Septoria Leaf Spot on Tomatoes


“I am looking for a paste-type tomato (or any other) that has resistance to septoria leaf spot. Do you offer anything for sale? Thanks. ~D.”

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Thank you for the email regarding tomatoes that are resistant to Septoria leaf spot. As of the most recent developments (Summer 2009 publications) by Virginia Tech and Cornell Universities on developing lines that are resistant, there are no varieties of tomatoes available in the home gardener market that are resistant to Septoria.

For now, your best options are:
Cultural Control
• Dispose of crop refuse by plowing under or composting.
• Control weeds in and around the edge of the garden.
• Rotate tomatoes with cereals, corn, or legumes. A 4-year rotation is recommended where disease has been severe. (In addition to tomatoes, other Solanacious crops like potatoes, peppers, eggplant, petunias, ground cherries, tomatillos, huckleberries, and datura should be kept out of the area.)
Chemical Control
• Apply fungicides on a preventative schedule before the disease first appears on the lower leaves. Begin sprays when the first fruits of the first cluster are vis¬ible after blossom drop. Apply fungicides every 7 to 10 days or more often when the weather is warm and wet. In home gardens the fungicides, chlorothalonil (e.g. Daconil 2787) or maneb (e.g. Maneb), can be used.
• In commercial plantings, chlorothalonil (e.g. Bravo, Terranil) and maneb (e.g. Dithane Rainshield NT, Penncozeb) can be rotated with the systemic fungicide, azoxystrobin (e.g. Quadris), every 7 days. Alternating sprays is important in order to delay the development of resistant strains of the fungus to azoxystrobin.

I’m sorry that I couldn’t provide more helpful information on this. If you have any other questions, please feel free to ask.

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© Mertie Mae Botanics LLC and Horticulture Talk!, 2010. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Mertie Mae Botanics LLC and Horticulture Talk! with appropriate and specific direction to the original content.

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