In the past I always waited for signs of disease before spraying,

What kind of disease are you having problems with? Fungal, like septoria spot or early blight? Or is it something else? And what have you sprayed with in the past?

Thanx suze9=Something that starts turning leaves yellow and it spreads from plant to plant, except cherry and roma tomatoes. I used Daconil in the past.
It seems to happen after the temperature gets high and alot of rain in June.Tomatoes and everything else looks great right now.Hurricanes have not been too nice the last couple of years either..lol

Just yellow leaves? From the bottom up or what distribution?

No spots on those leaves?

No wilting?

it would be important to know if you're dealing with a soil borne systemic disease such as Fusarium or Root Knot Nematodes, both of which are prevalent in many areas of FL, or whether you're dealing with foliage infections, all of which are airborne when they first initiate infection, although splashback reinfection the next year from contaminated soils from the previous year can be a problem,

If it's a systemic disease problem there's no spray that will help unless it's an insect mediated virus one where insect control might help. If it's a foliage disease, especially a fungal one, the spraying can help.

have you looked at the problem Solver #2 thread here to see if you can match up any symptoms from the links that are given? The TAMU link is one that's pretty good. The problem with making a diagnosis from pictures is that pictures are static while disease development is progressive.

So in addition to looking at that thread it might help to describe in detail ALL symptoms you see as Suze, and now me, are asking for.

Carolyn

suze9 & Carolyn
Seems like the yellowing starts at the bottom and works it way up. I remember small brown spots I think. Seems like there was wilting too, but not sure.I will have to wait and see. Problem is...once it starts, seems like the Daconil does not work. It spreads. But the last 2 years the gardens were blown away from all the hurricanes and tropical storms.John

Based on your desciption so far -- spreads from plant to plant, kicks in during high heat and rain/humidity, starts at bottom, etc., you see spots, etc., it's probably fungal (likely septoria or early blight). But I would still encourage you to look at the pics in the TAMU problem solver.

I would agree/recommend that Daconil is best used as a preventative under those conditions. In my personal experience, if I wait for signs of fungal disease before starting to spray, I'm constantly playing catch up, and the plants don't do nearly as well.

Overwatering/too much rain can also contribute to leaf yellowing.

suze9 & Carolyn
Well I waited and sure enough the yellowing started.Then they turn brown and die (leaves/branches) Bottom branches and then it runs up thru the plants. Seems to be spreading. No rain for 2 weeks. I water late in day usually, at base of plant.Temps have been close to 90 for a week now.I saw a few threads with this problem while trying to find mine. Seems like the crowd is split on preventative spraying. I sprayed 2 days ago but the yellow leaves continue. I thought we were supposed to water regularly but I see alot of folks say to let em dry out. I have been watering every other day or every day. Sandy soil with leaves/mulch mixed in. Also, i cover the ground with leaves to prevent weeds. Any problems with my methods? Not happening to my Roma or cherry.

"Yellow leaves" that "turn brown and die" is kind of vague. There are several conditions that can cause this.

Have you looked at the TAMU tomato problem solver yet? If not, please take a few minutes to do so (help us to help you).

As far as the spreading you're now seeing (if it's fungal) is likely a result of the fungal spores that got a foothold and multiplied during spring rains.

Again, based on your description, sounds fungal. Are you seeing any spots or lesions? If so, compare those spots with pics of ones in the tomato problem solver.

Here is a link that might be useful: tomato problem solver

I checked out the problem solver and so many of the examples look like my leaves. I took a photo to attach but how do you attach pic? I don't have a web site. I would think this forum would have an easy way to attach pics. I imagine it is something to do with URL but don't know.
But I am thinking i should spray again even though it has only been 3 days since I sprayed last. Remember that we have not had rain, i water at the base of plant and temps are in the low 90's for last week.One thing I forgot to mention that could be a problem. I use 6 ft. rebarb for plany stakes, but still use those dreaded 3 ft. tomato cages for some dumb reason>..AND I always feed the limbs in the hoops and it compacts the first couple of feet of the plant. Not much air circulaton. Don't ask me why i still do this. Guess I figure it supports the limbs n tomatoes somewhat.

To read about how to upload images, go to the top of the forum page and click on the black bar that says 'Image Uploading'. You can only upload an image when starting a new thread, so you'd need to start a new post.

Alternatively, use one of those free image hosting services like ImageShack, Photo Bucket, etc.

If it hasn't rained, and it's only been three days, there's no point in spraying again. Daconil works by sealing the attachment sites for fungal spores; it doesn't actually kill existing spores.

I like to keep my plants cleaned up below the first fruit set for good air flow. Just the foliage, I don't prune off suckers.

Suze9...thanks I will try to upload a pic of my problem.Lets see...I will call it.."Leaf Problem Photo"
How is that for original? ha!
John

Key questions, are there numerous small brown or black spots on the yellow leaves?

Do the yellow leaves come up evenly from the bottom, or is it predominantly up one side of the plant?

barkeater Did you look at photo at my new thread called "Leaf Problem Photo"? It is near the top of this forum at this time. The problem seems to start on the bottom of plant and can go up any where on the plant. Usually up one side and all the way to the top of plant on some. Plants are about 3 or 4 feet high. Romas and cherry are not affected yet. Just the Big Boys ( I think that is what they are. I just remembered seeing DISEASE RESISTANT and i was sold..hmmmm