plant Clinic diagnostician, but a nightmare for a grower!

To conclude, I would like to thank all the U of I Plant Clinic team, which includes staff, students, volunteers, and U of I Specialists for helping to diagnose or identify the many plant samples received at the U of I Plant Clinic.

I hope that you will allow the U of I Plant Clinic to help you with your plant problems in 2013. (Stephanie Porter)

Stephanie Porter

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