The use of many chemical pesticides to control crop pests in recent times has brought great benefits to agricultural production and human life. However, chemical drugs are highly toxichas a huge impactto creatures.

Moreover, their persistence in the environment after a long period of use will lead to many negative consequences such as: pollution of the living environment, harmful to human health, destruction of many beneficial organisms, loss of natural ecological balance… In some cases, when using many chemical drugs, pests do not reduce but instead cause more harm by killing many natural enemies and making pests resistant to drugs.

To limit the use of chemical pesticides while still providing good pest control, there are two important measures: applying integrated pest management (IMP) and increasing the use of biological pesticides. Using biological pesticides is an important measure in the system of general biological control measures.

SoWhat are biological pesticides?What types of biological pesticides are available today? What is the mechanism of action of biological pesticides? Microbial product Duc Binhwill provide useful information to help readers better understand current biological pesticides.

1. What are biological pesticides?

Biological pesticides generally include preparations used to prevent microorganisms harmful to plant resources, and preparations that repel or attract harmful organisms to plants for destruction.

There are 2 types of biological pesticides: microbial pesticides and herbal pesticides

Organisms that damage plant resources (also known as pests) include: pests, diseases, weeds, rats and other harmful biological agents.These are organisms that are not beneficial to plants and must be eliminated.

Biological pesticides are made from two basic sources: from pest-killing microorganisms and extracted from natural herbal substances. Therefore, biological pesticides include two groups: microbial pesticides and herbal pesticides.

Microbial pesticides are biological pesticides created using biotechnology methods. Using effective microbial activity can inhibit and destroy disease-causing microorganisms (bacteria, fungi, viruses…). The most prominent is the microbial pesticide Bt (Bacillus thuringiensis). Bt grows and secretes a protein that is toxic only to plant pests.
Herbal pesticides (organic pesticides) are substances that have the ability to kill pests in the body of plants and herbs. Typically, synthetic chrysanthemum insecticides (Pyrethroids) are based on the structure of Pyrethrin found in the insecticidal chrysanthemum plant.

Biological pesticides play an increasingly important role and are widely used in agricultural production due to their many good characteristics.more superiorcompared to chemical drugs, especially for human health and the environment.

2. Advantages and disadvantages of biological pesticides

Speaking from a scientific research perspective, any product has its own advantages and disadvantages. Same with biological pesticides, there are advantages and disadvantages:

2.1. Advantages of biological pesticides

Replace chemical pesticides that are harmful to humans (pesticide residues) and the living environment.
Safe to use for human health and the environment.
Does not harm the effective microbial ecosystems of soil and plants. The effect of destroying pests is based on the mechanism of biological toxicity and the right target.
Shorten the quarantine time of agricultural products and food used.
Toxic residues on agricultural products are very few (almost non-existent).
Increase plant resistance.
Broad spectrum of action, long-lasting biological drug effect. Microbial pesticides have the ability to spread and survive on pests’ bodies for a long time. This is beneficial because it increases the number of parasitic enemies in the field, helping to limit pests.
Control many types of diseases for one type of crop.
Herbal pesticides are simple, easy to make, easy to find raw materials for production, and low cost.

2.2. Disadvantages of biological pesticides

In addition to outstanding advantages, biological pesticides also have some disadvantages:

Pest control effect is slow: after about 3-5 days of use, the drug will be clearly visible, especially for microbial pesticides: Bt, NPV virus and parasitic fungi. After entering the worm’s body, it takes some time for microorganisms to become active and produce toxins that cause disease in the worm or parasites that develop on the body later.
Short effective retention period: Most biopesticides are easily decomposed in the natural environment. This characteristic makes organic pesticides leave little residue on agricultural products. Bt and NPV virus preparations are sprayed in the cool of the afternoon so that at night the worms that crawl out to eat will be contaminated with the drug.
Strict storage conditions are required: because biological pesticides are easily affected by the natural environment, storage requirements are more stringent than chemical pesticides. Direct sunlight, heat or too much humidity all make the medicine less effective. In particular, Samonella bacteria preparations used to kill mice must be stored in cold conditions below 150C

In summary, compared to the advantages, the disadvantages of biological pesticides are small and can be easily overcome. It is enough that the user is knowledgeable and confident about the product.Especially knowing how to use the right productstechniques according to the characteristics of each drugOptimal efficiency is very high.

