Fruit with Bacterial Spot Not Pretty, But Safe to Eat

First posted on 06-26-2009

Consumers used to picture-perfect fruit at the supermarket might shy away from homegrown or locally produced fruits blemished by a common disease of peach, nectarine, apricot or plum, but fruits affected by bacterial spot are safe to eat.

“Bacterial spot, or bacterium Xanthomonas, is most severe after a wet spring,” said Michele Warmund, University of Missouri Extension horticulturist. “Rainfall during the three-week period after petal fall generally results in early-season infection.”

Infections affect the outer appearance of the fruit, but the flesh is safe to eat, she said. Infections appear as small purple or black flecks on the surface of peaches and apricots and as water-soaked spots on plums and nectarines. Pitting and cracking may occur in spots.

Removing the peel eliminates the lesions and makes the fruit more attractive when serving, she said.

Spring infections develop into darkened blisters near the tips of the twigs of last season’s growth. In some years, twig tip injury is so severe that the terminal bud fails to open, resulting in dead shoot tips on the tree.

To avoid the disease, plant cultivars with the highest resistance. Antibiotic products are available for commercial producers, she said. Foliar sprays of zinc plus lime or fall applications of copper do not provide reliable control and sometimes can cause foliar and twig damage.

Photo credit: MU Cooperative Media Group