The vegetable garden without getting tired

[Doris]

I was talking about short cycle onions (therefore winter) ... I did not know all these sites (except Baumaux and Promise of flowers) ...

Ok. I was talking about the ultra resistant tomatoes, mentioned on wallowgreen.

[Did67]

Ok. I was talking about the ultra resistant tomatoes, mentioned on wallowgreen.

Yes, that's what I understood. It is true that my sentence was very ambiguous. This is called jumping from rooster to donkey!

[stephgouv]

In summary, we can therefore say that today (given climate change), it is better to cultivate new varieties than old ones?

[Doris]

In summary, we can therefore say that today (given climate change), it is better to cultivate new varieties than old ones?

For me it's not quite that, I would say that we have to diversify. I have had old varieties that have been very sick and have recovered. But next year, for sure, I will put one or two ultra resistant kinds in my mix.

[Did67]

In summary, we can therefore say that today (given climate change), it is better to cultivate new varieties than old ones?

"it is better" is a judgment ... I avoid. Everyone does what they want!

But yes, if you want to produce tomatoes in the bad years (years with diseases), you have little luck with the old ones, despite "treatments" (if we rule out hard chemistry, systemic synthetic fungicides - those that act from the inside, circulating with the sap). Even if I will show that the key is to control water - I have, in my tunnel, "classic" varieties, rather sensitive, quite nickel (beef heart, Berao, Bern rose).

You even need "ultra-resistant" ones: my "old" hybrids (Maestria, for example; I don't have many witnesses: old seeds, a lot of germination losses), outdoors, are very affected! The "mildew" has for a long time "cracked" their resistance.

But the link with climate change is not obvious: because if we have more and more heat waves, on the contrary, this favors the cultivation of sensitive varieties (but creates other problems: burns, reduced fertilization). .

I'll explain it in my upcoming video: a major change took place in the 90s; strains of type A2 were imported; since then, mildew can reproduce sexually in us, which allows it to evolve and become much more virulent at speed V!

[Downy mildew has no sex, but it is now known that there are two types: A1 and A2. Basically, it works as if one is the "male", the other the "female". Since its introduction in 1845, it reproduced only identically, by vegetative reproduction (a bit like cuttings). It therefore changed little. Today, it is no longer the mildew of our grandparents! We are dealing with strains that have become very virulent. And the old varieties are totally available: put your great-grandfather driving your car and give him the instructions by mobile phone, you will see how the old ones "were better"!]

[stephgouv]

And so, the risk may become greater and greater that BB (for those who deal with it) is no longer effective on next generation mildew.
I think that next year, I will do like Doris: plant a mix of different varieties
And as Jeff would say: "you can have a bad year, but not fifteen!" (... immediately ^^)

[Moindreffor]

And so, the risk may become greater and greater that BB (for those who deal with it) is no longer effective on next generation mildew.
I think that next year, I will do like Doris: plant a mix of different varieties
And as Jeff would say: "you can have a bad year, but not fifteen!" (... immediately ^^)

as Didier says, there are several ways of fighting
chemistry, with Bordeaux mixture as an authorized "organic" treatment, but there is better for those who are not "afraid" of chemistry, even less aggressive treatments sodium bicarbonate or even potassium (which is better) because of the potassium), but here we need a rigorous follow-up and again we only brake

and the mechanics, the tunnel, which has its own limits, the condensations, and the humidity

we can cross the two

the use of modern varieties which are mainly hybrids and therefore non-reproducible means that it is necessary to buy new seeds every year, if this is the price to pay to guarantee a harvest each year, it is a calculation to be made where then plan the conservation over 2 years to allow yourself a year with few tomatoes

for me, next year it will be part of the sheltered tomato plants

[Did67]

And so, the risk may become greater and greater that BB (for those who deal with it) is no longer effective on next generation mildew.

No. BB has a very specific mechanism of action. Cu ions⁺⁺ (and not the metal copper! No need to put "copper rings" in the foot) act by various mechanisms. It "kills" the germ of the fungus filament from the top of the leaf (if it is present at germination!). Since it has been used, because of this multiplicity of "cell sites" in its action, it has never been bypassed ... Let's say that it is a poison large enough and sufficiently violent for the mildew to pass through it. !

On one condition, very often a little forgotten: the Cu ++ ion must be in place when the spore germinates on the leaf; it works before the filament enters the leaf ... So once you see the symptoms, its effectiveness is reduced to new infections. But the mildew, which has entered the plant, continues to weave its web (its hyphae) ...

When I speak of downy mildew which "cracks" the resistance of hybrids, it is genetic resistance introduced into the plant (resistance genes). This resistance is said to be "vertical": it is specific to the strain in question, reacting to it ... Even if this should not be confused, it "looks" like what happens in the case of viruses: an organism infected acquires a memory which allows him to react; but if the virus mutates, it "cracks" this defense. But beware: it is not a question of "vaccination" in tomatoes; just a genetically acquired reaction, which makes the infected cell hyper-sensitive, commits suicide and hyphae with ... End of the adventure. This therefore requires precise recognition, with rapid reaction. And this mechanism there, the mildew "cracks" when it recombines ...

[stephgouv]

Thank you for the explanations concerning the BB.
And for the Potassium Bicarbonate which is to be sprayed as soon as the first signs appear, how does it work?

[Biobomb]

Thank you for the explanations concerning the BB.
And for the Potassium Bicarbonate which is to be sprayed as soon as the first signs appear, how does it work?

I am very skeptical about the use of potassium by air. It can worsen, I have not been told, but I deduce when we understand how a leaf works.
I think it's the baking part that could heal.