A newcomer in the fight against mildew

What is this product?

It’s about potassium phosphonate, a fairly simple product that has been known for many years. The phosphonate family is already used in food.
Potassium phosphonate is a salt. It has been approved as a phytoproduct since 2019. It is a biocontrol product that became available to amateur gardeners at the end of 2021. This biocontrol label means that it is not very dangerous for health and that it has a low impact on the environment.
Not to be confused with phosphates which are fertilizers.

What is it used for?

In foliar spraying, mainly against mildew but also against other plant diseases such as phytophtora (root fungus) which cause great damage in gardens.

How does it work ?

It is very interesting because it is first considered a stimulator of natural defenses, but it also has a toxic effect on parasitic fungi and has a systemic effect (penetrates into the plant).

His main interest?

It is an alternative to copper. It does not accumulate in soils for long, but does not become a fertilizer. It is not very dangerous for aquatic organisms and is not very toxic against certain auxiliaries, mainly useful mites for which Bordeaux mixture is deleterious.
It can be used 3 times a year and the gap between two uses is at least 10 days.

His flaw?

Its degradation produces phosphates, but used at less than 2 g per liter (dosage of the product sold commercially), this is a negligible aspect.

Finally,

This new weapon for amateur gardeners is added to those already authorized:

· The Bacillus subtilis str. QST 713, used against bacteriosis, botrytis, powdery mildew, fire blight, scab, moniliosis.
· The Bacillus amyloliquefaciens ssp. Plantarum strain D747, can be used against gray rot, sclerotiniosis, moniliosis, Oidium, fire blight.
And yeast Saccharomyces cerivisae. Recognized as useful against: gray rot, sclerotiniosis, moniliosis.
· Potassium bicarbonatecan be used against powdery mildew, scab and gray rot.

Let’s hope that the distributing firms won’t take too long to put other biocontrol products on the market because they are now numerous and are all eligible for use in amateur gardens.

Ask all your questions during the gardening program on Sunday morning on France bleu Isère from 9 a.m. to 10 a.m. by calling 04 76 46 45 45.