We have completed replicated field experiments at seven research farms near Crawfordsville, Nashua, Kanawha, Sutherland, Armstrong, McNay, and Ames. We evaluated 20 fungicide and fungicide and insecticide combinations in four locations (Ames, Kanawha, McNay and Nashua) and 16 treatments in the other three locations. We have collected data on foliar diseases severity, aerial images, weather information and yields. We are still analyzing data; however, from preliminary analysis we see only very small positive yield responses of fungicide application. Once data analysis is complete we will deliver the result of this study through talks, publications, interviews and media releases. The result will help to
1. Identify predictive weather conditions that may help identify if/when to spray fungicides.
2. Refine fungicide recommendations through small plot and on-farm research.
3. Present information about fungicides through the ISU ICM News, newsletters and Extension presentations.
We have been screening for fungicide resistance but no isolate resistant to fungicide has been detected from Iowa yet.

Objective 1:
We completed field experiments at seven ISU research farms. Two soybean cultivars, a MG III for the southern locations and a MG II for the northern locations were planted. Foliar fungicides were evaluated at each farm for a total of 20 treatments in four locations and 16 treatments in three locations. We have collected data on foliar diseases, yield (bushels per acre), and weather data. Yield ranged from 57.6 to 98.5 bu/A. We will have a more complete report when all data are analyzed.

Objective 2:
We have collected leaves from fungicide trials across the state (both small plot and on-farm) that exhibit foliar diseases such as frogeye leaf spot and Septoria brown spot after an application of fungicide. Fungal isolation is on process. We will isolate these pathogens and send to Dr. Carl Bradley at the University of Kentucky. We are also working with the Plant and Insect Diagnostic Clinic to build up our capacity to screen for fungicide resistance in Iowa.

Objective 3:
Experiment 1 - Evaluate how early season applications affect root growth and yield: We have multiple application of Priaxor starting from R1 to R5 in the field experiments. We have measured plant growth, health, yield and moisture data. Data are being analyzed. We will also compare data across U.S. states who did a similar study.

Experiment 2 – Imagery and sensors and fungicide response: We collected aerial images at different times during the season to see how this information relates to yield responses to fungicides. We also collected leaf wetness and disease severity. Data analysis is on progress.

Experiment 3 - Investigate how leaf wetness and other weather factors affect yield response to foliar fungicides: To determine how weather variables predict positive yield responses in soybean as a result of a fungicide application, we established one field experiment with cultivar Pioneer 92Y53 (susceptible to frogeye leaf spot). There was a total of seven treatments, including 1) non-treated control; 2) foliar applications of Priaxor® R2 through R7. Plots were laid out in a randomized complete block design with six replications. Results from our 2014 experiment showed that RH>85% was a good predictor of leaf wetness.

We also purchased an additional nine WatchDog 2000 Series Plant Disease Stations and placed them near farmers’ fields that are for Objective 3, Experiment 2. Ultimately, we aim to identify predictive weather conditions that may help identify if/when to spray fungicides. We have collected data on weather information (Relative humidity; Temperature from two stations placed over grass next to the field); Foliar disease severity: All foliar diseases present will be assessed at R2 and R7; and at the end of the season: Yield; Moisture; Seed size; Dry matter accumulation. Data analysis is on progress.

Objective 4:
We completed a summary of soybean fungicides for Plant Management Network. Also, several winter meetings included information about our fungicide data in the talk. We also had talks specifically about fungicide resistance. And we wrote the background information about fungicide resistance for the ISU Resistance Management Workshop in January. Several field days, newsletter articles, and media interviews included information about fungicides.