By KAREN BINDER
Illinois Correspondent

MORTON, Ill. — Here in the top-producing pumpkin state, John Ackerman listens carefully when he hears someone like Mohammad Babadoost use the phrase Phytophthora blight.

It was just 10 years ago that the disease nearly wiped out Illinois’ entire pumpkin crop, which led to a national shortage of the processed vegetable during its peak demand – the Thanksgiving and Christmas holidays.

Babadoost, a fruit and vegetable pathology specialist with the University of Illinois Extension, says conditions appear ripe now for a return of the disease unless growers are vigilant.

Illinois growers account for about 95 percent of the nation’s processed pumpkin supply, tending to nearly 25,000 acres of mostly processing pumpkins, as well as a healthy mix of ornamentals. It is a $160 million industry for Illinois.

Ackerman Farms is located in the heart of Illinois’ pumpkin growing region, in the central Illinois town of Morton. It is home to Libby’s largest pumpkin processing plant, which accepts most of the state’s pumpkin crop.

“I do remember when crops got hit back then (1999); it was a pretty rough spell. But keep in mind that vining plants are more susceptible to disease than other crops,” Ackerman said.

Which is why Ackerman years ago began rotating his crop about every third year, one of Babadoost’s key pieces of advice to prevent the spread of Phytophthora.

This year, Ackerman is growing just ornamental varieties.
The disease caused by Phytophthora capsici affects all peppers and cucurbits, including pumpkins, watermelon, honeydew, squash, zucchini, cucumbers and other vine vegetables.

“It’s a nasty pathogen,” Babadoost said. “I’ve seen it destroy entire fields. Once the fruit is infected, it’s not suitable to process, eat, or carve.”

It can infect the foliage or fruit at any stage of development. In fields, infections typically appear first in low areas, where the soil remains wet for longer periods of time. Fruit rot generally starts on the area of the fruit that is in contact with the soil.

“To prevent this disease, we recommend crop rotation of three years or longer with non-host crops, followed by seed treatment and routine scouting, especially of low areas in fields,” Babadoost said.

“Management of this disease requires serious, intensive work by growers, processing companies and Extension personnel. In general, no single method provides adequate control,” he continued.

If Phytophthora blight is observed and localized, Babadoost said disking the area of infected plants to prevent the entire loss of a field. Fungicides can also be applied by commercial growers if there is no standing water in the fields. If growers choose to irrigate from a pond, it’s important to make sure the pond does not contain run-off from an infested field as the pathogen may be present in the run-off for the whole season.

“This disease is greatly affected by moisture,” he said. “The best way to prevent it is to keep the site as dry as possible. Home gardeners should water plants in the morning so the plants can dry throughout the day.”

Pumpkin harvests were down each of the past two years because of wetter than usual conditions, especially in central Illinois.

This year got off to “a much better start” than last, says Illinois state climatologist Jim Angel, with “warmer-than-normal temperatures through April and almost normal precipitation.” But May was cooler and wetter than usual, with rainfall a worrisome 1.5 inches above normal on the fields where Libby’s pumpkins were recently planted.