It seems there are ever increasing amounts of products for agricultural use that are considered “biologicals” in this rapidly advancing field of research and product development. Biological products can serve as natural pesticides and biostimulants that lead to growth enhancement, disease control, soil health improvement, and plant nutrient uptake enhancement, among numerous other uses.
According to R.J. Rant of Nutrilink Biosystems based in Michigan, biologicals are a diverse group of products derived from naturally occurring microorganisms, plant extracts, or other organic matter. They fall into two main categories: microbials (live organisms including bacteria, fungi, nematodes, protozoa and viruses) and biochemicals (naturally occurring compounds including plant and insect growth regulators, organic acids, plant extracts, minerals, and pheromones). Microbials are fairly well understood, but there is still much to learn about biochemicals, Rant said.
Biologicals that have been in use for a while in agriculture include: Bacillus thuringiensis (Bt), Bacillus subtilis, seaweed extract, humic and fulvic acid, sugar (molasses), compost teas, and fermentation extracts. These have significant value, but also limitations.
“With sugars, for example, we get biological stimulation but a little is great and too much is not necessarily a good thing. You have to be careful when you feed sugars to your plant on the soil because you feed everybody and you can get pest and disease issues,” Rant said. “Compost teas are really hard to duplicate and they can be very inconsistent and they are only good for six to 12 hours.”
Future agricultural applications of biologicals will include plant growth promoting rhizobacteria that can help control plant pathogens, enhance fertilizer efficiency, and degrade synthetic substances. In addition, biologicals can be used to address different types of resistance of pathogens or insects, Rant said.
As with all things, there are benefits and challenges with using biological products in agriculture. As pesticides, for example, biologicals can be very target specific with low impact on non-target organisms, a low risk of resistance and a low environmental impact.
“As pesticides are under more scrutiny, these products can be a real fit when or where we lose the use of chemicals,” Rant said. “The great thing about a biologicals is that there is no known resistance because they are such chemically and microbially diverse products.”
But, they are typically less effective than their chemical counterparts.
“When you are considering any of these biologicals, we feel they have 50% or 60% of the strength as the synthetic chemicals and a lot of growers have mixed results with them. They work in an integrated system. You need to have a good overall nutrition plan with good soil health. Then they can work as well as a lot of the top chemicals, but they can only work if there is good nutrition,” Rant said. “Biological products work best as a systems approach to an overall fertility soil management program. They need good fertility to work their best. And like with any chemical, they are often misused to address the wrong disease on the wrong crop or they are misplaced because people don’t know how to use them.”
Even with these shortcomings, Rant sees a very bright and beneficial future with biologicals.
“They really fit in down the road with nutrient efficiency utilization, which is a big one considering our phosphorus issues with Lake Erie. They are also really good as resistance management tools to rotate with chemistry to keep resistance management in check,” he said. “They can really stimulate soil biology as we advance into the soil health era of farming, especially where manure application is tricky from a regulatory standpoint. They can help feed the biology of your soil.”
A key to effective use of biologicals moving forward will be an understanding of what they can and cannot do.
“One problem with biologicals is that some people think that if they use a biological then they don’t need to buy nitrogen or plant protection,” Rant said. “They really aren’t meant to replace your fertility system or reduce your pesticide or fungicide use. They are more to make what you are already doing more efficient. It is usually around a 10% increase in efficiency.”
And in this age of increasing regulatory difficulties and costs, biologicals can have ample advantages.
“The big thing for companies from a regulatory process is that these are natural products and the burden of regulation is a little easier so these products can get to market and be very cost effective,” Rant said. “That will benefit the company, but also the grower.”
As biologicals become better understood, there will be more combinations in the future to address a wide array of challenges in very targeted ways
“Combinations can be powerful and you will start to see a lot of companies putting these things together because you get a well rounded product,” Rant said. “We are seeing what they can do for fertility and general disease suppression and biologicals are definitely here to stay.”