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Bitter Pit

In a development that could prevent millions of dollars' worth of wasted fruit annually, researchers in the college developed a test to determine whether "bitter pit"--a disorder that blindsides apple growers by showing up weeks or months after picking--will develop in stored Honeycrisp apples.

"The apple looks good," said Rich Marini, professor of horticulture. "You put it in cold storage for three or four months and take it out and it still looks good. You put it in room temperature for a few days and bitter pit develops. Only then do you see it."

Honeycrisps are extremely susceptible to bitter pit, which causes "corky" brown spots under the skin. Marini said the disease, which affects about 23 percent of Honeycrisp apples in Pennsylvania each year, is induced in the fruit by a calcium deficiency.

The findings, published in HortScience, describe a procedure to assess whether apples will develop bitter pit. Researchers air-dried peels and ground them into a powder, which was analyzed for calcium level. If it's low, it is a strong indicator bitter pit will develop in storage.

"The growers would like to know--what's the probability that their fruit is going to develop bitter pit in storage?" he said. "Depending on the probability of developing bitter pit, they can sell their fruit immediately and avoid the problem. So we are hoping that they can use the information generated by this research to decide which fruit they should sell immediately and which fruit they should put into storage."

--Jeff Mulhollem