This is one of the most destructive diseases in all areas east of the Rockies. Symptoms are first visible about 3-5 weeks after petal fall as small, water-soaked, browning lesions. Early symptoms on fruit can be mistaken for insect damage. During periods of high humidity, gum may exude from these lesions.
Currently there is no specific spray product completely effective for controlling bacterial spot. Spraying with a soil inoculant containing the naturally occurring bacterium Bacillus subtilis or using a harpin protein-based product at 1/4 teaspoon per quart of water (or a 0.35-ounce pack per 3 gallons of water) as a preventive spray will increase plant vigor, which will, in turn, help to fight the disease. We recommend Plant Guardian™ Liquid Concentrate and Green Guard™ Plant Growth Enhancer. Fertilizing with Fruit Trees Alive!® according to label directions is also a critical step in helping trees fight problems.