One of my two mature, productive tomato plants wilted last week. Surprise! My previous article (was it just five weeks ago?) about wilting tomato plants was more timely than I knew.
This is the story of what happened.
We had rain. The rain in our area has been patchy, so the rain in my yard may not be like the rain in your yard, but one day we had about 10 hours of steady rain. When I looked out the front windows the next morning, thinking that the garden would probably look great after all that water, I saw that one of my tomato plants had wilted.
I thought back to my previous article about the steps to follow, to figure out what happened to my plant.
At the very least, I can say with confidence that dry soil was not the cause of the wilting.
The plant hadn’t wilted only on one side, and it wasn’t merely slightly droopy. All the leaves on the entire plant were hanging limp on the branches, and smaller branches were sagging.
At first, I thought “cool, bacterial wilt”, since the wilting was so sudden.
Checking for Bacterial Wilt
This is a disease I have seen only once, but I knew that one sign of bacterial wilt was sudden wilting of the entire plant.
Often, this wilting takes place in hot weather and moist soil.
I trimmed off leaves and branches to do the bacterial wilt streaming test. If bacterial wilt was the cause, then white cloudy ooze should stream out of the branches when they were suspended in water.
When the first couple of leafy branches failed to produce the white cloudy streaming that I expected, I cut a thicker section of stem to add to my jar of clear water, to see if maybe I just hadn’t used a big enough section of branch. Ten minutes later, the water was still clear.
Looking at base of the plant for more clues
Then, I finally looked at the base of the plant, where the stem emerges from the ground. This was when I thought “uh oh”. There was white fungus-looking stuff right near the base of the plant and climbing up the stem.
To be honest, this is probably a bigger problem than bacterial wilt would have been for the future of my garden. My knowledge of white fungus climbing up stems from the ground leads me to think the fungus is Southern Blight. (Link is to a pdf about Southern Blight from University of Kentucky)
Lots of fungal diseases are host-specific. That means that they can infect only a limited number of crops. Southern Blight, on the other hand, can infect many kinds of crops.
How can I reduce future damage from Southern Blight?
I already removed the plant, including as much of the root system as I could. University of Kentucky’s information (linked previously) recommends removing the soil in that area, too, to reduce the number of reproductive bits, called Sclerotia, in the garden.
The next recommendation that organic home gardeners can follow is to grow plants that can resist Southern Blight in that area for a few years.
The other recommendation is to raise the soil pH a bit. The fungus grows more slowly in higher-pH soils.
The good news: no evidence of root-knot nematodes
If there were root-knot nematodes adding to the damage, the roots would look lumpy. Maybe other gardeners are not as relieved as I am to see this lack of lumpiness, but some years my garden is seriously affected by the nematodes.
Where did the Southern Blight come from?
This is hard to know. My garden has never, until now, shown any sign of harboring Southern Blight. The disease can travel on infected plants, mulches, soil, and contaminated tools. I am thinking that it could also be spread by ground-scratching birds, but they are not mentioned in any of the publications I checked.
A new tomato plant growing nearby
At the end of June, when we returned from five weeks of travel and before we drove across Texas to visit family in the Austin and Houston areas, I planted two tomato seeds in the garden. Luckily, they are in a separate garden bed from the blighted plant.
I set the seeds inside a collar formed by a paper cup that had the bottom removed. The collar was to help hold moisture and to protect the seeds from being eaten. I watered the area well before we got in the car and headed west.
Amazingly, when we got back from our 8-day tour of relatives, a little tomato plant was standing where I had planted those two seeds.
I had planted some Swiss chard and a leaf-amaranth in the same little garden area, and they were coming up, too. A caterpillar of some kind found those to be delicious, so I had to replant the greens, but all is looking good now.
That little tomato plant has flowers on it today. If all goes well, there will be more garden-tomatoes coming into my kitchen by late September, and, hopefully, the potential disaster of Southern Blight will not be causing too many more problems.