Problem Identifier Unit Screen//v.w/ RR Template

Problem Identifier Unit Screen//v.w/ RR Template Sunscald

Problem
On green and ripening fruit, a light patch develops on the side facing the sun. This area blisters, and finally becomes slightly sunken and grayish white, with a paperlike surface. A black mold may grow on the affected area, causing the fruit to rot.

Analysis
Sunscald occurs on tomatoes when they are exposed to the direct rays of the sun during hot weather. It is most common on green fruit, but ripening fruit is also susceptible. It is most prevalent on varieties with sparse foliage and on staked plants that have lost their foliage because of leaf diseases, such as early blight, late blight, or septoria leaf spot, fusarium wilt (see Fusarium Wilt), verticillium wilt, or leaf roll. Fruit on plants that have been pruned to hasten ripening are also subject to sunscald. Tomatoes are still edible if the sunscalded area is removed. Rot fungi frequently invade the damaged tissue, resulting in moldy and inedible fruit.

Solution
Cover exposed fruit with straw or other light material to protect it from the sun's rays. Do not prune leaves to hasten ripening. Control leaf diseases. Grow verticillium and fusarium wilt-resistant varieties (for a list, see Disease Resistance of Tomatoes).