What role do fertilizer and nutrients play in disease resistance

[SueCT]

How much do we know about the role of nutrients in plants ability to resist disease? I ask because I noticed a clear difference in the disease burden in my plants after I fertilized. I had posted pics of early blight which showed up earlier than normal in my plants this year. I had sprayed with Daconil a couple of times and was having trouble keeping up with the disease. I have been avoiding fertilizer because of high levels of some nutrients in my soil tests, although I was aware it was low in nitrogen. I decided to try going back to fertilizing anyway. I tried Texas Tomato Food. The result seemed amazing. Within a several days to a week, i stopped having new areas of early blight. I stopped spraying. I don't believe I sprayed at all after applying the fertilizer. Still, weeks later, no more early blight. Am I crazy? Is this just the effect of my earlier spraying that was delayed or took time to show up? If I had Early Blight in my garden early in the season wouldn't it have shown up on new growth later if I stopped spraying the Daconil? I don't want to jump to conclusions or make associations that are not valid. But I will keep fertilizing now. Even if I fertilize regularly and have no disease problems next year, since the temps and rainfall will likely be different also, not sure how to tell if it is the fertilizer making the difference or not. What say you oh wise Tomatovillians?

[AlittleSalt]

Sue, I wondered about the same thing...maybe not exactly, but close enough. I can't give you an answer or even a good guess for your garden. All I could do is tell you what it's like growing in an RKN and Fusarium 3 infected garden. I do not want to detract from your question in any way. I would like to reply though. (It's my 2 cents worth only)

I think using plant food/fertilizer is important as early as the plants can safely intake them to get them to grow as fast as possible. They need N Nitrogen that helps plant foliage grow. P Phosphorous helps roots and flowers grow (Roots Being more important at this point) K Potassium or Potash is important for overall plant health. A young healthy plant has a better chance at surviving plant diseases and otherwise negative conditions to-a-point.

I have my personal beliefs in using both organic matter and 10-10-10 fertilizer, but I'm not a fan of organic fertilizers. I know that many will disagree with what I just wrote, but over the past 3 years. The plants I fertilize with 10-10-10 produce tomatoes - The ones I've used countless brands of organic fertilizer don't.

[SueCT]

Thank you, Robert. All my plants produce tomatoes, fertilizer or not, although maybe they could be more productive. My soil tests show very high phosphate and Mg+ but very low nitrogen. I guess it would have been the nitrogen, which is very important for leave growth and production as you mentioned, that would have been what helped. Since it is so important for leaf development, and the leaves were what was infected with disease, it makes some general sense to me. As a nurse, I guess, it makes me think of how poor nutrition can lead to poor disease resistance. I don't believe the TTF is organic. I think they do make one that is, but it is a powder. At least they don't claim that the liquid fertilizers are organic. I don't know why they would not be, but I can't assume they are if they don't say they are. I have been using a lot of compost, but no fertilizer, either organic or not. It was actually 10-10-10 or phosphate free fertilizer that I think was recommended.

[AlittleSalt]

Sue, you are a nurse. I already liked you here - you just gained a whole lot respect from me. Thank you for doing your job.

[SueCT]

Awwe, you are welcome, Robert. Its funny, after 35 years as a nurse, only in the last couple of years have a few people thanked me when they found out I was a nurse, and it surprised me. It is also very nice.

[zipcode]

Originally Posted by SueCT

I guess it would have been the nitrogen, which is very important for leave growth and production as you mentioned, that would have been what helped. Since it is so important for leaf development, and the leaves were what was infected with disease, it makes some general sense to me. As a nurse, I guess, it makes me think of how poor nutrition can lead to poor disease resistance.
I don't believe the TTF is organic..

TTF is not organic, it has a few organic additives (a few % maybe), it's more a hydroponic fertilizer.
Nitrogen is generally considered a disease enhancer (if in excess), not the reverse, but if you are going to be limited by it, than it will most probably have a negative effect on health. Potassium is considered good for drought resistance and possibly general resistance. And then you have all those micronutrients in TTF which could help, copper, zinc, iron, etc, normally a clay based soil has them.
Recommended soil doses and reality don't match completely. In the way that you will get good results if you meet them, but still even better if you exceed them. I forgot where I read that dutch commercial growers consider good levels of potassium at least 3 times more than recommended.

