Fall copper treatments

Copper: angel or demon?

Both of them. Interesting in some cases but with a poor environmental profile.

Very interesting for fighting against contaminations by fungal spores,

Copper is very toxic to these, bacteria and some viruses. After 2 hours’ contact of the spores with copper they no longer have the ability to germinate. It is when the leaves fall that the main contaminations occur.
Indeed, by falling the leaves leave a small scar on the twigs through which the fungus spores, bacteria and viruses intrude especially during wet periods.

Later (about 2 weeks later) these “doors” close and the plant is again protected.
It is also advised (copper) on wounds of size or accident.

But a poor eco-toxicological profile,

Because it behaves like a heavy metal it accumulates in the soil.
In addition, it is toxic to the liver.

So what to do?

Reserve him for jobs for which he has no replacements, such as fall salaries.
For the rest, try as much as possible to replace it with several strategies:

· Choice of plant varieties resistant to fungal diseases and bacteriosis (mildew, botrytis, anthracnose).

· Use cultivation techniques unfavorable to fungi (watering, aeration, choice of substrates).

Optimize the use of plant defense stimulators (bacteria, yeasts, fungi)

· Choose other active substances when they exist.

And in summer ?

The copper must imperatively be positioned at the right time and of course in the right place. In the right place thanks to modern and well-adjusted equipment and above all in the absence of wind in accordance with the law.
It should be sprayed exactly when the germination conditions of fungal spores, such as mildews, have the right conditions for germinating, high humidity (100%) with water in liquid form on the plants and temperature above 20 ° C.
That is to say that the treatment window is located in the hours following a thunderstorm, a rain, or even sometimes in the event of heavy dew.

Do not forget either that copper compounds are very easily washable, so they should not be used when there is a risk of rain for the next 6 hours.
In addition, copper being rough, it is poorly tolerated by sensitive plants or by tender leaves.
It is these constraints of use that lead to the preference for other products, in particular synthetic products during vegetation.

To note :

The use of plant defense stimulators such as brewer’s yeast, Saccharomyces cerivisae, the subtle bacillus, Bacillus subtilis, as well as other microorganisms that are not yet authorized for sale to hobbyists, reduces the use of copper and IFT, treatment frequency index, for professionals.
The use of copper is limited to 4 kg per hectare per year by the legislation currently in force.

In conclusion,

Cupric ion, which is found in the various cupric compounds (tribasic copper sulphate, Bordeaux mixture or copper oxides, copper hydroxides, potassium copper carbonate) is a very good substance active against bacteria and fungi but it is only effective in preventive use. It must therefore be applied at a specific time, immediately after the appearance of conditions favorable to contamination, after an injury, pruning or summer rain.

It is to be avoided in all other uses such as spring or winter treatments.

WARNING :

Copper is not an insecticide, it is totally ineffective against aphids, caterpillars or other animal pests.
What’s more, due to its toxicity, the operator and the slurry preparer must wear PPE, personal protective equipment, waterproof gloves, masks to A2P3 standards, boots and water-repellent suit or waterproof outfit.

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