There is growing interest in new chemistries that are reduced risk or certified organic in fruit crop production in Wisconsin. Several newly registered products are available for disease control and will be covered in this article. Before we jump into the details of the products it is important that we first define the different categories they fall under. There are many terms that can be confused with one another when we talk about different types of fungicides – “reduced risk” “soft chemistries” “OMRI” “biopesticide” “biocontrol” – let’s start by clarifying these terms.

Conventional Pesticides: As defined by the Environmental Protection Agency (EPA), conventional pesticides are “all active ingredients other than biological pesticides and antimicrobial pesticides.” They are the most widely used pesticides in conventional production systems.

Reduced Risk: Products that are defined as reduced risk are determined by the EPA which reviews the “conventional pesticides that pose less risk to human health and the environment than existing conventional alternatives.” More about the EPA’s Conventional Reduced Risk Pesticide Program can be found here. It is important to emphasize that reduced risk does not necessarily mean that a product is certified for organic production, many of these chemistries are still considered conventional pesticides.

“Soft” Chemistries: This term typically refers to chemistries that are biologicals or natural products. The word “soft” is used to convey the idea that the chemistries are not as harmful as conventional pesticides.

OMRI (Organic Materials Review Institute): OMRI Listed products are permitted for use in certified organic operations under the USDA National Organic Program. Products that are OMRI certified will have this visible on their label. To read more about the OMRI visit their website where you can also access a listing of all OMRI approved products.

Biopesticide: As defined by the EPA, “certain types of pesticide derived from such natural materials as animals, plants, bacteria, and certain minerals.” Biopesticides are further divided into 3 distinct classes:

• Biochemical: biopesticides that control pests by non-toxic mechanisms, an example of this are sex pheromones which may interfere with insect mating.
• Microbial (often called “biocontrols”): contain a microorganism (e.g. fungus, bacterium, virus, protozoan) as the active ingredient.
• Plant-incorporated protectants: products that come from inserting genetic material (i.e. genes) into plants.

Remember, bio-, reduced risk-, OMRI- pesticides are still pesticides, and must always be used in accordance with the label instructions.

So, what are the benefits of bio-fungicides compared to conventional fungicides?

• Generally, less toxic to animals and the environment
• Limited off-target impacts; there is no broad-spectrum activity (as seen with some conventional fungicides) that may impact birds, mammals, or insects
• Reduce pollution because products decompose more quickly
• Can be used in IPM programming to help cut back on conventional pesticide usage
• Reduce the risk of fungicide resistance development

What are some of the disadvantages of bio-fungicides?

• Some may have a slower rate of control and lower efficacy compared to conventional products
• The shorter persistence of many bio-fungicides requires well-timed and frequent applications to achieve good disease control
• Bio-fungicides, especially those formulated from microorganisms, are susceptible to environmental conditions

—Recent Products for Disease Control in Grape and/or Tree Fruit—

*Mention of a product is not a recommendation or endorsement. The products listed below are newly registered and therefore little efficacy data has been reported. Further trial data will be necessary before making recommendations for control.

Howler

Howler is a new biopesticide product on the market. Target diseases for this product include Botrytis, powdery mildew, downy mildew, and black rot of grapes. Since this is a new product there is limited field efficacy data available.

• Registered for use on: Grapes, Strawberries, Apples, other fruit crops (see label)
• Manufacturer: AgBiome
• Active ingredient: Pseudomonas chlororaphis strain AFS009 (bacterium)
• OMRI Listed
• See label for application method and rate
• Do not apply by aerial application
• Pre-harvest Interval (PHI): 0 days

Oxidate 2.0

Research trials on grape in New York state found that Oxidate was effective for sour rot control. Oxidate is also labeled for fire blight control in apples. Field trials on apple in Michigan have demonstrated its ability to kill the fire blight bacterium, however due to the oxidizing effects of this product it can also kill plant tissues such as flowers, but this can be beneficial if flower thinning is needed.

• Registered for use on: Apples, Grapes, other fruit crops (see label)
• Manufacturer: BioSafe Systems
• Active ingredient(s): Hydrogen Peroxide and Peroxyacetic Acid
• OMRI Listed
• Pre-harvest Interval (PHI): 0 days

Romeo (Systemic Resistance Inducer)

In 2020, Romeo, a new preventative bio-fungicide from Wilbur Ellis was registered for use in Wisconsin on several fruit crops for control of downy mildew, powdery mildew, and several other diseases. Since this is a new product there is limited field efficacy data available.

• Registered for use on: Grapes, Apples, other fruit crops (see label)
• Manufacturer: Wilbur Ellis
• Active ingredient: Cerevisane (cell walls of Saccharomyces cerevisiae strain LAS117)
• OMRI Listed
• Pre-harvest Interval (PHI): 0 days

Stargus

A new bio-fungicide product was recently registered in Wisconsin for control of several fungal diseases of grape including downy mildew, Botrytis, and black rot. Since this is a new product there is limited field efficacy data available.

• Registered for use on: Grapes, Apple, other fruit crops (see label)
• Manufacturer: Marrone Bio Innovations
• Active ingredient: Bacillus amyloliquefaciens strain F727
• OMRI Listed
• Pre-harvest Interval (PHI): 0 days

Excalia

A new conventional fungicide, Excalia, was registered this year in Wisconsin for use in apples targeting apple scab, powdery mildew, and the juniper rusts. Trials in New York state suggest that Excalia provides good protection against apple scab.

• Registered for use on: Apple
• Manufacturer: Valent
• Active ingredient: Inpyrfluxam (FRAC 7)
• Pre-harvest Interval (PHI): Do not apply after petal fall.
• See label for restrictions

As more information becomes available about these and other fungicides for disease control in fruit crops, information will be made available on the Wisconsin Fruit News website.

This article was posted in Disease and tagged biocontrol, biopesticide, disease, disease control, Fungicides, Grapes, Leslie Holland, OMRI, reduced risk, soft chemistries, tree fruit.