Tag: Connecticut Agrigultural Experiment Station

Tomato Mystery–Part One

Why are many of my tomatoes ripening on a table inside instead of on the vine?

Prudens Purple In Foreground Cherokee Purple In Background 8 24 12 Thumb     Milano Plum Tomatoes 8 24 12 Thumb

These are Pruden’s Purple (foreground) and Cherokee Purple (background) on the left, and Milano Plum tomatoes on the right, in a scene I’m used to creating just before frost when all potentially viable tomatoes are brought inside to ripen. This is not a sight I want to see in August.

But … when tomato vines begin developing brown patches on leaves and stems, and continue to do so at an ever increasing rate, it’s time to take action.

JMH 8 2012 Tomato Disease 6 Thumb

Fearing dreaded tomato late blight, I took photos and collected samples of leaves and stems with brown patches. I then carefully removed the plants, cutting each stem into pieces that would fit into a trash bag. Four five-foot tall tomatoes that I nurtured from seed, and should have been in their prime, were reduced to common trash. Normally, I compost plant waste but it’s not good practice to compost diseased plant material.

I called the Connecticut Agricultural Experiment Station and reached Dr. Yonghao Li, plant pathologist in the Plant Disease Information Office. After reviewing my emailed photos Dr. Li asked to see the actual samples. He suspected some sort of blight.

JMH 8 2012 Tomato Disease 13 Thumb

I packed each tomato leaflet between dry paper towels and sealed two stacks of samples in zip-lock bags, then mailed them, express delivery, so they would get to Dr. Li before completely drying out.

Dr. Li called after inspecting the samples under microscope to report no blight; no bacterial disease of any type.  We ruled out pesticide/herbicide drift from a neighboring property, sunscald as this would not cause browning patches on stems, and soil (I used new commercial composted potting soil for each potted tomato). Dr. Li suggested some sort of virus might be the cause.

Unfortunately, he said testing for a virus is not as simple as microscopic inspection for bacterial infection. Each virus test requires an individual test kit and still may not provide definitive results. In other words, virus testing is not cost effective. I’ve compared my diseased tomatoes with photos of virus-infected tomatoes and found no match.

Dr. Li suggested my tomato problem may be seed-borne. I started this year’s plants from the same seed (from two separate seed suppliers) as last year and had the same problem at about the same time with my 2011 tomatoes. In both seasons, this and last, small brown spots began showing up on leaves at all levels of the plant, some expanded to larger size with yellowing at the outer edges while brown patches developed on some stems and at some leaf nodes. The heirloom Pruden’s Purple and Cherokee Purple tomatoes were the first to show these signs, followed by Milano Plum tomatoes. Last year the Manyel tomatoes were the last heirloom to show signs and, this year, my one Manyel plant still looks healthy.

I’m very appreciative of the assistance of Dr. Li and highly recommend other gardeners seek the advice of the Plant Disease Information Office.

I’m relieved that my tomatoes don’t have blight but I’m still at a loss to explain the disease cause. I can guarantee that next year I’ll start with fresh tomato seed, likely from  different companies.

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Boxwood Blight: A New Connecticut Worry

The Connecticut Agricultural Experiment Station (CAES) recently reported a new-to-Connecticut boxwood disease, a fungus called Cylindrocladium pseudonaviculatum. Sounds ominous, doesn’t it? Wait till you learn more.

According to facts and photos in the boxwood blight fact sheet prepared by Dr. Sharon M. Douglas, of the Department of Plant Pathology and Ecology at CAES, the disease is as ominous as it’s Latin name sounds.

Early stages of boxwood blight first appear as dark or light leaf spots or lesions, often with dark borders. The spots grow to cover more of each infected leaf causing leaves to turn brown or straw colored. Defoliation is likely to occur shortly after leaf symptoms develop.

Infected stems show dark brown to black lesions, sometimes with a diamond-shaped pattern. Lesions run from the soil line to the stem tip.

The fungus does not appear to affect boxwood roots but, as the plant sends up new growth in response to defoliation, new growth becomes infected from remnants of the fungus. Repeated regrowth and reinfection weakens and eventually kills.

Check out the disturbing photos in the boxwood blight fact sheet of all disease stages or watch this YouTube video.

Boxwood blight spreads rapidly in warm, humid conditions – think greenhouses and hoop houses. It loves temperature ranges of 64 to 77 degrees Fahrenheit (77 being optimum) but can die after seven days at 91 degrees Fahrenheit. It may also live up to five years on decomposing boxwood leaves.

Boxwood blight spores spread by wind, wind-driven rain and water splash and, since the sticky spores easily attach to clothing, boots, tools, and animals, spores can also be spread via human and animal movement.

So, what can one do? Since the disease is newly identified in Connecticut CAES recommends we

  1. Buy disease-free material from reputable nurseries and carefully inspect all plants before purchasing.
  2. Isolate newly purchased plants for at least one month and preferably for several months.
  3. Space plantings to maximize air circulation.
  4. Avoid overhead watering and working among plants when they are wet.
  5. Remove boxwood leaf debris from around plants.
  6. Become familiar with symptoms by studying images of the disease in the links above.
  7. Inspect for symptoms each week. If detected, immediately pull and remove entire plant and dispose of infected material in plastic bags. Do Not Compost.
  8. Stay in touch with CAES for the most current information on control. Of note: Boxwood blight has been common in England and other countries for years and has not been controlled by fungicides.

If you suspect boxwood blight follow these instructions for submitting samples to CAES for diagnosis.

The disease has been found in Hartford, Middlesex, Fairfield and New London counties in Connecticut. Since one of these counties is mine and I already have a fair number of boxwood planted in my deer-accessible gardens (boxwood are one of the few shrubs my local deer don’t yet eat), I’m going to watch my boxwood closely.

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