The first apple scab spores of the season have been detected in both Pennsylvania and New York orchards, according to a recent report from Kari Peter, a Penn State Biglerville tree fruit pathologist.

Apple scab overwinters in infected leaves on the orchard floor. Spores from the dead leaves are produced in the spring and can cause primary infection of fruit. <b>(Good Fruit Grower file photo)</b>

Apple scab overwinters in infected leaves on the orchard floor. Spores from the dead leaves are produced in the spring and can cause primary infection of fruit. (Good Fruit Grower file photo)

Cornell University plant pathologist Dave Rosenberger reported spores being found in abandoned orchards near Red Hook, New York, on March 7. Two days later, Peter reported finding spores on trees at the Biglerville Fruit Research and Extension Center.

She said infection wouldn’t start until there is green tissue and an infection period. Still, it’s time for preventive measures.

“Since trees are pushing due to the warm weather the last several days,” she said, “now is a good time to apply dormant copper sprays to manage diseases.”

Get out the spray rigs to apply dormant copper sprays on apples and pears for fire blight and scab and on peaches for bacterial spot and peach leaf curl.

“Aim for two pounds per acre of metallic copper, so pay attention to the percent metallic copper equivalent listed on the label of the copper you use,” Peter said.

– by Dave Weinstock