[Labradors2]

SNIP

Originally Posted by zipcode

I forgot where I read that dutch commercial growers consider good levels of potassium at least 3 times more than recommended.

Isn't that interesting! I have read that a lot of the fert companies are reducing the amount of potassium in ferts these days because of the danger to aquatic creatures.

I have to be careful with fertilizers because my garden is close to our pond, and everything drains towards the pond

Linda

[bower]

SueCT, fertilizing to reduce disease is one of the first things I learned here at T'ville. My plants were always coming down with stuff as soon as they started to ripen their fruit. Fertilizing stopped that, and kept them healthy during the ripe cycle.

My opinion, based on observation, is that the typical tomato plant will start moving nitrogen out of the lower leaves when they run short. These leaves also become susceptible to whatever blight the variety is prone to, whether early blight, grey mold, whatever. Only a rare variety will drain the leaves and let them fall, just yellow, without disease. It just seems that whatever immune support is present, the plant stops sending that when the leaf starts to be used as a source of nutrients.

This year I tried a soluble fert from Promix with low N and high P and K. I was not entirely stoked about the results. Late season leaves are paler than they should be or have even yellowed in spite of being fed. The only clear result I got from feeding, is that there would be a flush of ripe fruit the day after. Compared to the usual ferts which have a decent amount of N (proportionally) I didn't see the renewed health and vigor which I normally get.

Thanks Linda for the heads up about excess potassium in the environment. News to me I'll have to look that up.

[brownrexx]

Just a guess but I would say that the fertilizer is allowing the plants to grow leaves faster than the blight can infect them. I don't think that the plant is resistant, it just has more volume of leaves.

Excess fertilizer runoff (mostly from farms) into streams is a big problem because it causes the algae to grow out of control which in turn blocks the light and lessens the amount of oxygen available to fish and other aquatic life.

[GrowingCoastal]

"This year I tried a soluble fert from Promix with low N and high P and K. I was not entirely stoked about the results."

ditto from two of us here

[Labradors2]

That's disappointing about the Promix - and it's not cheap either! I was going to try it next season, but now maybe I'll give it a miss

Is there anything organic and dissolvable that people recommend?

I use Tomato Tone in the planting hole, but don't want to sprinkle that around the top and attract critters.

Linda

[bower]

@ Coastal, good to know.
I keep thinking I need more K, but the 4-3-3- chicken manure product has given me the best results so far. Too bad it's not soluble for late season ferts in containers.

@Linda still didn't find anything on potassium runoff - all I see are the usual concerns about N and P. http://www.fao.org/docrep/w2598e/w2598e06.htm

[bower]

Originally Posted by Labradors2

That's disappointing about the Promix - and it's not cheap either! I was going to try it next season, but now maybe I'll give it a miss

Is there anything organic and dissolvable that people recommend?

I use Tomato Tone in the planting hole, but don't want to sprinkle that around the top and attract critters.

Linda

For solubles there are likely better things at the hydroponics store. Some billed as organic, too, so I hope there is an easy solution.

[SueCT]

I do have some leaves turning yellow, so I suspect the N in the fertilizer is being used up by now. I only applied the TTF once because it was already late in the season. I have always thought you were supposed to stop fertilizing by August. I could apply some now and see what happens. Interestingly, even with the yellowing leaves there is little or no disease. it just went away.

[bower]

Originally Posted by SueCT

I do have some leaves turning yellow, so I suspect the N in the fertilizer is being used up by now. I only applied the TTF once because it was already late in the season. I have always thought you were supposed to stop fertilizing by August. I could apply some now and see what happens. Interestingly, even with the yellowing leaves there is little or no disease. it just went away.

Now that you mention it, I remember reading some research about the effects of fish fertilizer on plant health, specifically. There was a thread about fish awhile back, darned if I remember whether or where I made any note about the stuff I was browsing, but if I find it will post.