ID card |
|
|---|---|
Scientific name |
Bacillus thuringiensis. |
Common name |
Bacillus of Thuringia. |
Classification |
Bacteria of the Bacillaceae family. |
Bacillus thuringiensis
was first discovered in 1901 by Shigetane Ishiwata, a Japanese biologist who was investigating the cause of the decimation of silkworms.
But it was not until 1911 and the German scientist Ernst Berliner that we obtained a more complete description of the bacteria.
Often referred to by its
acronym Bt
,
Bacillus thuringiensis
is found primarily at soil level, but also in water, air and plant foliage.
Through its selective action, this soil bacterium is an ally of choice in the differentiated management of your flowerbeds or your vegetable garden, because it only attacks pests, thus sparing valuable garden auxiliaries.
How does
Bacillus thuringiensis
work ?
When forming and releasing its spores (sporulation), the bacteria produces active proteins called
endotoxins
.
These have effects on certain insects such as:
Lepidoptera
(butterflies);
Diptera
(flies, mosquitoes);
Or even
beetles
(flea beetles, Colorado beetles, bruchids, beetles).
However,
Bacillus thuringiensis
does not directly attack adults, but rather
larvae.
Thus, endotoxins attach to the pest's intestines, causing their paralysis or the dissolution of their cells (lysis).
Once infected, the larva stops feeding and dies of starvation.
Bacillus thuringiensis attacks the larvae of certain pests: butterflies, flies, flea beetles, Colorado beetles, etc. Copyright (c) 2023 luchschenF/Shutterstock.
No use without permission.
Also read: Bordeaux mixture: everything you need to know to use it properly
When to use Thuringian bacillus?
Thanks to its entomotoxic properties, the bacteria has been used in biological control since the 1950s, mainly in vegetable gardens.
It is particularly effective against caterpillars and worms (box tree moth, pine processionary moth, olive tree moth, cutworm, etc.).
Certain strains such as
Bacillus thuringiensis israelensis
(Bti) are also used during mosquito control campaigns.
However, some studies tend to call into question the safety of Bti.
Although it is part of a biological and ecological fight,
Bacillus thuringiensis
must be
used with discernment.
Indeed, even if it is selective in its mode of action, it nevertheless attacks almost all caterpillars.
Remember that the latter turn out to be a necessary evil, because they are the origin of many butterflies which are useful to the garden for their role as pollinators.
Bacillus thuringiensis is even more effective if it is applied early and on young caterpillars.
Copyright (c) 2023 HenadziPechan/Shutterstock.
No use without permission.
Some precautions for use when applying
Bacillus thuringiensis
It is not because it is a biological treatment that precautions should not be taken before, during and after the application of the Thuringian bacillus.
A few simple rules can therefore be applied:
Don't wait until you're invaded to take action.
Bacillus thuringiensis
is even more effective if it is
applied early and on young caterpillars;
Conversely
, the endotoxin being destroyed by the action of the sun, the product has no preventive effect.
For this same reason, apply it either very early in the morning, or in the evening;
When preparing the porridge, follow the instructions and dosage indicated on the packaging.
More product does not mean more efficiency;
When applying,
remember to
protect
yourself by wearing the right equipment (gloves, boots, even overalls);
Do not spray
Bacillus thuringiensis
when the wind is
too strong;
If you are a parent and/or have pets, make sure that the treated area
is not accessible for a few days;
Target only infested plants.
There is no point in “contaminating” other plants by taking the risk of attacking auxiliary insects.