Apple growers in the eastern U.S. have a despised enemy known as apple scab — a disease caused by a fungus that forms ugly brown or greenish-black pockmarks on the fruit’s skin. A scabby apple is unfit for grocery stores because consumers are notoriously picky about blemished fruit.
Growers have kept the disease under control for decades by spraying trees with pesticides. Now, researchers say the chemicals may be losing their effectiveness as apple scab becomes ever more resistant, worsening the threat of outbreaks in commercial orchards.
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