Are You Using Biopesticides?

Some of the products farmers use to control insects and diseases on crops are made from naturally-occurring plant extracts, bacteria, and fungi. These types of products are referred to as biopesticides. Depending on what pest they control, the product may be referred to as a bioinsecticide, biomiticide, or biofungicide. Products that control mites may be listed as a bioinsecticide even though mites are not insects. Remember that all three categories are included in the umbrella term of biopesticides. Another way companies list them is biological insecticide or biological fungicide. To put it simply, some people call these products "biologicals." Some common examples of biological insecticides include Dipel (Bacillus thuringiensis subsp.), Neemix 4.5 (azadirachtin), and Pyganic EC 5.0 (pyrethrin). Examples of biological fungicides include Serenade (Bacillus subtilis), Howler (Pseudomonas spp.), and Rootshield WP (Trichoderma spp.). Many are OMRI-listed with approval for use in organic production, but not all.

Benefits and Drawbacks

Biopesticides are a great addition to your pesticide cabinet. If you are an organic grower, you’ve likely been using biological products from the beginning. Still, many conventional growers are aware of their usefulness and take advantage of the success of biologicals. In general, biopesticides are considered safer and have low pre-harvest intervals (PHI) and re-entry intervals (REI). The risk of disease or insect resistance is lower, and in some cases, they can improve the efficacy of other products. Biologicals are often classified as having multiple modes of action, giving them an advantage over a conventional pesticide that only works in one way.

Some examples of different modes of action include competition with pathogenic organisms, inducing plant defenses, causing mycoparasitism, and others. There are drawbacks to biological products. As a rule, biopesticides do not work well in environmental extremes or under high disease pressure. They are best used when pest pressure is low or as a preventative. Biologicals are not considered a cure for plant disease or a silver bullet to banish all insects. In most cases, the shelf life of biological products is shorter than conventional pesticides.

Too Good to Be True?

Sometimes when a new product comes out, the advertising and marketing sound wonderful. You may be tempted to make the investment and use the new product as a replacement for other products. Be careful! Set up a comparison on your farm. Use the new product in 1 row or a specific portion of a crop. Take notes about what you see. If the product shows promise, slowly integrate it with your existing products. Also, it is worthwhile to figure out how much the product costs per application and how many pathogens/insects may be managed.

Summary of a Recently Approved Biopesticide

Recently, I’ve read good things about Theia; a new biological fungicide recently approved for use in PA and a few other Mid-Atlantic states as of August 2022. Theia is a non-pathogenic bacteria called Bacillus subtilis subsp. that works in multiple modes of action. It is OMRI-listed and should be available for commercial purchase in late 2022. The label allows Theia to be used in the field or greenhouse. It is labeled for many crops, including small fruit, tree fruit, and vegetables. It has fungicidal and bactericidal properties against foliar and soil-borne plant diseases. The label states it should be used as a protectant and with a surfactant. It can be applied in almost any method, including bare root dip, tray drench, foliar spray, and through the irrigation system.

Throughout the product label, there are reminders for constant agitation to keep the product uniform while applying. The solution should not be left in the sprayer for more than 24 hours. The label directs users to have a spray solution pH of 4.5-8.5. A product sheet for Theia states that it is shelf-stable for two years. Researchers in Ohio, New York, and California have written reports on the use of Theia. Crops used in the research varied from cole crops to grapes to peppers, though Theia is labeled for many crops. Researchers in OH found Theia to reduce the incidence of black rot on cabbage significantly. In CA, grape researchers found Theia to be comparable with Quintec for powdery mildew control and superior to other biological products, i.e., Serenade and Double Nickel. Both examples included the use of a surfactant with Theia. If you want to try Theia or another new product on your farm, keep good records about the rate, surfactant used, and application method. Choose a portion of your field or greenhouse to trial the new product.

You are missing out if you rely solely on conventional chemical pesticides to keep diseases and insects at bay. I encourage you to add biopesticides to your spray cabinet. There are many options for bio-insecticides, -miticides, and -fungicides. Using products that work on multiple modes of action and act against resistance issues is a benefit you want on your farm.