A Review of Biofungicides

Garth Conrad

There’s a relatively new class of fungicides that seemingly bridges the gap between traditional agrichemicals and organic approaches.

Biofungicides contain naturally occurring beneficial microorganisms, either bacteria or fungi –based, in concentrations that render them cost efficient and easy to apply using traditional agrichemical methods. They are EPA tested and registered for environmental and worker safety, and are proving themselves to be a solid first line of defense against pathogenic microorganisms that cause certain plant diseases.

The bacteria based fungicides are formulated with patented strains of bacteria, including Bacillus subtilis and Streptomyces lydicus. Organic practitioners will recognize many of these beneficial organisms. Common brand names include Rhapsody, Companion and Actinovate SP. The fungi-based products use Trichoderma, with trade names including PlantShield, RootShield and SoilGard.

Their benefits are numerous. Biofungicides have low or zero restricted-entry intervals (REIs), and are non-toxic for workers. They can have growth stimulant properties and are less phytotoxic than chemical fungicides, non-harmful to beneficial insects and resistance proof. Biofungicides are applied as a preventative measure before pathogenic diseases take hold, but some have curative abilities with early stage infections. They are applied as a soil additive, soil drench or now as a foliar spray. Their use targets pythium, phytophthora, fusarium, rhizoctonia, verticillium and other soil born bad guys and powdery mildew, bacterial spot, bortrytis, alternaria and other foliar diseases.

Growers see healthier growing environments, stronger plants, earlier finishes and greater plant development over time when using biofungicides. The recent additions of the foliar-based applications have great potential in the landscape maintenance arena.

Notice the use of patented strains of organisms. Now that’s a discussion. It’s interesting to note that the US only extended the right for other organisms to exist with the Endangered Species Act of 1973. This is my species, use with paid permission only? Where did we get the right to say what organism has the right to exist and who controls it? Bacterial genes spliced into plants (vegetarianism redefined), human genes spliced into animals (cannibalism anyone?), profiteering from new life forms? We have pollution, global warming and species eradication from the past ignorance of our endeavors. I think we need to think this issue through. When do we become indigenous and work with the rest of Nature?

[Back to Green Report]

Source: Nursery Management and Production magazine.