tomato disease

Asked August 3, 2015, 3:49 PM EDT

I only have 5 tomato plants & a very small garden. This year one plant (Jet Star) seems to have bacterial speck. (Curled leaves and pinprick sized black specks all over the fruit. I believe that the plant had the disease when I bought it. Do I need to throw that plant out in hopes of saving the other 4? Or can it be cured? What do I need to do to protect the plants and future plants? I read something about a copper spray but who sells it? Thank you.

Anoka County Minnesota

1 Response

Thank you for the question. You don't need to throw the plant out to save the others and you can enjoy the tomatoes from this plant by cutting out the spots. You can reduce the spread of disease now by avoiding working on your plants when the leaves are wet, providing good air movement around the plants by staking or caging, pulling weeds, and spacing plants far apart enough to allow the leaves to quickly dry. This fall, clean up and discard all plant residue because the bacteria survive our winters in the plant debris. Next year, plant tomatoes in a different location. Allow 2-3 years before you plant tomatoes back in this same spot. Control of disease is generally most effective when measures start before the disease appears, usually when the plants are 6 inches tall. Your tomato already has the infection so any fungal sprays are likely to be ineffective. It's also a bit late to spray the tomatoes that don't currently show disease. Some strains of bacterial speck are resistant to fungicides and usually several products need to be rotated to be effective. Using several products gets to be logistically difficult because of the length of time one must wait between application of a product and when the fruit is safe for consumption after a thorough wash. This time period will be listed on the product label.
I can't tell you where to buy these products but I can tell you that you must read the product label completely and it must specifically state that it is for use on tomatoes with bacterial speck. The label is the law. Go to local hardware or big box stores and read the labels of the various products. Here is a Clemson Extension publication on tomato diseases. It lists fungicide control products by name for use on tomatoes in home gardens, and lists of tomatoes that are resistant to bacterial speck and other diseases
To learn more about bacterial speck and growing healthy garden tomatoes, read these two publications: