Beneficial Insects Can Keep Pests Out of Farmers Fields

7 hours ago

A South Dakota State University graduate student is looking into insect-friendly field management practices that can save farmers money.

Instead of eliminating insects from crop acres, Alex Michels is researching farm practices that encourage them.

“For every 1700 insect species, there’s only one pest. Insects get a bad rap. And when you see some bad insect out in your field and you spray, that can kill all those other 1700 good insects as well,” says Michels.

When Michels refers to good insects, she’s talking about beneficial insects that work to pollinate plants or break down manure or eat weed seeds or aerate the soil or eat insects that can cause harm to crops like corn, soybeans, sunflowers or wheat.

A recent field study this South Dakota State University graduate student conducted looked at the effectiveness of predator insects.

“I did an experiment on some fields where I put a caterpillar larva out in the field and I pinned them to the ground so it couldn’t move. Then, I left it out there for an hour. I came back after an hour to check if the caterpillar was dead or alive, if it was eaten, and I found was I put 1,000 caterpillars out there and a third of them were gone within one hour. They were eaten by insects,” Michels says.

Alex Michel’s research also looks at regenerative farm practices, like no-till and cover crops that are known to entice beneficial insects, like those predator insects that ate the caterpillars. She then evaluates how much money farmers save through ecosystem services provided by beneficial insects. For example, when predator insects take care of a pest, then farmers don’t need to buy insecticide.

Michels’ hope is that by demonstrating the cost-savings connected to certain farming practices, more farmers will be motivated to implement practices that are not only friendly to beneficial insects but also reduce the need to apply pesticides.

“I think farmers have a big opportunity, they have so much land, they can impact so many acres by just small changes,” Michels says.

Michels’ research is funded through a grant with the Ecdysis Foundation. The data will be compiled and published when her thesis is complete early summer 2021.

If you’re wondering why beneficial insects prefer fields that have not been tilled or ones that have a diverse mix of plant species planted on them, Huron farmer Jeff Hemenway explains it this way.

“They need water and food and shade. And there’ not gonna go over into a field because its hot and dry and really, it’s kind of like a desert environment out in that field. But if you get into a no-till field and it has been that way for a long period of time, that whole environment changes and all of a sudden you end up with all this residue across the top of the field. Now ants go all the way across the field. Well ants are one of those predatory insects most people don’t think about. They’re a major predator out in the environment,” Hemenway says.

Hemenway hasn’t tilled his fields for more than 20 years. And a few years back, he experienced something similar to what Alex Michels saw in her caterpillar research.

“A flight of cutworms came in and not to explain in too great a detail, but you can actually see their eggs, they are bright orange and they were laid on the residue in the field. And because I’ve been in a diverse rotation and no-till for a long period of time, I’ve got a lot of beneficial insects across the field. I just wanted to see if they were gonna be a pest in the field. So, I went and flagged the area so I could tell where it was. And I kept scouting it and looking at the plants in that area. And you know, I can tell you, bottom line what happened. Nothing. Nothing happened because the insect populations are beneficial, actually killed the pest. Ate those eggs before it became a pest within the field,” Hemenway says.

And anytime his management practices entice nature to take care of a problem for him, Hemenway says it’s a win-win.

“As a farmer, I think one of the first things you want to do is, of course make money like anybody else. But at the same time, you know, it’s there’s a stewardship. In other words, there’s a responsibility for taking care of the environment that is the fields that you have,” Hemenway says.

Another reason Hemenway is slow to use pesticide, is in addition to crops, he is also a beekeeper. He got into bees after hearing a speaker share how the pollinator insect could help boost soybean yields.

“If you have a hive near a soybean field you can experience as much as 4 bushel per acre increase,” Hemenway says.

At the current market price of about $13.70 per bushel, an additional 4 bushels per acre increase can amount to quite a bit at harvest.