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ISA Research updates interactive economic decision-making tool

Article cover photo
The on-line decision-making tool, ISOFAST, continues to be updated with the most recent information and accurate data possible. Six soybean fungicide studies were recently added to the tool. (Photo: Joseph L. Murphy/Iowa Soybean Association)

By Peter Kyveryga, ISA analytics director and Suzanne Fey, ISA data analyst

For farmers interested in helpful information about products that could improve their profitability, the Iowa Soybean Association’s (ISA) “Interactive Summary of On-Farm Strip Trials” (ISOFAST) is an online tool designed specifically for them.

The ISOFAST tool is capable of providing visual summaries of tested products and practices, break-even economic analyses and summaries of key scouting, soil and tissue observations for tested treatments

The ISA Analytics team, partnered with the Iowa State University Agronomy Department, continues to refine and update the tool, so users have the most recent information and accurate data available. Recently, summaries of six soybean fungicide studies were added to ISOFAST, including Delaro, Domark, Headline & Lorsban (insecticide), Zolera Alpha Beta Pro, Zolera FX, and Regalia RX biological and fungicide. Farmers working with the On-Farm Network® tested these products, and most were applied at R2 or R3 growth stage.

Results from three of the studies revealed a combination of two or more fungicide classes are more likely to produce statistically significant and economic yield response compared with only one fungicide class or chemistry. This is critical to reduce future fungicide resistance. Also, a blanket fungicide application is not always warranted, weather and disease history should be considered in making fungicide decisions.

Details of fungicide studies

Last crop season, farmers tested Delaro, (Prothioconazole and Trifloxystrobin, QoI + DMI class), a systemic foliar fungicide (Figure 1). Delaro can control frog eye leaf spot, brown spot, charcoal rot and white mold. A significant yield response was found in five out of the six trials. The average yield response across all trials was 3.4 bushels per acre (bu/ac), with 90 percent chance the observed average will fall between 1.5 to 5.3 bu/ac. Field scouting did not reveal soybean disease pressure in 2018, with rainfall below normal for May and July, and above normal in June and August.

Using the figures in the ISOFAST tool of $9 per bushel soybeans and Delaro fungicide application at $20 an acre, the break-even yield response for Delaro is about 2.2 bu/ac. The probability to exceed the break-even cost is 85 percent and the average expected profit exceeding cost is $10.66/acre. Users can click the Economic Analysis button on the Trial Summaries & Economics tab to adjust for current market price and application costs.

Figure 1: Yield response summaries of six on-farm trials testing Delaro (Prothioconazole and Trifloxystrobin, QoI + DM class) fungicide on soybean in 2018. Economic analyses were based on $9 soybean and $20/acre fungicide and application cost.

Figure 2 shows summaries from 2016 testing Zolera FX (fluoxastrobin and tetraconazole (QoI DMI class) a systematic and curative fungicide. Zolera FX should control white mold and other soybean diseases. Rainfall in June was well below normal and above normal in July and August.

 Six of the seven trials had significant yield response. The average yield response across all trials was 1.2 bu/ac, with 90 percent chance the observed average will fall between 0.3 to 2 bu/ac. Field scouting did not reveal major soybean disease in 2016. The break-even yield response for this fungicide is about 2.2 bu/ac. The probability to exceed the break-even cost is only 3 percent.

Figure 2: Yield response summaries of seven on-farm trials testing Zolera (fluoxastrobin and tetraconazole, QoI DMI class) fungicide on soybean in 2016. Economic analyses were based on $9 soybean and $20/acre fungicide and application cost.

Figure 3 shows summaries from testing Domark (tetraconazole, DMI class, a preventative and curative fungicide). Domark should control frog eye leaf spot, brown spot, white mold and other diseases. Rainfall in 2008 was above-normal during the spring and early summer. Other than a relatively dry May, rainfall was fairly normal.

 Three of the seven trials had significant yield response. The average yield response across all trials was 1.2 bu/ac, with 90 percent chance the observed average will fall between 0 to 2.3 bu/ac. The break-even yield response for this fungicide is about 1.7 bu/ac. The probability to exceed the break-even cost is 23 percent.

Figure 3. Yield response summaries of seven of on-farm trials testing Donmark (tetraconazole, DMI class) fungicide on soybean in 2007, 2008 and 2009. Economic analyses were based on $9 soybean and $15/acre fungicide and application cost.

Although these foliar fungicide studies have been conducted in a limited number of locations, the data provides important information about which fungicide products or classes perform the best and may have less chance of developing fungicide resistance.

Visit the ISOFAST app on the ISA website to see results by rotation for all nitrogen trials.

Contact Peter Kyveryga at pkveryga@iasoybeans.com; and Suzanne Fey at sfey@iasoybeans.com.

For media inquiries, please contact Katie James, ISA Public Relations Manager at kjames@iasoybeans.com or Aaron Putze, ISA Communications Director at aputze@iasoybeans.com

For permission to republish articles or to request high-res photos contact Aaron Putze at aputze@iasoybeans.com. Iowa Soybean Association | 1255 SW Prairie Trail Pkwy | Ankeny | IA | 50023 | US

©2018 Iowa Soybean Association On-Farm Network®. All rights reserved. On-Farm Network® is a registered trademark of the Iowa Soybean Association, Ankeny, IA.Portions of some On-Farm Network trials are paid for in total or in part by the soybean checkoff.