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Bacterial Leaf Spot Disease

bacterial spot

Bacterial leaf spot disease produces small, dark irregular spots on tomato and pepper leaves; leaves eventually turn yellow and drop off. This defoliation weakens plants and exposes developing fruits to sunscald. Small, dark, wartlike raised spots with slightly sunken centers may appear on green fruits. Rot organisms are able to enter the fruit at these spots and cause decay. Bacterial spot symptoms are similar to, and often indistinguishable from, bacterial speck.

Very warm, wet weather encourages the development of the disease. The bacteria overwinter in plant residues. This disease is a problem mainly in the East and Midwest.

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Written by Stephen Albert

Stephen Albert is a horticulturist, master gardener, and certified nurseryman who has taught at the University of California for more than 25 years. He holds graduate degrees from the University of California and the University of Iowa. His books include Vegetable Garden Grower’s Guide, Vegetable Garden Almanac & Planner, Tomato Grower’s Answer Book, and Kitchen Garden Grower’s Guide. His Vegetable Garden Grower’s Masterclass is available online. Harvesttotable.com has more than 10 million visitors each year.