Bacillus thuringiensis

Bacillus thuringiensis biological larvicide

Bacillus thuringiensis, in the organic garden only products of organic or natural origin should be used, avoiding toxic pesticides, harmful to the environment and to those who will then eat the vegetables grown. Among the organic insecticides, a very interesting product is bacillus thuringiensis.

It is a specific product against some types of parasites, in particular, it is effective for fighting moth caterpillars that devour leafy vegetables, such as cabbage. The fact of hitting specific classes of insects is a great advantage of this insecticide. In fact, Bacillus thuringiensis is highly selective: it allows us to defend vegetables without hitting other insects that are useful in the garden, for example, bees.

Bacillus is a bacterium that affects the digestive system of the insect, there are several strains that can be useful against various parasites. The most used in the vegetable garden is the Kurstaki variety bacillus thuringiensis, which is suitable for targeting the aforementioned moth larvae.

The insecticidal action

Baciullus thuringiensis is a bacterium, single-celled organism. Its peculiar characteristic is that it is sporogenous: in certain external conditions, the bacterium forms a spore to its whole and frees it. In this way, the bacillus takes on a more resistant shape.

Together with the spore, a crystal is released, the latter having an insecticidal action: when ingested by insect larvae it becomes a toxin and blocks the digestive system, causing the caterpillar to die.

There are three main strains of the bacterium:

  • Kurstaki
  • Tenebronis
  • Isralelensis.

The different strains of Bacillus thuringiensis have efficacy on different types of insects and therefore different uses in the vegetable garden and organic garden, as we will see below.

Among the various organic insecticides this bacterium is particularly valuable due to its selectivity, in fact, it does not create problems for pollinating insects or ladybugs.

Natural non-toxic insecticide

Being an entomopathogenic bacterium, this insecticide is completely natural, and for this reason, it is a treatment allowed in organic farming, which does not lead to toxicity problems or environmental consequences.

Unlike most of the pesticides on the market, Bacillus thuringiensis does not harm humans, fauna, and, as already mentioned, even beneficial insects. Garden friends such as ladybugs, which eat parasites, or bees, which pollinate flowers, can rest assured.

The kurstaki variety bacterium works by blocking the digestive system of lepidopteran larvae (butterflies and moths), killing these insects by paralysis. For this reason, it can be used in organic horticulture without particular concerns.

Strains of bacillus thuringiensis

There are several strains of this particular spore-forming bacterium species.

The most interesting in organic farming among the types of Bacillus thuringiensis is undoubtedly the BTK (Bacillus Thuringiensis Kurstaki) because it is the one that affects the larvae of most of the harmful insects for the vegetable garden, for fruit plants, and for the garden. . Its effectiveness is mainly against lepidoptera, such as cabbage, borer, moth, moth, processionary. Nocturnes such as cabbage caterpillars are widespread on vegetable plants, while borers and moths are pests that often affect the orchard.

The tenebronis strain, on the other hand, is effective against young beetles, the most important application of this bacterium is the fight against the Colorado potato beetle, an insect sadly known to those who grow solanaceous plants.

Also of note is Bacillus thuringiensis israelensis because it is capable of hitting mosquito larvae. It is mainly used in water-soluble tablets, useful for reclaiming stagnant water. This larvicide is perfect if there are rainwater collection bins near the crops, which could otherwise become tiger mosquito breeding grounds.

How to use bacillus thuringiensis

In the presence of nocturnal or agrotid attacks, bacillus thuringiensis can be distributed on plants, the spores must be diluted in an aqueous solution. For better effectiveness, the treatment must be done in the evening, as the larvae come out at night to attack the vegetables. In addition, the spores of this insecticide are not very resistant, in particular, the heat and light can make the product harmless, hence the advice to do evening treatments.

Bacillus is not effective simply by contact: it must be ingested, and it affects only the larvae, it is not useful against eggs and adult individuals. This is why it is important to treat at the right time, in order to kill the generation of parasites before they can develop. On the other hand, other products are used against adult insects in organic farming, such as neem oil and pyrethrum, the latter must be careful because it is not selective, and although of natural origin it is toxic to many organisms.

Where to find bacillus thuringiensis

Bacillus thuringiensis-based insecticides are found commercially, usually in water-soluble granule forms. In these cases, use it will be enough to dissolve the insecticide in water and use it, but on the packaging of each product, you can find more information on its method of use and also on the doses.

Unfortunately, chemical insecticides are too often recommended in agricultural centers and gardening shops and it is not always easy to find Bacillus thuringiensis, even if it is a very useful product in the garden. Fortunately, today you can buy this excellent remedy online quickly and safely.


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