Helping tomato plants survive blight in Ohio - Ask Extension
I have been attempting to grow tomatoes in Butler Co, Ohio but my plants get wiped out by blight every year. I mulch with freshly purchased cypress mu...
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Helping tomato plants survive blight in Ohio #811565
Asked September 20, 2022, 2:47 PM EDT
I have been attempting to grow tomatoes in Butler Co, Ohio but my plants get wiped out by blight every year. I mulch with freshly purchased cypress mulch so splashing of water with spores from the bare ground cannot occur, remove the bottom parts of the tomato plant so the spores cannot splash up from the ground onto them and remove any blight parts of the plant as soon as it appears at the bottom part of the plant and still when the blight starts it quickly consumes the whole plant. Black spots that quickly turn into large discolored areas turning brown and the leaves quickly fall off. This year I used Captain Jack's Copper Fungicide (copper octanoate) August 7th when I first saw the black spots but it did not slow the progression of the blight. I was lucky to harvest some of the tomatoes when ripe to enjoy them but on Sept 8 of this year I pulled all my plants out of the ground and destroyed them with their spores so they would not remain in my soil to destroy my plants next year. The plants were literally decimated with blight and all the leaves falling off when I destroyed them. The soil I use in my raised bed garden is a well drained soil from a local bulk supplier. Please tell me what I need to do to grow tomatoes to survive the blight. Is this typical of Ohio? I thank you very much for any help you can give me. After attempting to grow tomatoes in Ohio for several years I am clueless.
Butler County Ohio
Expert Response
Hello,
There are several diseases that can cause leaf spots as you describe on tomatoes, septoria leaf spot, and early and late blight. These are all caused by soil borne fungal spores and are common in Ohio and the midwest. It sounds like you are following many of the cultural practices recommended to combat leaf spot and/or blight on your tomatoes.
Other recommendations I have are:
1 - Avoid growing tomatoes or any other plant in the Solanaceae family (eggplants, potatoes, peppers, etc) in the area for 2 years.
2 - try using landscape fabric to cover the soil under and around the tomatoes instead of mulch. This may provide more of a barrier against splashing
3 - use drip irrigation to water your tomatoes instead of an overhead sprinkler.
4 - stake tomatoes rather than using tomato cages and space plants far enough apart that there is adequate air circulation to help keep leaves dry.
5 - if you do wish to use the copper fungicide you mentioned, start this earlier in the season before the fungus appears. Be sure to read and follow closely all label directions.
These two articles from USDA and Michigan State University have more information on combatting these issues.
One other thing to know is that plants in the Solanaceae family should not be grown under or near walnut trees. The juglone in walnut trees can cause a blight on tomato plants. Any plant debris from walnut trees can also cause this issue.
This article from University of Nebraska has general information on growing tomatoes and addresses the issue with juglone as well as other diseases of tomatoes.
There are several diseases that can cause leaf spots as you describe on tomatoes, septoria leaf spot, and early and late blight. These are all caused by soil borne fungal spores and are common in Ohio and the midwest. It sounds like you are following many of the cultural practices recommended to combat leaf spot and/or blight on your tomatoes.
Other recommendations I have are:
1 - Avoid growing tomatoes or any other plant in the Solanaceae family (eggplants, potatoes, peppers, etc) in the area for 2 years.
2 - try using landscape fabric to cover the soil under and around the tomatoes instead of mulch. This may provide more of a barrier against splashing
3 - use drip irrigation to water your tomatoes instead of an overhead sprinkler.
4 - stake tomatoes rather than using tomato cages and space plants far enough apart that there is adequate air circulation to help keep leaves dry.
5 - if you do wish to use the copper fungicide you mentioned, start this earlier in the season before the fungus appears. Be sure to read and follow closely all label directions.
These two articles from USDA and Michigan State University have more information on combatting these issues.
One other thing to know is that plants in the Solanaceae family should not be grown under or near walnut trees. The juglone in walnut trees can cause a blight on tomato plants. Any plant debris from walnut trees can also cause this issue.
This article from University of Nebraska has general information on growing tomatoes and addresses the issue with juglone as well as other diseases of tomatoes.
