ISA Research updates interactive economic decision-making tool10/01/2019 | Crop Production Research, Economics
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 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 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.
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.
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©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.