Use bacteria to make pesticides

Using nearly 10 strains of Bacillus thuringiensis (Bt) isolated in Vietnam, experts from the Institute of Biotechnology (Vietnam Academy of Science and Technology) have researched and successfully produced high-efficiency Bt bio-pesticides. .

The outstanding advantage of these drugs compared to chemical pesticides is not to pollute the environment, not to kill useful and special insects that are not toxic to humans.

Bacillus thuringiensis bacteria
(Photo: ed.ac.uk)

They kill worms, green worms, cavities, lepidopteran worms, pine worms, rice leaf worms, and even nematodes harmful to coffee and pepper .

To produce Bt bio-pesticides, the research team led by Assoc. Prof. Dr. Ngo Dinh Binh chose Bt strains with high insecticidal activity.

These are strains that carry genes that produce toxin proteins.

When sprayed on leaves, toxin proteins in the form of crystals will kill certain pests.

Specifically, after pests eat poisonous crystals (pre-toxins), under the effect of a digestive enzyme in the intestinal fluid of the worm, pre-toxins are dissolved into small molecules with toxic activity. These toxins cling to the microvilli in the intestine, creating holes that allow water to flow in, make the water deep, stop eating and die.

The poisonous Bt crystals produced cannot be dissolved in human gastric juice, so Bt bio-pesticides are completely harmless to humans, as well as other organisms. The biggest drawback of Bt biocides is slow growth, 48 hours after eating the toxin, the worm dies.

According to Dr. Binh, each gene produces a toxin protein and that toxin destroys only a certain kind of worm. Therefore, to produce inoculants that kill a variety of worms, the team looked for genes to kill different types of worms, and then used transgenic techniques to introduce them to a Bt strain.

This strain is inoculated into a fermenting vessel, under suitable temperature conditions (28-30 degrees Celsius). After about 52-54 hours, it is possible to harvest the liquid containing the toxin protein crystals. If you want to spray immediately, just add some adhesives, anti-ultraviolet rays and surface tensioners . into liquid. If you want to create a powdered product, you have to make a plate, spray it, then add the stated substances and preservatives.

Test results in cabbage fields show that Bt preparations kill nearly 90% of pests, compared with nearly 80% of chemical drugs.

Currently the products are being used in areas of clean vegetables in Vinh Phuc, Thanh Tri, Hai Duong, Ha Tay, Dong Anh .

One life of vegetables needs to be sprayed 5 times, each time spraying must use 1.5kg of powder / ha with the price of 300,000-400,000 VND.

The team's desire is to produce this complete bio-pesticide Bt process applied on an industrial scale.

If produced at that scale, the price would fall to 1/10. In addition, the state should propagate, support and encourage farmers to use biological pesticides, reduce environmental pollution and protect people's health.