In a recent study, 45 species of crop
and weed plants were screened for their susceptibility to P. capsici.
Although 22 crop species succumbed to the disease, 14 did not.
Mohammad Babadoost, plant pathologist at the U of I in the College
of Agricultural, Consumer and Environmental Sciences, believes that
rotating the 14 resistant vegetable varieties may serve to wait out
the pathogen until it is safe to once again plant pumpkins or other
crops susceptible to P. capsici.
Crop rotation is already being used by
pumpkin growers as an important component of disease management,"
said Babadoost. "Most pumpkin growers in Illinois follow at
least a short-term crop rotation. However, most growers have
experienced heavy losses when carrot, lima beans, pea, pepper, snap
bean and tomato were grown prior to pumpkin."

In order to make crop rotation a
successful solution to waiting out the pathogen, a critical question
remains to be answered: How long does the pathogen stay alive in the
soil?
"Unfortunately, we don't know how
long," Babadoost said. "Currently, I have a graduate student
investigating that. We are trying to work out the problem piece by
piece, then develop effective strategies to manage this disease.
Definitely, the study that Tian completed provided us with very
valuable information in dealing with this destructive pathogen."
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Soybean, corn and wheat, the major
crops grown in Illinois, did not become infected, and there is no
report indicating that these crops are hosts of P. capsici. The
other 11 vegetable crops that, when inoculated with P. capsici, did
not develop symptoms of the disease are basil, broccoli, cabbage,
cauliflower, celery, chive, dill, kale, kohlrabi, mustard and
parsley.
In the study the 22 vegetable crop
seedlings that became infected and developed symptoms of the disease
were beet, carrot, eggplant, green bean, lima bean, radish, snow
pea, spinach, Swiss chard, tomato, turnip, onion, pepper and a long
list of vine vegetables, including pumpkin, cantaloupe, cucumber,
gourd, honeydew melon, muskmelon, squash, watermelon and zucchini.
Babadoost said that the incidence of
fruit rot on pumpkins caused by P.capsici has dramatically increased
in Illinois, causing yield losses of up to 100 percent.
"Jack-o'-lantern pumpkin is an important crop in Illinois, and
approximately 90 percent of the commercial processing pumpkin
produced in the United States are grown in Illinois, so this is an
economic problem for the state."

Babadoost
and crop sciences graduate student Donglan Tian completed the study
published in the May 2004 issue of Plant Disease by the American
Phytopathological Society. The research was supported in part
by funds from North Central Region Sustainable Agriculture, Research
and Education; the Illinois Department of Agriculture; and Nestle
Food Inc.
[University
of Illinois news release]

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