Preparation method of high-content dry Bacillus thuringiensis suspension

Abstract

The invention relates to a high-content dry Bacillus thuringiensis suspension and a preparation method thereof. The preparation method comprises the following steps: concentrating a Bacillus thuringiensis fermentation liquid to a solid content of 18-25%, uniformly mixing the obtained Bacillus thuringiensis fermentation liquid concentrate containing 50-80% of a solid material, 1.5-8% of a dispersant, 1-7% of a wetting agent and 5-15% of a disintegrating agent (and / or a filler) in a stirring tank, grinding and homogenizing by a sand mill to obtain a Bacillus thuringiensis slurry with a solid content of 24-35%, pressing the slurry into a spray granulator through a peristaltic pump, granulating at a hot wind inlet temperature of 150-180DEG C and a tail gas outlet temperature of 55-70DEG C to obtain a product with a water content of about 3%, screening to obtain the 50-80% dry Bacillus thuringiensis suspension. The product has a particle size of 30-100 meshes, is fluffy, has a suspension rate of above 88%, a dispersibility of above 80%, and is easy to disintegrate and disperse. A detection result shows that the virulence titer can reach above 64000IU / mg. The dry Bacillus thuringiensis suspension has the advantages of one-step granulation, low production cost, high suspension rate, good dispersibility, and no nozzle blocking, is an ideal biological medicine for preventing and treating resistant Lepidoptera pests, and is in favor of the food safety.

Description

technical field [0001] The invention relates to a preparation method of a high-content bacillus thuringiensis dry suspension. Background technique [0002] In recent years, the occurrence of resistant lepidopteran pests such as diamondback moth, Spodoptera litura and Beet Spodoptera has become more and more serious, and chemical pesticides are currently the most important measures to control these pests. The high-intensity use of chemical pesticides has exacerbated the development of pesticide resistance of such pests, increased the cost and difficulty of pest control, and also led to serious food and environmental pesticide residues, and the rate of pesticide residues exceeding the standard in vegetables remains high. Therefore, it is imperative to develop environmentally friendly formulations of biopesticides. [0003] Bacillus thuringiensis is a Gram-positive soil bacterium with endophytic spores. It can form insecticidal crystal proteins in the early stage of spore form...

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Problems solved by technology

However, only a small number of chemical pesticide varieties are processed into this dosage form in China, and microbial live bacteria pesticides have not yet been processed into dry suspension concentrates by spray granulation.

[0006] In recent years, my country has also developed Bacillus thuringiensis water-dispersible granules, but the processing technology of this water-dispersible granules is extrusion granulation. Since Bacillus thuringiensis is a live bacterial preparation fermented from agricultural and sideline products, the sugar content High, easy to bond together, but the use of extrusion granulation increases the bonding strength, the product is not easy to disintegrate in water, the dispersibility and suspension rate are low, only suitable for low content (≤30%) thuringiensis The preparation of Bacillus thuringiensis water-dispersible granules is not suitable for the preparation of high-content (≥50%) Bacillus thuringiensis water-dispersible granules

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