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A Safe Way To Protect Crops

The World's First Lactobacillus Pesticide


The soil in both pictures contains a bacterial pathogen. The spinach sprouts in the top picture are growing from seeds that were soaked in liquefied lactobacillus, while the sprouts in the bottom picture come from untreated seeds. ©Kyoto Prefectural Institute of Agricultural Biotechnology

In recent years, both consumers and farmers have increasingly turned against the use of chemical pesticides out of awareness and concern about their safety and environmental impact. To address these concerns, Japanese researchers recently developed the world's first pesticides that use lactobacillus bacteria instead of harmful chemicals. This follows previous successes in developing pesticides that use microorganisms like Bacillus natto and soft rot bacteria.

How Lactobacillus Pesticide Works
The lactobacillus used in the pesticides is selected from among the various types of lactobacillus that can be extracted and collected from yogurt, pickles, and other fermented foods, with specific varieties being chosen to protect crops from specific diseases. For example, spinach wilt is an infectious soil-borne disease caused by Fusarium fungi. Previously, the only effective means of dealing with it was considered to be disinfecting the soil with chemical pesticides. Now, though, the bacteria Pediococcus pentosaceus KMC05 can be utilized to contain an outbreak. KMC05 can also be used against Phyophthora capsici, a soil-borne infection caused by Phytophthora pathogens.

Lactobacillus plantarum WKB10, meanwhile, is even more effective than commercial pesticides in eradicating Pythium, the cause of mizuna damping-off, outbreaks of which are believed to have increased as a result of repeated cropping and year-round cultivation in greenhouses.

As for other soil-borne infections, SOK04, another type of lactobacillus, can be used to combat soft rot in Chinese cabbage. These lactobacillus pesticides are as effective or even slightly more effective than Biokeeper water-dispersable powder, a previously developed microorganism-based pesticide, and these results have been confirmed in infected fields in five prefectures around Japan. Tests have proved that these pesticides are effective in eradication of diseases either when sprayed or when seeds are soaked in them.

Toward Commercialization
The immediate goal is to commercialize lactobacillus pesticide to combat soft rot in Chinese cabbage, with the aim being to register the pesticide, establish a manufacturing method, and release the product to market within the next few years. As work continues to select promising lactobacillus pesticides that can prevent and eradicate other plant diseases, researchers are also looking beyond fermented foods and are extracting and collecting other kinds of lactobacillus from wild and cultivated plants.

The development of these lactobacillus pesticides was spurred by the Kyoto Prefectural Institute of Agricultural Biotechnology, which presented an exhibit on how lactobacillus can be used to control spinach wilt disease at the Agribusiness Creation Fair sponsored by the Ministry of Agriculture, Forestry, and Fisheries. The institute then teamed up with Meiji Seika, a confectionery company with a track record in lactobacillus research and development, in a joint project with the aim of creating new pesticides. In order to commercialize these discoveries, it will be vital to shed light on the processes by which lactobacillus prevents disease. Kyoto Prefectural University is handling this task as the three parties continue their joint research. (July, 2008)