COLUMBUS, Ohio – Ohio’s pumpkin crop is turning out to be a paradise for diseases.
Localized heavy rainfall and cooler than normal temperatures have helped spawn such diseases as downy mildew and bacterial spot.
The result, said Ohio State University plant pathologist Mac Riedel, could be a poor-yielding crop with no consistency in pumpkin size or quality.
“Overall, I think the pumpkin crop will be a light one,” said Riedel. “In the wet zone through west central Ohio I don’t think the crop will be exceptional.”
Lagging behind. Because of unfavorable weather conditions at the beginning of the growing season, pumpkins are behind in development.
Most of the crop is just now starting to “size up” and turn color, and with diseases impacting the crop during this critical stage, it will be difficult for growers to harvest a large quantity of good-sized fruit.
“The tonnage may be affected,” said Riedel. “And where normally growers would be able to get a 25 pound pumpkin, they may only get 10 or 15 pounds.”
Downy mildew. Riedel said downy mildew is one disease specialists are concerned about.
Downy mildew, which emerges under wet, cool conditions, affects crop foliage.
It is characterized by fuzzy, white to grayish patches on the underside of the leaves. The upper part of the leaves may contain pale yellow or green spots.
“This is the worst I’ve seen downy mildew in 25 years. The disease is knocking foliage off the plants and, as a result, the fruit is not going to “size up” properly,” said Riedel.
“Also, if we get really hot temperatures in September, the fruit will burn because there will be little foliage to protect the crop.”
Riedel said that once downy mildew starts, little can be done to stop its spread.
“The disease produces so many spores in such a short period of time. A few lesions can turn into a calamity very quickly,” he said.
Bacterial spot. Bacterial spot is another disease that is impacting the pumpkin crop.
The disease is characterized by small, round, white spots on the fruit that form cankers. The disease works its way to the rind, eventually rotting out the inside of the pumpkin.
“We don’t have good chemical control for this disease, but one good thing is that it tends to be variety-dependent,” said Riedel.
“Fruit with harder rinds tend to show fewer symptoms than softer-rind varieties.”
Growers have already begun harvesting the crop in some areas to capitalize on the wholesale market. Harvest will continue through mid-October.
According to the USDA, Ohio is ranked fifth in the nation in pumpkin production. Approximately 5,000 to 6,000 acres of pumpkins are grown in Ohio, generating roughly $25 million a year in revenue in local sales and exports to southern states.
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