We have been through a winter of extreme speculation, crisis-based scare tactics and a frenzy of fungicide product positioning concerning Asian soybean rust. MFA Incorporated has chosen to take a calm approach to this issue and is basing our core recommendations upon the combination of sound agronomics, product availability, fungicide mode of action, fungicide resistance and fungicide labeling.

Information concerning soybean rust is changing daily. The biology and occurrence of soybean rust have been well documented. I’ll not duplicate that information here.

As of early March, our rust management approach is based on several months of information collection and interpretation by MFA staff agronomist Lyndon Brush and me. Our recommendations have been designed toward what we believe is in the best agronomic and economic interest of our soybean producers. By press time or field season, some information may have changed. MFA’s network of certified crop advisers and crop protection product suppliers will be constantly updated if and when changes occur.

We recommend that soybean producers do not modify their preferred management practices such as row spacing, variety selection, planting date, weed control, etc., based on soybean rust. There is simply not enough North American information to draw upon to make those decisions. Currently, fungicides offer the only protection against soybean rust.

Listed in the table to the right are the four fungicide products currently labeled for use on soybeans. The first part of the table is the fungicides that have received or are pending EPA Section 18 emergency use labeling for soybean rust application in 2005. I have also listed the active ingredient and plant mobility for each product.

MFA has developed a four-scenario management recommendation program for soybean rust. Each scenario is based on monitoring rust’s winter survival in the gulf coast states and its northern movement toward the Midwest. We have developed a solid information exchange network with the USDA and university systems that will do most of the soybean rust monitoring throughout the South and the Midwest. We will keep MFA Agri Services and their soybean producers aware of rust activity.

Several “triggers” will be used in our soybean rust monitoring system. First, we will monitor soybean rust winter survival in Florida or Texas (currently no rust has been found in Texas). Second, we will monitor rust activity in, and movement through the Mid-South states of Georgia, Alabama, Mississippi, Louisiana, Tennessee and Arkansas. If rust is found in those states, then wide scale in-field monitoring will start in our region.

I have listed soybean rust scenarios to help plan your management of this disease for 2005. We feel they offer the best overall approach to soybean rust management in the Midwest. Our scenarios are based on the activity of each fungicide product combined with its labeling requirements. Review the listed Section 18 requirements/comments before planning your overall soybean rust management program.

Hopefully, this approach to soybean rust management will better prepare us for the 2005 field season. Please contact your MFA certified crop adviser for program planning and in-season management of this disease.

MFA soybean rust management scenarios and recommendations for 2005

Scenario 1: Rust either did not survive the winter in the gulf coast or has not moved northward into the Mid-South states.

MFA recommendation: Do not spray fungicides. Continue to monitor rust activity.

Scenario 2: Rust is expected or has been found in the region, but not yet present in your field.

MFA recommendation: Treat with full-labeled strobilurin fungicide. If second application is needed and rust is present in the field, then treat with Section 18 triazole product.

Scenario 3: If disease is expected, but not yet present and develops before/during initial treatment.

MFA recommendation: Treat with strobilurin + triazole. If second application is needed because disease is still present in the field, treat with Section 18 triazole product. If third application is needed, treat with another preventative like chloro-thalonil or strobilurin.

Scenario 4: If disease is established on site.

MFA recommendation: Treat with Section 18 triazole product. If second application is needed, treat with Section 18 triazole product if disease is still present or with a strobilurin product if disease pressure is minimum. If third application is needed, treat with chlorothalonil or strobilurin product if two applications of triazole or other Section 18 materials have already been applied.

Soybean rust Section 18 product use requirements and comments

Only two applications can be made during the growing season for any Section 18 or combination of Section 18 labeled products.

The Section 18 label must be in the possession of the user of these products at the time of application.

Section 18 labeled products are only to be used for the emergency described that justified the labeling request. Section 18 products are not to be used for non-emergency purposes. In the case of soybean rust, do not promote, sell or use Section 18 products for plant health purposes or the control of other foliar fungal diseases such as septoria brown spot, white mold or frogeye leaf spot.

There will be another round of products under review to receive Section 18 labels for soybean rust. MFA will keep you updated on this information.