Landrey wrote:

I am having problems with black spots on the stems and leaves of my tomato
plants. I have about 10 plants and about half are affected. I have been
spraying them with Ortho Disease Control and removing the affected stems and
leaves but the problem seems to get worse. I have even been watering close to
the ground to avoid splashing dirt on the plant.

Is there any way to save my plants? I would rather not have to destroy them
and start over if I don't have to since I have invested a lot of time into
them.

Most likely it's blight. If you want to save the rest of the crop, you
have to completely remove the damaged plants now...I found this tidbit
online:

Early blight (Alternaria leaf spot) (Figure 5) is caused by the fungus
Alternaria solani. Symptoms become prevalent during the hotter months.
This disease produces brown to black, target-like spots on older leaves.
If severe, the fungus also attacks stems and fruit. Affected leaves may
turn yellow, then drop, leaving the fruit exposed to sunburn. Sanitation
is the best control. Remove all diseased plant tissue on the ground, as
the fungus overwinters on leaf debris. Do not plant tomatoes in the same
place next year. Space plants farther apart to improve air circulation.
Avoid overhead irrigation. If the infestation is heavy, sulfur dust may
help protect new leaves from infection.

I've had blight and it ravaged the entire crop in a matter of days. My
problem that year was that they were planted too close together so they
got no circulation and the disease spread quickly since the leaves were
touching eat other.

The same applies to potatoes. Neither should be planted near each other
and the same soil should not be used in subsequent years. If you're
unable to save that crop, plant the next one elsewhere....or perhaps
start another one in another spot now....well away from the diseased
plants. Also...don't compost the diseased plants - it'll just pass on
the disease (I never compost any part of the tomato plant - disease or no).


..

Zone 5a in Canada's Far East