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BioBac-wettable powder

BioSol-solution

Biological Fungicide

Introduction

BioBac (wettable powder) or BioSol (liquid formulation) is made of a natural microorganism, Bacillus subtilis, isolated from soil in Taiwan.  The microorganism itself has the properties as a fungicide and can compete with agricultural pathogenic microorganisms. Additionally, the antagonistic biomaterials produced during the cultivation of this microorganism can prevent those pathogenic microorganisms from damaging crops.  Thus, the products have both preventive and remedial effects on crops.  Based on this natural microorganism, BioBac and BioSol are safe to use without toxicity to humans, mammals, fishes or honeybees.  Nor do they contaminate the environments.  When applied on crops to prevent or remedy diseases caused by pathogenic microorganisms, they can help in lowering the amount of chemical pesticides to be applied on the crops. Consequently, the impact of chemical pesticides on the environments can be reduced. This follows the worldwide trend.

The microorganism was fermented and formulated into wettable powder or liquid biofungicide containing 10⁹- 10¹⁰ CFU/g or CFU/mL.  The formulated products can be applied to soil or sprayed on leaves of crops.  The number of B. subtilis cells in the soil will increase after these products are applied, but it will maintain a steady state in a short while.  As a result, the microbial phase in the soil will be kept balanced without causing contamination and/or excessive and residual problems.

Properties

u          The sole, legal biofungicide ever developed in Taiwan.

u          Proved nontoxic by toxicological tests; therefore, no restrictions on applications prior to harvests.

u          Containing residual nutrients from fermentations which help the crops to thrive.

u          The sole pesticide suitable for organic culture and Good Agricultural Practices---People feel safe when applying it and need not worry about residual problems of agrochemicals.

Mode of Action

Several bacilli including Bacillus subtilis are antagonistic to plant pathogenic fungi and bacteria. B. subtilis produces many different bioactive materials and antibiotics, which hinder the propagation of pathogenic fungi.  Usually, a family of closely related bioactive peptides rather than a single substance is produced and most of the peptides are cyclic structures, which resist hydrolysis by enzymes. One group among the peptides is iturin.

The mechanisms by which antagonistic microorganisms affect pathogen population are not always completely understood, but they are generally attributed to one or more of four effects: (1) direct parasitism and death of the pathogen, (2) competition with the pathogen for food, (3) direct toxic effects on the pathogen by antibiotic substances released by the antagonist, and (4) indirect toxic effects on the pathogen by a volatile substance released by the metabolic activities of the antagonist. For iturin produced by B. subtilis, the antagonistic mechanism is relatively well-known. It is reported in the literature that this compound can react and form a complex with the sterol molecules on the cell membrane of the pathogen cells. The ion transport channels are enlarged as a result. In turn, the permeation property of the cell membrane is altered and potassium ion leaks rapidly. Consequently, the germination of pathogen spores or the propagation of the pathogen fungal mycelia is inhibited. Besides, when applied on crop leaves, on fruit surface or in soil, the fertile B. subtilis spores contained in BioBac and BioSol can compete with pathogenic fungi for room and resources. Since B. subtilis, belonging to the bacterial family, grows faster than pathogenic fungi, it consumes the nutrients in the local environments promptly. The growth of the pathogenic fungi is thus retarded.

Antagonistic effects

BioBac and BioSol have a broad range of fungicidal spectrum. They are effective against crop diseases caused by Alternaria, Botrytis, Collectorichum, Erysiphe, Fusarium, Mycosphaerella, Phoma, Phytophthora, Pythium, Rhizoctonia, Sclerotium, Sclerotinia, Uncinula, Xanthomonas, Xylaria, etc.

Application

The typical application of BioBac below was approved by the Agrochemicals Technical Consulting Committee of the Agriculture Council, Executive Yuan, Government of Taiwan.

BioBac and BioSol show excellent efficacy against crop pathogens. After diluted to 800-1000X, they can be sprayed evenly on branches and leaves where diseases just broke out. For soil-born diseases on roots and stems, a 600-800X dilution of BioBac or BioSol can be used to soak seeds or irrigate roots. These products can also be applied on fruits for post-harvest protection.

Notes

u          For best results, apply before the diseases break out. This reduces damages by the diseases and the amount of the fungicides to be applied. Cost is therefore brought down.

u          Store in a cool, dry and well-ventilated place and avoid direct sunlight.

u          Keep out of reach of children.

u          These microbial products are natural and nontoxic. People can apply them without worrying about problems associated with pesticide residues.

u          Dispose the empty packing materials in an incinerator or landfill approved for pesticide containers or bury them in a safe place.

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