March 29, 2024

Resistance hot topic at 2017 Iowa Soybean Association conference

Resistance was a common topic at this year’s ISA Research Conference. From the ripped-from-the-headlines subject of weed resistance to revisiting the decades-old issue of soybean cyst nematode resistance, keeping pests at bay was of interest to farmer-attendees.

“While planning the conference, resistance kept coming up as a topic farmers were interested in,” said Keegan Kult, conference program coordinator and Iowa Soybean Association environmental scientist. “Weed resistance was the most prevalent, but there are so many other kinds of resistance farmers need to be aware of before it starts to affect their bottom line.”

With this in mind, the conference featured a mega-issue discussion on weed resistance, a presentation on SCN resistance and a pest resistance panel with speakers talking about weed, insecticide and fungicide resistance. The goal of these sessions was to provide farmers with the latest tips and information to improve their decision-making. While ISA has recently covered SCN resistance and weed resistance in their various publications, the topics of insecticide resistance and fungicide resistance were novel to the conference.

According to Iowa State University’s Erin Hodgson — one of the panelists — insecticide resistance is inevitable.

“Expect to delay, not prevent resistance,” Hodgson said. “Insects are made to overcome resistance.”

Insects may start with the advantage, but Hodgson made recommendations for farmers looking to have the last laugh.

Hodgson’s tips to avoid insecticide resistance:

• Change up insecticides — Not just brands, modes of action and chemistries need to change as well

• Try foliar insecticides — No documented resistance in Iowa Host plant resistance — Pyramided rag genes are awesome

• Post-spray scouting — It is important to ensure your insecticide is working

• Scout regularly throughout the season and be proactive

Another panel topic, fungicide resistance, caught some attendees by surprise. While not widespread in Iowa, (yet), a perfect environment is being created for fungicide resistance according to Syngenta’s Mike Leetch. During his talk, Leetch stated only three common fungicides are used in Iowa, not the chemical diversity needed to prevent resistance.

Leetch offered tips to avoid fungicide resistance:

• Use a fungicide with multiple modes of action — Don’t use the same fungicide, mode of action or chemistry repeatedly on the same field

• Follow the fungicide’s label for recommended rate — Using a fungicide at a low rate, usually due to cost, is the fastest way to build up resistance

• Apply fungicides before infection levels are high — By the time the plants show visible damage, it may already be too late

• Scout regularly throughout the season — The easy button is gone. Farming in regards to pest management is more difficult and complicated. Farmers are going to have to be better informed.

The main message from all the presenters was farmers need to be vigilant with their integrated pest management strategies by rotating chemistries, modes of action and most of all, scouting their fields for any sign of resistance.

To learn about opportunities ISA has to test pest management products and practices on your operation, contact your regional agronomist.