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Hi All
We have been getting a big dose of rain here in Illinois. I have noticed a few of my tomato plants have a dark streak running from the ground up the main vine of the plants. I hilled-up all plants prior to all this rain. They were fed pumpkin power and Biomin Endo Plus with Calcium at transplanting. Most of the plant growth looks lush and green. I removed the first sets of all the blossoms and the lower branches and suckers, when our area received over 2" of rain in one day. All plants seemed to make it through this quite well. Again, most look healthy, but a few have this odd dark streak up the main vine. All are staked up as well. Any ideas? I have removed any affected growth as much as possible without over doing it.

6/25/2015 6:53:51 PM

Allentown, PA

Hi Biddy Goat,

It really sounds like Alternaria Stem Canker.

Alternaria alternata, a fungus which invades tomatoes that have been planted in infected soil, causes Alternaria stem canker. The fungal spores land on the plant when old tomato debris is disturbed or works its way up from the soil itself. Dark brown to black cankers develop at or just above the soil line, eventually enlarging and girdling the plant, causing its death. Disease is often spread when rainwater or overhead irrigation upsets spores.

Usually this is caused by heavy precipitation causing spores to splash up from the soil onto the stems and leaves.

It would be wise to remove the plant quickly due to it's ability to spread quickly to other plants. There is no successful management by fungicides.

6/25/2015 8:06:58 PM

Thanks Julia
I have been removing all growth from the soil base up to about 1 foot. All plants look really good today despite a load of rain which seems to be on going. I sprayed a biological fungicide on the plants this evening as well. I will keep a watch on them. I don't see the cankers or girdling you describe on my plants, so I think this is something else.
thanks
Julie

6/28/2015 9:14:17 PM

Allentown, PA

Thank God it's not stem Canker then!! Good news!! You are doing what you need to in order to slow down and hopefully stop this in its tracks then.

I'm waiting to spray my plants as well as it's been raining for days now.

6/29/2015 6:39:39 AM