|For the past two years I have been experiencing problems with my tomato plants. After they mature, the leaves turn brown and eventually the plant dies. I have been told that this is a wilt type disease and there is very little I can do to prevent this. I rotate my crops every year, so I know that it is not due to non-rotation of crops. Do you have any ideas?|
|Yes, Fusarium Wilt is indicated when the lower leaves get brown and die, followed by the upper shoots. Eventually, as you indicated, the whole plant goes. Generally it occurs on one side, then the other. By slicing the stem lengthwise near the soil line you can see some dark brown tissue about an 1/8th of an inch under the surface.
There are many strains of the Fusarium fungus, and each strain is specific to a different type of plant. Fusarium Wilt will stay indefinitely on plant debris or in the soil. It enters the plants through the roots and can be spread by seeds, tools, soil and plants. It spreads via the water-conducting vessels in the plant. When these vessels get clogged it prevents nutrients from getting to the leaves and fruit.
There is no control available. You need to destroy the infected plants. Do NOT put them in your compost bin! The best solution is to rotate the crops (which you appear to be doing already) and use plants that are resistant to fusarium wilt. This will be indicated on the plants when you purchase them.