Once the fruit ripens, the lesions stop expanding. Fruit spots are not always obvious at harvest but develop 3-5 days after harvest. Fruit that is infected while ripe is called black mold and develops large, sunken, black lesions that may cover up to a of the fruit. Susceptibility varies depending on tomato variety and symptoms often appear on the side of the fruit that is exposed to the sun. The disease overwinters on decaying plant debris and is spread by wind and splashing rain.
Control is recommended through the use of resistant cultivars.
In recent years, late blight has become an increasing problem on potatoes grown in Wisconsin. This disease is more severe in cool, wet years. Fruit infections usually begin on the shoulders as the spores are dropped from the foliage above. Greasy, greenish-brown lesions are characteristic of this disease. The lesions enlarge until the entire fruit is covered.