Knowledgebase

Alternaria leaf spot? #938449

Asked July 07, 2026, 8:02 PM EDT

I have been having an increasing problem with this on my tomato plants each year. It seems to start in June and spreads throughout the plant causing defoliation. If this is early blight, then I will follow the recommendations going forward. I have always piled all my garden material at the end of the season in an open sided bin where earthworms work it down to mostly castings which I return to the barrels in the spring (I grow in half 55-gal plastic barrels). I alternate which barrels have tomatoes, peppers and eggplants each year. I really like your site for identifying and managing plant diseases. Thanks!

Mendocino County California

Expert Response

Unfortunately, our group cannot answer your question because it doesn't serve your location. Please contact your local Cooperative Extension office for assistance. A good way to find your local office is to go to https://extension.org/search/ and enter your county or parish name along with your state name. You might also use your favorite search engine and enter "cooperative extension" along with your county name.

Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied July 08, 2026, 9:08 AM EDT

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