Using biological pesticides is a way to protect crops in the direction of sustainable organic agriculture

3. Biological pesticides

Based on the main ingredients in biological pesticides, biological pesticides can be divided into the following main groups:

Microbial pesticides
Toxins and antibiotics
Herbal pesticides
Other biological drugs

3.1 Microbial pesticides

The main ingredients of the drug are living microorganisms, which can be fungi, bacteria, viruses, and nematodes. The microorganisms in the preparation are mainly in dormant form as spores or cysts, which can withstand long-term unfavorable living conditions.

For microbial pesticides, microorganisms must live in dry or liquid conditions with additives. The shelf life to maintain effectiveness must not be too short, at least 6 months for convenience of preservation and use.

After use in the field under favorable conditions, microorganisms will grow and parasitize on suitable host bodies. Microorganisms in the product compete for living space and food, secreting antibiotics and toxins against fungal diseases and pests that damage plants.

Microbial pesticides are used very effectively, are a line of effective biological pesticides, and plant protection products of the biotechnology industry.

3.2 Toxins and antibiotics

Toxins and antibiotics are substances formed in microbial culture environments and are extracted to make biological pesticides. Temporarily, a toxin can be called a substance that is toxic to an organ or physiological function in an organism, in this case to pests (typically Avermectin).
Antibiotics are substances that affect the vital activities of pathogenic microbial cells (typically: Streptomycin, kasugamycin…).

3.3 Herbal pesticides

These are substances extracted from plant bodies, including vegetable oils. These are secondary organic substances made up of plant bodies, mainly Alkaloids and Phenols. They are substances with high biological activity, but in the plant body their physiological function is not great.

Among current biological pesticides, herbal medicines occupy an important position and are increasingly abundant due to their high effectiveness, abundant raw materials and relative ease of processing.

3.4 Other drugs of biological origin

Some pesticides have other biological origins such as: Chitosan from shrimp and crab shells, humic acid, fulvic acid from peat, hydrolyzed amino acids from protein… These substances are being researched and discovered, making the type of biological pesticides increasingly rich and diverse.

Currently, mineral oils are also used to prevent plant pests and diseases. Although not directly derived from organisms, mineral oil is a natural product and has many characteristics as a biological pesticide. In particular, mineral oil is highly safe for humans and the environment

In addition to the classification by ingredients, based on the control object, biological pesticides are divided into groups: insecticides, fungicides, rat poisons, snail repellents, and plant growth regulators.

4. Mechanism of action of biological pesticides

The use of biological pesticides has basically brought many benefits to plants. However, in terms of mechanism of action, this method has the following outstanding advantages:

4.1 Mode of action

The mode of action of biological pesticides is actually very diverse. The main methods are:

Pesticides such as Bt and NPV virus only work through toxicity
The parasitic fungi Beauveria and Metarhizium act through contact
Herbal pesticides and toxins act through both exposure and toxicity routes
In addition, herbal substances also have the ability to repel and lightly steam. The ability to internalize is very low, only the group of antibiotics that kill diseases can be absorbed into the plant.

