Leaf water/sun scald or some disease?

[BlackThumb]

I was hoping to get some opinions on the following leaf condition.

Before the leaf developed any condition. I noticed that condensation and rain had a tendency to collect along the edges of these leaves for some reason. I typically water at night, but one night I was too tired and hot to water in the evening so I waited till morning when it just started to get light but hours before the sun directly hits these plants.






1: My primary suspicion is water simply collected along the edges of the leaves and a few other areas where I had noticed before the water was prone to collect; and this particular day was one of the hottest and brightest days this year; so the water acted like a magnifying glass to cause sun scald.

2: My secondary suspicion is that perhaps it is some sort of opportunistic virus, bacteria, fungus or mold that was attracted by the moist conditions where the water frequently condenses and collects on the leaves. Perhaps it was merely a coincidence that the leaf damage started a day after I watered in the morning and it was unusually hot and bright. I don't see any discoloration, slime, webbing, or powder that is typically present for a fungus, mold or mildew.

3: Perhaps it's something else I haven't thought of.

[RandyG]

This marginal leaf scorch is burn from fertilizer salts (coming from the soil or foliar applied) or some other material applied to the leaves that moved to the leaf margins and concentrated there. What have you applied to these plants and at what rate?

[BlackThumb]

Originally Posted by RandyG

This marginal leaf scorch is burn from fertilizer salts (coming from the soil or foliar applied) or some other material applied to the leaves that moved to the leaf margins and concentrated there. What have you applied to these plants and at what rate?

About three months ago I mixed in some blood meal into the soil at the prescribed rate a few weeks before transplanting the tomatoes into the soil. About three weeks ago I sprayed all foliage of my tomato plants with neem oil solution at the prescribed rate. About a week before the leaf burn I applied a spray solution of Mancozeb (flowable with zinc) to the foliage of all of my tomato plants at the prescribed rate. The last time I've fertilized them was about a week before the leaf burn appeared, I used tomato plant miracle grow at half the rate that is recommended and at the same time I also included Ebsen salt at half the rate prescribed and that was applied to the soil during watering as a solution. I have about 20 tomato plants of about eight varieties and this is the only tomato plant that is affected. It's a supersonic tomato plant and is in the same container with basil and a celebrity Bush tomato plant. None of the other plants in the container are affected. None the other plants in any of my other containers are affected. It's in a 10 gallon container with four small drainage holes that I inspect and clear weekly with a toothpick. Until about two weeks ago I was alternating a milk solution foliage spray one week, and the next week a baking soda solution foliage spray.

I have another supersonic tomato plant in another container that received the same treatment with no ill effects. However the plant with the leaf burn gets the most sun (of the two supersonic tomato plants) and gets the sun earlier in the day. The only plant that gets more sun is the celebrity Bush tomato plant that is right next to it that is unharmed.

It may very well be some sort of salt damage but it seems strange to me that only one plant (so far) is affected.

The container is closest to a neighbor that has a history of giving me trouble. I think it was a year ago the tomato plants in the location in the photo suddenly wilted (despite my efforts to try to save it for a week it became so bad that I pulled it out and destroyed it and all of the dirt and the container in case it was a poison or had a disease). Shortly after the plant suddenly became sick, I noticed that a bottle of windshield wiper fluid was missing. I was suspicious that someone stole the windshield wiper fluid and poisoned my tomatoes with it; in the same location in the previous year. I suppose it's possible that was and/or is some sort of sabotage.

Considering your opinion, I think I will water extra heavy and make sure that the container drains daily to try to flush out any excess salt or any other offensive chemical. I will also lay off fertilizer for a few weeks and discontinue Ebsen salt treatment for the rest of the year.

The last I checked all the containers had excellent pH (not perfect but almost in the center of the pH range recommended for tomatoes) without having to deliberately add things to change the pH. The pH was so close to the center of the pH range that I didn't think it would be worth the effort to fiddle with it.

I think you hit the nail on the head RandyG that it is marginal leaf scorch burn; and it's a good chance you're right about it being fertilizer salts or some other salts from some other source. Though I'm still considering the possibility that is something simple like Sun scorch. I will try to use preventative measures for both. Any more suggestions or opinions would be appreciated.