Agricultural landscape of crop fields

(Photo: Joseph L. Murphy/Iowa Soybean Association)

Utilizing historical fungicide and insecticide trial data for decision making

April 9, 2021 | Anthony Martin


Using historical data from 2013 to 2016, this video summarizes fungicide and fungicide/insecticide combined application data collected through on-farm trials. Utilizing this historical dataset, an online tool to aid in pesticide decision-making will be discussed. 

As soybean prices increase, foliar fungicide and pesticide applications may seem more financially feasible. But the decision-making process on whether to apply is different for every farmer.

One of the core considerations is whether the application is going to be economically justified. Other considerations include resistance potential, yield response, etc.

This video summarizes fungicide and fungicide/ insecticide combined application data collected through on-farm trials from 2013 to 2016.

Utilizing this historical dataset, ISA Field Services Manager Anthony Martin shows how an online tool Interactive Summaries of On-Farm Strip Trials (ISOFAST) tool can aid in pesticide decision-making.

The video explores 24, 3-treatment trials conducted throughout Iowa from 2013-2016. The treatments used in the trials include: fungicide (Priaxor) application, fungicide and insect application (Priaxor + Fastac) versus an untreated control.


  • Fungicide application alone resulted in a yield response increase of added 2 bushels per acre (1.75 to 2.5 additional bushels per acre)
  • Combined application resulted in a significant yield response in approximately 50% of the trials (13 of 24 trial locations)
  • Combined application averaged a 3.2 bushels per acre yield response.

Trial results show combining the applications can be advantageous, but Martin says farmers should consider the following:

  • Timely field scouting is necessary to determine application needs.
  • Unneeded, insurance applications of both chemicals increase the risk of resistance development.
  • If yearly applications are determined necessary, rotate modes of action to promote product effectiveness.

“This tool isn’t meant to be the end all, be all,” Martin says. “It’s simply a tool for economical decision making.