The mechanism of action of biological pesticides is the effect on the nervous, respiratory and digestive systems of pests

4.2 Mechanism of action of biological pesticides

Biological pesticides mainly act on the nervous system. It also acts on the respiratory system (vegetable oils), digestive system (Bt pesticides), and repellent effects (herbal medicines, vegetable oils).
Insecticidal mushroom preparations live parasitically with nutrients in the worm’s body.
For biological fungicides, there are two main effects: antibiotics and stimulation of the disease resistance system in plants.
Antibiotics that prevent microorganisms that cause diseases in plants are relatively abundant such as: Streptomycin, Kasugamycin, Subtilis, Ningnamycin, Polyoxin, Tetramycin, Gentamycin, Validamycin…
Mechanisms that enhance the activity of the plant’s immune system are currently receiving strong attention. In plants, there is a system of enzymes (enzymes) that help plants resist pathogens.
The disease resistance system is one of the decisive factors for a plant’s life. Currently, there are many biological substances that act through this mechanism such as: humic acid, chitosan compounds, phenol, salicylic acid…
Biological drugs to control nematodes that cause plant diseases include Chitosan and Cytokinin. These substances have the effect of dispersing nematodes away from plant roots, limiting the growth and development of nematodes in the soil.
Herbal Saponin is used to kill yellow apple snails because it causes the loss of mucus in the mouth, the snail’s mouth hardens and cannot eat, so it dies.
Salmonella bacteria cause gastrointestinal disease in mice.

⫸ See more: What is GE? How to make GE water orchids, roses, and ornamental plants!

4.3 Effectiveness of prevention

Types of biological pesticidesThe effects on the nervous and respiratory systems are often quick and the worms die after a short time of exposure, similar to other chemical drugs, typically the Avermectin group and herbal drugs. Drugs that affect the digestive system (Bt bacteria) and parasitic fungi show effects more slowly, usually after a few days.

Regardless of the way and mechanism, in general, after only a few hours after the insect is infected with the drug, the insect shows signs of weakness, slow activity, and poor destructive power. Thus, the harmful effects are essentially limited, just wait a short time for the worms to die completely

Antibiotics show quick effectiveness. Drugs that act by stimulating the immune system often show slow and short-lasting effects and must be used early and continuously for many times to be effective.

The effective retention time of biological pesticides varies. Herbs, toxins and antibiotics are easily affected by environmental conditions, so their effectiveness is short. After spraying biological pesticides on plants under normal conditions, without being washed away by rain, these pesticides only remain effective in preventing pests for a maximum of no more than 12 hours. Their effectiveness is quick but also decreases quickly, so they need to be used at the right time.

Microbial pesticides (bacteria, fungi and viruses) have a long effective period if they meet appropriate environmental conditions. These microorganisms can even spread diseases to pests and continue to grow and accumulate in nature, contributing to limiting the harmful effects of pests over a long period of time.

The use of parasitic fungal products such as Beauveria, Metarhizium and Trichoderma mushrooms… increases the number of parasitic enemies, preserving the ecological balance of the field in a beneficial way.

Trichoderma biological productsIt is also an effective biological pesticide – antagonizing and destroying fungal diseases and nematodes

4.4 Drug resistance of pests

Pests’ habit of becoming drug-resistant is a natural phenomenon. Any type of pesticide, if used continuously for a long time, can cause pests to develop drug addiction and resistance. Drug resistance occurs quickly or slowly depending on the characteristics of the pest and the type of drug.

For pests that are accustomed to chemical pesticides, switching to biological pesticides significantly increases pesticide effectiveness. Many people in vegetable growing areas have also noted this through the use of Bt and Avermectin preparations to prevent silkworms.

Contact information

Microbial products Duc Binh – Center for research and application of biological productsspecializes in research, production and application of product lines: Probiotics, septic tank enzymes, wastewater treatment enzymes, aquatic enzymes, biological products…

Address:1B Alley 774 Kim Giang, Thanh Liet, Hanoi
Phone number: 0934.214.579
Hotline: 024.66.55.46.86

Buy/Zalo: 0934.214.579
Email:chephamvisanhungdung@gmail.com
Website:https://chephamvisinh.vn

⫸ See more:: 4 Ways to make herbal biological pesticides at home