Signs of lack of water or excess heat?

Agriculture and soil. Pollution control, soil remediation, humus and new agricultural techniques.
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to be chafoin
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Re: Signs of lack of water or excess heat?




by to be chafoin » 12/08/18, 15:33

Did67 wrote:Excess heat, outside, the tomato does not know: my tomatoes in my greenhouse (not the open tunnel) have cooked up! I harvested tomatoes, mature, but cooked on the outside!
And the aggressive sun, on the tomato: never at home. She grows in Lanzarote !!!
I would not be so categorical, both for the heat and the sunshine. In my opinion beyond 35 ° the stomata of the tomato plants are closed and the photosynthesis is disturbed. In my case I am afraid that several factors have come into synergy negative: sudden jump in temperatures upwards, sudden and prolonged sunshine, lack of water, no sufficient drop in temperature at night ...
If I compare the climates of Lanzarote and Bordeaux, I find that the summer months are sunny towards my home!
Finally there may be burns on tomato fruits:

code: Select all

Les températures excessives, liées à une forte in-solation directe, favorisent l’apparition du
blotchy ripening – taches jaunes sur fruits – ainsi que du« collet jaune » chez les variétés à fruits à collet vert. Elles peuvent également entraîner des brûlures plus sévères sur les fruits.

https://fr.scribd.com/document/61256418/FT-tomate
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Re: Signs of lack of water or excess heat?




by to be chafoin » 12/08/18, 15:45

And to continue with this idea, I note that market gardeners operate the "bleaching of the shelters" in the summer in order to lower the temperature of the greenhouses by 5 ° and precisely to avoid problems such as "black ass" on tomatoes ...
http://www.grab.fr/wp-content/uploads/2016/06/6-fiche-blanchiment-des-serres-refbioPACA-maraichage-mai-juin-20%E2%80%A6.pdf
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Re: Signs of lack of water or excess heat?




by Did67 » 12/08/18, 23:13

You can't compare plants outdoors with what happens in a greenhouse, which overheats and becomes a real dryer. I harvested in mine, however the doors are removed at both ends, "cooked" tomatoes (soft on the outside as when you soak them in boiling water when you want to remove the skin).

The document you are quoting concerns tunnels.

But you are free to think what you want.

For my part, in our climates and for feet outside, I doubt that it is an excess of sun! In Mexico, Peru, California or Tuscany, the tomato is cultivated in the fields, on thousands of hectares.

I have grown in the heart of Chad, and there, the sunshine, dry season is something else: I had the top of the ears that burned - burns in the second degree!

I do not say either, read again, that photosynthesis is not affected, nor that stomata do not close: they are normal phenomena of regulation of plants. But it does not cause yellowing! We started from yellowing.

Similarly, difficulties in fertilization / fruiting may appear ...
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Re: Signs of lack of water or excess heat?




by to be chafoin » 13/08/18, 00:35

Did67 wrote:For my part, in our climates and for feet outside, I doubt that it is an excess of sun! In Mexico, Peru, California or Tuscany, the tomato is cultivated in the fields, on thousands of hectares.
I have grown in the heart of Chad, and there, the sunshine, dry season is something else: I had the top of the ears that burned - burns in the second degree!
I do not say either, read again, that photosynthesis is not affected, nor that stomata do not close: they are normal phenomena of regulation of plants. But it does not cause yellowing! We started from yellowing.
Yes, you are probably right to put the context of the yellowing back on the table, I assumed, moreover, following your message, a problem with the secondary roots (see above). The thread still started from the same foot on which I took a picture of the black asses. Well apparently it would not be a direct problem of sunshine either (maybe rather the lack of irrigation or the same problem of the roots, but I find it difficult to form an opinion on that ...). But above all, there is all the "damage" in my crops following the heat wave and drought ...

I reacted after reflection to "the aggressive sun, never at home", while I see for example burns on my fruits like:
2018-08-11 11.54.25.jpg
So here is another foot
These burns seem well recorded and:
The still green fruits of field crops are particularly vulnerable.
. http://ephytia.inra.fr/fr/C/5182/Tomate-Brulures-solaires-des-fruits

Are you saying that in Chad they do not have a sun aggression problem on their vegetables? Are the cultivars different?

I know very well that tomatoes are grown in the open in California, Italy or elsewhere. That said, if you are talking about the industrial tomato, the varieties are tampered with to have a much more resistant skin, so as not to be crushed at the bottom of the bins by tons of tomatoes or during the various stages of their transport. You can throw them to the ground they don't crash! All this for performance stories. I also recommend on this subject the rather hallucinating documentary "the empire of red gold". So obviously in this case it has nothing to do, including for sensitivity to the sun!
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Re: Signs of lack of water or excess heat?




by Did67 » 13/08/18, 10:37

Ah yes.

I had this in my greenhouse, although it was always open. Where the fruits have also "cooked" on the stalk. On a fake heart of beef (a hybrid with hard skin - a "long life") as on the real heart of beef next door! But not in the tunnel open to the four winds ...

So if you had this outside, then indeed ... Solar burns.

It is also correct that the "industrial" varieties are selected: they are of determined growth and therefore stop; the tomatoes ripen and harvest by machine. And they have a tough skin to take it all.
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Re: Signs of lack of water or excess heat?




by to be chafoin » 20/08/18, 22:38

Same questions about the cause (s) of this degradation of plants:
2018-08-18 13.33.33.jpg
Leaves turn yellow, then burn partly before drying.

The stalks also brown.
The damage sometimes takes place in the middle of the plant.
2018-08-18 18.40.31.jpg
Down rather green, in the middle brown, at the top it goes green!

Ideas for diagnosis?
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Re: Signs of lack of water or excess heat?




by Moindreffor » 21/08/18, 14:44

Well I think it's mildew, not as lightning as some years but it must be, I have a little the same thing
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Re: Signs of lack of water or excess heat?




by Did67 » 21/08/18, 17:27

Mildew or "equivalent" [fungal disease of the same type, but the genus of the fungus is different]: early blight, Sigatoka, etc ...

Sometimes you have to be a specialist to recognize them ...
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Re: Signs of lack of water or excess heat?




by Adrien (ex-nico239) » 22/08/18, 02:08

Did67 wrote:Mildew or "equivalent" [fungal disease of the same type, but the genus of the fungus is different]: early blight, Sigatoka, etc ...

Sometimes you have to be a specialist to recognize them ...


It is a little what I advanced above.

We are far from having the knowledge and the means to diagnose precisely all this.

Personally I do not care, if it grows so much better and if it grows so much worse as anyway neither I change the weather nor I swing insecticide ...
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Re: Signs of lack of water or excess heat?




by Did67 » 22/08/18, 08:28

Where it is useful to know if it is "mildew" or its "cousins" is if you want to put your tomatoes in an open tunnel ...

We have, vis-à-vis tomatoes, very different soils. Here, it condenses very quickly or rain often, elsewhere no.
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