Beneficial Bacillus

As a grower you’re familiar with biologicals that contain a host of natural ingredients, including microscopic organisms. Often referred to as microbials, these microscopic organisms, which include fungi and bacteria, offer plants protection from disease, insects and weeds. They also offer a viable and sustainable alternative to chemicals that are increasingly becoming less effective as disease and insects acquire tolerance to them.

Perhaps one thing you didn’t know is not all microbials are alike. One microbial in particular, bacillus subtilis, a common and effective ingredient in fungicides, is an example of a strand of bacillus that varies in strength and effectiveness.

“It’s like saying, let’s go get a car, without specifying which one,” says Keith Giertych, of Growth Products, who sells a number of different products around the globe for use in horticultural and agricultural production.

While some bacillus have a sinister side to them, bacillus subtilis is one of the good guys. According to a Toxic Substances Control Act report from the Environmental Protection Agency, Bacillus subtilis “is considered a benign organism as it does not possess traits that cause disease. It is not considered pathogenic or toxigenic to humans, animals or plants. The potential risk associated with the use of this bacterium in fermentation facilities is low.”

Like a breeding program that produces a plant, such as a cucumber, with all the desirable traits a grower is looking for, the strength and efficacy of bacillus depends largely on how it is selected and colonized in the laboratory.
 

Understanding Bacillus

When you pick up a handful of soil you’re holding millions of these tiny microbes in the palm of your hand. Bacilli are like little workers in the soil, consuming the carbon in organic matter, which could include dead roots from sickly, or poor performing plants. The carbon is transformed into food — major and minor nutrients — for plants to utilize.

Bacillus is a bacterium that has a number of applications and cause and effects, some not so desirable to humans. Bacillus subtilis is used on agricultural seeds of vegetables, soybeans, cotton, and peanuts and flower and ornamental seeds. It is also used as a drench that will colonize and protect the root systems of plants. Finally, it is being used to produce insect toxins, including one to kill malarial mosquito larvae.

Different strains of the bacteria Bacillus perform different functions in the soil.

“For the plant, it’s kind of like a trip to a spa,” says Giertych. “The bacilli wants to pamper the plant, breaking down nutrients into usable form, guarding the roots, and producing antibodies. The reward for the bacilli is the ability to multiply in the soil as they feed off organic matter.” He says the more they multiply, the more they provide the marvelous benefits mentioned above.

Unlike chemicals that are used up in the soil and can potentially harm the environment, bacillus is like a gift that keeps giving. In addition to multiplying in the soil and colonizing around the roots of plants, bacillus mineralizes soil, breaks down organic matter so it is usable; chelates, phosphorous, iron, zinc, and some of the minor nutrients. Nitrogen is also more available when these microbes are in the soil.

Another nice thing about the bacillus subtilis that is found in today’s biologicals, they have a pretty long shelf life. Giertych says that Companion Biological Fungicide can be stored up to two years with no loss of spore life and up to 7 years while maintaining 96 percent spore life. There is no water in a container of Companion, the bacilli come to life when exposed to water and soil.
 

Bacillus offers alternative to chemicals

For growers, one problem with using chemicals is that plants and insects build up a resistance to them. New chemicals to handle the same problems are struggling to get approval from the EPA, not only here in the U.S., but abroad. People are turning more towards food that is locally sourced and organic, which is also driving the market for biologicals. And of course, chemicals are hard on the environment, particularly our fragile water resources, birds and fish.

From a grower’s standpoint, bacillus is a natural way to grow a healthy plant, whether it be in the greenhouse or in the field. Greenhouse growers have reported less root mass in cell packs when relying solely on synthetic fungicides. And of course, chemicals are expensive and don’t have as long lasting benefits as biologicals

Finally, chemical companies are having a tougher time coming up with new chemicals to replace or supplement the old chemicals that are becoming less effective due to plant resistance.

Neil Moran is a horticulturist and freelance writer based in Sault Ste. Marie, Mich.