Common broad spectrum fungal diseases in greenhouses and flower cultivation include powdery mildew, gray mold, blight, damping-off, root rot, leaf spot, etc. These diseases can cause harm to a variety of flower plants, affecting their growth and ornamental value. Since biological fungicides mainly rely on microorganisms and their metabolites, they have less impact on the environment and human health and are not likely to cause the development of drug resistance. They are more durable and effective in use and are widely accepted by people. Common biofungicide for plants include biofungicide Trichoderma, Bacillus subtilis, biofungicide mycorrhizae, etc.
1. Trichoderma
Trichoderma inhibits the growth, reproduction and infection of pathogens by producing small molecule antibiotics and large molecule antimicrobial proteins or cell wall degrading enzymes; and through rapid growth and reproduction, it seizes water and nutrients, occupies space, consumes oxygen, etc., thereby weakening and eliminating the gray mold pathogens in the same habitat; Trichoderma can also form pythium in a specific environment, which has a heavy parasitic effect on gray mold pathogens and inhibits the appearance of symptoms of grape gray mold.
Trichoderma harzianum is a species used in Trichoderma. It grows rapidly in the rhizosphere and phyllosphere of plants, seizes the sites on the surface of the plant body, forms a protective cover, prevents pathogenic fungi from contacting the plant root system and leaf surface, thereby protecting the plant roots and leaves from the above pathogens and ensuring the healthy growth of the plants. It also has the heavy parasitic and antibiotic effects of general Trichoderma. As a biocontrol fungus, Trichoderma harzianum can be used to prevent plant diseases caused by pathogens such as Pythium, Rhizoctonia solani, Fusarium, Rhizoctonia nigra, Columnar spores, Sclerotinia, and Sclerotinia sclerotiorum.
In addition to Trichoderma harzianum, Trichoderma asperellum and Trichoderma viride are also common Trichoderma.
Trichoderma asperellum, a saprophytic filamentous fungus widely found in soil, rhizosphere, phyllosphere, seeds and bulbs, has high universality and wide temperature adaptability. Its strong biocontrol ability and biostimulant function make it show significant advantages in plant nutrition, stress resistance and biological control.
Trichoderma viride is well known for its highly active ingredient. This enzyme has excellent degradation effect on crops. At the same time, it is also a rich antagonistic microbial resource with dual functions of protection and treatment, which can effectively prevent and control soil-borne diseases.
2. Pseudomonas Fluorescens
Pseudomonas fluorescens can first colonize in the rhizosphere or root surface of crops, and then rely on the siderophore or antibiotics produced to work; it mainly competes for iron ions – producing siderophores to complex root iron ions, so that the pathogens cannot get enough iron nutrition, thereby affecting the growth of various pathogenic fungi and reducing the harm to plants; it can also produce a variety of antibiotics, which have a strong killing effect on pathogens.
3. Bacillus Subtilis
Bacillus subtilis inhibits bacteria mainly through competition: it rapidly and massively reproduces and colonizes in the rhizosphere, body surface or body and soil of plants, effectively excluding, preventing and interfering with the colonization and infection of pathogenic microorganisms on plants, thereby achieving the effect of inhibiting bacteria and preventing diseases. Secondly, Bacillus subtilis can produce a variety of substances with antibacterial and bacteriolytic effects during its growth, thereby inhibiting the growth and reproduction of pathogens, and even destroying the bacterial structure and killing pathogens.
Bacillus subtilis mainly targets diseases such as cucumber powdery mildew, strawberry powdery mildew and gray mold, Chinese cabbage soft rot, citrus canker, rice blast, etc. It can also be used to regulate plant growth, induce plant resistance, and play a role in enhancing immunity and promoting growth.
4. Bacillus Velezensis
In recent years, research on Bacillus Velezensis has mainly focused on the fields of feed, medicine, textiles, aquaculture, sewage treatment, and plant protection. As a new type of biocontrol microbial factor, Bacillus Velezensis has attracted much attention in plant disease prevention and control, and promoting plant growth.
Bacillus Velezensis can effectively inhibit a variety of plant pathogens, such as Phytophthora capsici, Fusarium solani, Fusarium oxysporum, Rhizoctonia solani, and several pathogenic fungi on leafy vegetables, including brown spot fungus, stem spot mildew, Botrytis cinerea var. dianthus, and Sclerotinia sclerotiorum, and effectively prevent and control a variety of plant diseases.