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 organisms such as nematodes, various microorganisms can also be used to combat diseases and pests in plant protection. Here are some examples:
Mushrooms that are used in biological plant protection and protect against harmful insects or other harmful fungi: Beauveria bassiana, which is a mushroom 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 fire blight and lodging rot in fruit cultivation.
Thirdly, the Ampelomyces quisqualis, which attacks the harmful fungus mildew and, penetrates its mycelium (branched fungal network) and feeds on it. Used against powdery mildew in strawberry cultivation.
Lastly, Clonostachys rosea (syn. Gliocladium catenulatum). Also feeds on the mycelium of other fungi and also strengthens plant growth. Used, for example, against gray mold in raspberry and strawberry cultivation.
Clonostachys rosea - fungal spores under the microscope
Fortunately, there's also the 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.
As well as the Bacillus amyloliquefaciens, which is used against harmful fungi in vegetable, strawberry, and wine cultivation.
Now, let's dive into the useful viruses as they have known and feared since the coronavirus pandemic at the latest. But here too there are 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.