Marting looks over some of his cherry tomato
plants in his backyard in Akron, Ohio, on August
21, 2015. His plants, that usually produce an
abundant crop, have only been able to produce a
handful of tomatoes this summer.
Ohio ó It has been a tough couple of years for
gardeners in Ohio and elsewhere have struggled with
sickly tomato plants the last two summers, the
unfortunate fallout of a perfect storm of weather
conditions. And just as the fruit that managed to
survive is reaching its luscious peak, another tomato
killer is poised to strike.
late blight of tomato, an especially destructive disease
that spreads with abandon and can wipe out a whole field
of tomato plants in a matter of days. It has been
identified in one Ohio county and could spread fast and
far, said Erik Draper, an assistant professor with the
Ohio State University Extension and its director of
commercial horticulture for Geauga.
it comes in this early, this is not a good thing. We
will lose most of our tomatoes to this disease," he
late blight spreads in cool, wet conditions, exactly
what we see this time of year when nighttime
temperatures drop into the 60s and heavy dew forms, he
disease used to be easier to control, he said, but in
recent years it has run rampant. Thatís partly because
conditions have been right for the disease to spread,
but Draper believes itís also because the fungus-like
organism that causes the disease, called an oomycete,
has developed more aggressive strains.
visited a commercial growerís tomato field in Geauga
County recently and found a section in the middle with
infected plants. When he returned a week later,
"from one end of the field to the other, it was
gone. All the tomatoes were gone," he said.
signs of late blight are black or brown spots on stems.
Large spots on leaves that look water-soaked at first
and then turn brown, often with a border of light green,
wilted tissue. Fuzzy growth on underside of leaf spots.
Large, brown, firm spots on fruits.
most fungicides available for home use arenít
effective at protecting tomato plants against late
blight, because the culprit isnít a fungus, Draper
tough news for gardeners, many of whom have already been
frustrated by tomato tribulations the past couple of
year and last, cool temperatures early in the season
delayed planting and slowed early growth. So when the
usual disease-causing organisms started moving in, the
tomato plants were still young and vulnerable, Draper
explained. Adding to the problem were heavy rains, which
sometimes wounded plants and gave bacteria a way in.
Akron gardener Bill Marting has managed to harvest only
a handful of cherry tomatoes from his dozen or so
plants, and there are few clusters of tiny tomatoes
waiting to mature. Usually by early September, heís
harvesting tomatoes by the bucketful, he said.
blamed the heavy June rains, which turned his foliage
yellow. Although the plants have bounced back and heís
seeing some blossoms, heís resigned to a disappointing
was a great year for weeds and mosquitoes," he said
disease that has given many gardeners grief this year is
early blight of tomato, Draper said. Despite its name,
early blight can strike throughout the season and is
caused by a fungus, a different organism than the one
that causes late blight.
diseases called bacterial speck, bacterial spot and
bacterial canker have also been common, he said.
Septoria leaf spot, another fungal disease, has damaged
some leaves and stems.
matter whatís troubling their tomatoes, gardeners can
improve their chances for next year by cleaning up plant
debris thoroughly at the end of the season, Draper said.
That way, thereís less chance disease-causing
organisms will hang around in the soil, waiting to
re-infect plants next year.
away diseased plants rather than composting them, he
said. Most home composting piles donít get hot enough
to destroy the disease-causing organisms, especially in
watch for new plants that sprout from the seeds of
tomatoes left on the ground. Remove and destroy them,
disease-resistant tomatoes can also help. Cornell
University has a chart at