Microorganisms in biocontrol

Microorganisms are microscopic organisms that cannot be seen with the naked eye. Microorganisms include fungi, bacteria, viruses, and also some algae.

In addition to the use of beneficial macroorganisms such as nematodes, various microorganisms can also be used to combat diseases and pests in plant protection. Here are some examples:

Beneficial fungi
Fungi that are used in biological plant protection and protect against harmful insects or other harmful fungi:

Beauveria bassiana, which is a fungi that grows into harmful insects with its network and kills them. Used in fruit cultivation against the cherry fruit fly.

Aureobasidium pullulans. This is a yeast that forms a protective shield on the plant, preventing other harmful fungi from infecting the plant. For use, for example, against Erwinia and storage rot in fruit cultivation.

Ampelomyces quisqualis, which attacks the harmful fungus mildew,  penetrates its mycelium (branched fungal network) and feeds on it. Used against powdery mildew in strawberry cultivation.

Clonostachys rosea (syn. Gliocladium catenulatum). Feeds on the mycelium of other fungi too and also strengthens plant growth. Used, for example, against gray mold in raspberry and strawberry cultivation.

Beneficial bacteria
Fortunately, there are also beneficial bacteria. Most people know bacteria as pathogens. However, some can attack insects and harmful fungi in biological plant protection and are harmless to people, animals, and the environment.

Examples of useful bacteria are:
Bacillus thuringiensis, which has been used in fruit and wine growing since 1938 against harmful caterpillars of various butterfly species.

Bacillus amyloliquefaciens, which is used against harmful fungi in vegetable, strawberry, and wine cultivation.

Beneficial viruses
Viruses have been known and feared at least since the coronavirus pandemic. However, there are also useful species that protect our plants from harmful insects, for example. An example is the Cydia pomonella granulosis virus. It is used to protect apple trees in orchards from codling moth larvae.