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Implementing Biocontrol for Early Blight in Potatoes

Grant Recipient:

Northwest Coalition for Alternatives to Pesticides
PO Box 1393
Eugene , OR 97440-1393

Jennifer Miller, Sustainable Agriculture Coordinator
208-850-6504
jmiller@pesticide.org
Fax: 208-433-1827

Project Period:

March 1, 2009 – February 28, 2010

Principal Investigator:

Jennifer Miller

Downloads:

R10 2009-03 Final Report.pdf (4.65 MB)
R10 2009-03 IPR1.pdf (4.16 MB)
Miller Proposal.doc (109.5 KB)

Description
Idaho potato farmers often use three applications of fungicides each season to control early blight; a chronic disease in most of Idaho’s potato production. Growers are concerned about the development of resistance to these fungicides and need alternatives. This project will field demonstrate the use of a biological control for early blight in 2009 and expand grower adoption in 2010. Bacillus mycoides isolate “J” (BmJ) is a naturally occurring bacteria discovered by Dr. Barry Jacobsen at Montana State University and shown to control several plant diseases by eliciting a plant defense response. Montana Microbial Products tested BmJ for control of early blight in potatoes in research field trials in 2005, 2006, and 2007 with excellent results. The Northwest Coalition for Alternatives to Pesticides and Montana Microbial Products will work with 10 cooperating potato growers in 2009 to demonstrate BmJ under commercial conditions. The effectiveness and economics of this practice at the field scale will be compared to the growers’ normal early blight management practices. During summer 2009, 80 growers, crop consultants, and ag professionals will attend field days to learn about the use of biocontrol for early blight. In winter 2009/2010, an additional 300 growers will learn about this practice through workshops and technical bulletins. In 2010, the project will target 5,000 acres for treatment with BmJ for the control of early blight, resulting in a potential savings of up to 10,000 pounds of fungicides and provide growers with a new method for managing resistance.

Project goals and objectives
1) In summer 2009, ten Idaho potato growers will replace the use of 200 pounds of fungicides with the biopesticide BmJ for early blight in strip trials on 100 acres of potatoes.

2) As a result of educational outreach and technology transfer, 25 Idaho potato farmers will commit by February 2010 to using the biopesticide BmJ for early blight control on at least 5,000 acres of their 2010 potato crop. This will reduce fungicide use by 7,000 to 10,000 pounds, depending upon disease pressure.

3) In September and October 2009, the project team will harvest potatoes from the strips for quality and yield ratings on the ten growers’ fields. In December, we will review the results with the crop consultants and cooperating growers to determine effectiveness and seek commitment for using the practices in 2010.

4) University of Idaho research partners will conduct on-research station demonstrations of BmJ at the Twin Falls/Kimberly and Aberdeen stations. These demonstrations will be used in educational outreach.

5) Potato growers not directly involved in the demonstration trails will learn about BmJ for early blight control through two summer 2009 field days, three presentations at 2009/2010 winter workshops, and a publication mailed to 600 potato growers and agricultural professionals.

6) In summer 2009, determine whether the biopesticide can be applied to fields through an irrigation system via chemigation. Effectiveness will be determined by a trial conducted by Miller Research LLC.

Outcomes
1) In summer 2009, ten Idaho potato growers will replace the use of 200 pounds of fungicides with the biopesticide BmJ for early blight in strip trials on 100 acres of potatoes.
Ten farms were located across the major potato growing areas in southern Idaho, from Glenns Ferry in western Idaho to just north of Idaho Falls in eastern Idaho. These farms provided a variety of growing conditions, soil types, and early blight pressure. In addition, three of the participating farmers grew organic potatoes. We also worked with three crop consultants to regularly monitor the ten fields. Our crop consultants included Kelly Hurst of Blackfoot, ID, John Taberna, Jr. of Blackfoot, ID, and Jeff Miller of Rupert, ID. Their involvement was essential for the future adoption of the practice, as these crop consultants work with the majority of potato growers in Idaho.

We treated the strips in all ten fields from June through mid-August. Fields received one, two , or three applications of BmJ. The earliest maturing field in Glenns Ferry was first treated in June, whereas the other potato fields were first treated in July. In general, early blight pressure was low this season in Idaho. Some of the growers used the biopesticide as a standalone treatment, while others used BmJ as a resistance management tool in combination with their commonly used fungicides. A few of the fields in the Blackfoot area did show more severe early blight.

BmJ replaced the use of 77 pounds of fungicides on the 100 acres involved in this demonstration, including 64 pounds of older chemistries (chlorothalonil and mancozeb). This is less than we expected to replace, based upon the 2005 USDA NASS data for fungicide use in Idaho. The main reason this goal was not achieved is because the majority of the fields in the project did not experience typical early blight pressure, so growers used less fungicide than usual. Growers are also starting to use a newer product Endura (boscalid), as compared to the strobilurin class of fungicides (which have resistance issues) and the older chemistries (which have environmental concerns). This change in product selection also impacted the pounds of fungicides used. In addition, this project included three organic fields where no fungicides were used as the grower standard program on the remainder of the fields.

2) As a result of educational outreach and technology transfer, 25 Idaho potato farmers will commit by February 2010 to using the biopesticide BmJ For early blight control on at least 5,000 acres of their 2010 potato crop.
This objective was not met because of the impacts of the current economic situation on the ability of MMP to complete the full registration of BmJ and offer the product for commercial use in 2010. This objective has been postponed, and we expect to reach this goal in 2012. In 2010, we will work under the existing experimental use permit for BmJ with farmers on 100 acres of potatoes.

3) In September and October 2009, the project team will harvest potatoes from the strips for quality and yield ratings on the ten growers’ fields. In December, we will review the results with the crop consultants and cooperating growers to determine effectiveness and seek commitment for using the practices in 2010.
Yield data were collected from all fields, except for one field near Shoshone which did not show any early blight pressure. Yields were measured in hand dug sections of each strip in seven of the remaining nine demonstration fields. In the fields near Buhl and Rupert, we used mechanical harvesters to dig passes across each of the strips in the field. We met with the crop consultants and some of the cooperating growers in early December to review the results. Overall, yields were similar for the BmJ treated strips as compared to the grower standard. Details are in the attached BmJ WP 2009 Grower Trial Summary.

4) University of Idaho research partners will conduct on-research station demonstrations of BmJ at the Twin Falls/Kimberly and Aberdeen stations. These demonstrations will be used in educational outreach.
We coordinated with two University of Idaho plant pathologists to conduct research field studies. These trials were important in establishing the value of the biopesticide in resistance management, increasing the University of Idaho extension specialists’ experience with the microbial control, and enabling the researchers to include it as part of their early blight disease management recommendations. These trials were also another avenue to reach growers with the information, since the researchers share the results during field days and presentations.

5) Potato growers not directly involved in the demonstration trails will learn about BmJ for early blight control through two summer 2009 field days, three presentations at 2009/2010 winter workshops, and a publication mailed to 600 potato growers and agricultural professionals.
See outreach/deliverables. Since BmJ is not available for commercial production in 2010, we scaled back our plans for additional outreach through winter workshops and a technical bulletin.

6) In summer 2009, determine whether the biopesticide can be applied to fields through an irrigation system via chemigation. Effectiveness will be determined by a trial conducted by Miller Research LLC.
Miller Research conducted a research trial, where BmJ was applied through the irrigation system via chemigation versus ground application. There were no difficulties applying BmJ through the irrigation system via chemigation. This result shows that BmJ can be reliably applied via chemigation, which will increase growers’ ease in using the product.

Project Links
Not mentioned

American Farmland Trust