---
title: "Did my fungicide meet its yield guarantee?"
description: Find and analyze fungicide strip trials to evaluate a fungicide company's yield guarantee.
section: Do more
order: 20
---

***Problem:*** A farm sprayed Adastrio fungicide on its corn this year. Because the company that sold the fungicide provides a money-back guarantee that the treated acres yield an average of 3 bu/ac higher than the untreated acres, the farmer planted fungicide test strips throughout their field to test their claim. Now that it's the end of the year, the farmer wants to evaluate if the fungicide really did protect yield by 3 bu/ac. This tutorial finds the strip trials from operation data, evaluates the yield difference between treated and untreated acres, and then summarizes the results in a pdf report.

## 1. Find the trials

```prompt
Find all of my 2026 Adastrio strip trials and report the yield results.
```

```answer
I found 10 Adastrio trials on 9 corn fields. On most fields, one side got Adastrio + MasterLock and the other side has no recorded fungicide.

- Carrick has two trials. In the second, Adastrio went on top of two different at-plant treatments, so it has four sides.
- Hollis has no yield result, because its untreated area is only 0.1 acres.
- The largest difference is on Whitaker: the treated side yielded 239.1 bu/ac and the untreated side 185.0 bu/ac. But the untreated side is only 2.2 acres.
```
```note
**How Winnow finds trials**
- Winnow searches neighboring strips of a field that got different products or different varieties.
- It finds them automatically in your planting, application and harvest data. You don't need to set up a trial first.
- It defines a treatment in a trial as an area within 120 ft of another area with a different application or variety, and at least 120 ft from the headlands (field boundaries).
- A trial is defined as an area with at least 2 treatments with at least 1 acre to compare to each other.
```

## 2. Look at one trial on a map

Look at a trial on a map before you trust its result.

```prompt
Show me the Thatcher trial on a map, and the harvest colored by yield.
```

```answer
Here is the trial, with Adastrio in blue and untreated in red. Use the menu at the top to switch between the trial and the harvest.

![The Thatcher trial and its harvest, colored by yield](https://mywinnow.com/docs/images/fungicide-yield-guarantee/step-2@2x.webp)
```

## 3. Make the report

```prompt
The company guarantees that the treated acres average 3 bu/ac more than the untreated acres. Work out the yield difference for each trial, then average the differences weighted by the acres in each trial.

Make a PDF report. On the first page, show if the guarantee was met, the average difference and a table of the trials. Then give each trial a page with a map of the trial and a map of its harvest yield.
```

```answer
The treated acres yielded an average of 3.9 bu/ac more than the untreated acres, so the guarantee was met. I left out Hollis, because it has no yield result.

![Page 1 of the report: the result, and a table of the trials](https://mywinnow.com/docs/images/fungicide-yield-guarantee/step-3@2x.png)
```

```file
[Example report](https://mywinnow.com/docs/files/fungicide-yield-guarantee.pdf)
```

The AI writes its own report and draws its own maps, so your report will look different.

## 4. Ask more questions

Stay in the same chat to ask more questions, for example:

- "Is the guarantee still met without Whitaker?"
- "Was the untreated strip on Whitaker planted with the same hybrid as the treated side?"
- "Which corn varieties beat each other on my fields this year?"