Who has enough acreage to change plots every year for 3 or 4 years? Not I! :-)

Well I use about a third of my vegetable garden for tomatoes and do change it every year but still have fungus problems so don't think that is any cure.
Fungus control has to start early and be kept up on a weekly basis as it is a preventative not a cure.

Changing locations for tomatoes every 4-5 years helps cut down on splashback reinfection, but since ALL NEW infections of foliage, be they bacterial or fungal, are airborne, changing locations cannot and will not stop foliage infections.

And yes, only those with lots of room can even attempt to cahnge locations.

But the fungal foliage diseases usually progress the fastest and there is a good antifungal, Daconil, which will prevent the two most common fungal foliage diseases if the plants are started on a spray schedule right after they're put outside.

So Ortho Garden Disease Control, aka, Daconil is something to consider.

And rather than have this thread get into Dacil discussions I suggest that anyone interested do a search, bottom of this first page, b'c there are many many threads here about Daconil for those interested in reading about it.

There is not an equally effective preventative for the bacterial folaige diseases altho a few products might help a bit.

Carolyn

Teal,

Whether the fungal spores infesting your tomato plants are airborne or arrive by some other means or host, there are three major factors, besides the pathogen itself, that must exist for the disease to progress to the point of damaging your plant: susceptibilty of the host plant, favorable environment for the fungal spores to develop, and time.

So, assuming fungi indeed is the pathogen you're dealing with and you have no control over airborne fungal spores landing on your tomato plants, you can remove or reduce one of the other three factors, and hopefully reduce or eliminate your loss ... since the disease cannot progress without all factors interacting.

To reduce or eliminate the susceptibility of the host plants: Select varieties that are resistent to the diagnosed fungal disorders. The horticultural agent for your county may be able to give you some suggested choices in this regard.

To reduce or eliminate the favorable environment for fungal spore development: Use drip or soaker hose irrigation, put plants in a location where sunlight will dry dew or rain rapidly, prune or otherwise provide ample air circulation through the foliage, apply a product that will block the spores from entering the stoma in the epidermis of the leaves.

To reduce or eliminate the fungal spore itself, you can apply a product that kills the fungal spore. Proper identification of the pathogen of course is necessary to determine the product you will succeed with. You also can remove the infected vegetation before the pathogen spreads and achieve some degree of success without chemical applications ... but surgery doesn't necessarily remove dormant remaining factors.

And remember time is a factor in disease development. It takes time for the pathogen to interact within a favorable environment on a susceptible host plant to a degree that evolves into a threatening disease. You may have a susceptible host plant, a pathogen spore present and the environmental conditions necessary for the pathogen to awaken, but it still takes time for the pathogen to invade the plant tissue.

For example, an airborne fungal spore, even though present on the surface of a tomato leaf, and even in the presence of sufficient water to hydrate, still requires hours to move to and through a stoma in the leaf epidermis and destroy the interior mesophyll cells. So, reducing the amount of time the spore remains hydrated can reduce opportunity for disease development.

So, remember in summary ... a fungal disorder requires, besides the pathogen itself, a susceptible host plant, a favorable environment, and time to develop. Remove one of the factors and reduce or eliminate the disease.

tealboy im not sure how long you been growing and having problems growing tomatos in florida but i do know alot of florid growers are losing alot of plants to tomato yellow leaf curl virus,TYLCV.You probably have allready heard of it,if not do a google on it as it might be part of the problem.

mulch really helps with tomato fungus diseases too. I save leaves from mulching my banana plants and put them under the tomatoes to keep fungus from the soil splashing up on the bottom leaves. it has helped SO much!!!

I got wiped out this year, and I probably have the LEAST favorable environment for getting fungal diseases, here in Los Angeles County. We are in the midst of a really ghastly drought. The plants were south-facing, watered by a soaker hose buried under landscape fabric and wood mulch. While the rest of you couldn't walk outside without getting drenched, we only had a couple of days of rain all year. The only overhead watering my plants received was from my hand-pump sprayer full of either kelp or daconil. (The Mancozeb seems to work much better -- very glad I switched to that.)

I suspect my blight problems were just a secondary problem to whatever else was afflicting my plants. Sort of like a "secondary infection." I'm still not sure what the primary infection was, if anything, but it probably started from clumsy over-watering with the soaker hose.

One thing I noticed, and I would appreciate other, more knowledgable, people's opinion on this, was that whenever I trimmed off dead leaves and branches, the problem got much worse within two days. Not just a steady march of disease, but, WHOOSH, a rapid spreading of disease to untouched, untrimmed branches. I finally just decided to hell with it, I'm not going to cut anything else off. I had been snapping off branches by hand. Not messing with things and spraying with Mancozeb seemed to slow down the progress. Now when I trim I am using scissors and a bleach-soaked rag to clean them after every cut.