Corn rootworm populations have exploded in recent years, which means more farmers than ever are asking how to get rid of the pest. Ron Roling is an AgriGold Agronomist from eastern Iowa, the self-proclaimed rootworm capital of the world.
“Yeah, I do believe it’s possible to maybe control rootworm better. Our populations do tend to increase over the past few years, but with different management practices and rotating traits, we found that we can do a good job of controlling rootworm in our fields.”
The first line of defense against corn rootworm is corn hybrid selection, and he shares some tips.
“Yes, I believe the best approach is that we still have to select hybrids that have strong roots. The analogy I give is you can’t have a poor rooted plant, put a trait on it, and expect to have better roots. You’re just protecting poor roots. So ideally, we like to select hybrids that we know are strong-rooted, put a good trait on them, and then use the management practices that are going to align with that hybrid and work best in your field.”
While it’s convenient to beetle bomb at the same time they’re spraying fungicide, Roling says that’s not the best timing.
“So remember, when most growers are doing their fungicide, a lot of them like to get started either right at VT tasseling or shortly thereafter. And, at that point, when beetles emerge, the males are going to be emerging first. Females generally do take two to three weeks later. So if we do it too early, it’s kind of like the analogy of deer hunting, and we’re just shooting the books, which isn’t going to help control your population. So ideally, we would like either to a, maybe time our fungicide application a little bit later when the females will emerge, or just understand that you may need a second application of insecticide to control the females later in the year.”
Roling says some fields are at higher risk of heavy corn rootworm pressure than others, so Roling wants farmers to closely monitor their fields.
“So any long-term corn-on-corn fields will certainly have more pressure naturally, but this year in particular, if there are any later-planted fields or maybe some replanted fields, remember that those fields will probably have the last green plants, in other words, the last viable food for the pests, so that’s where they’ll be attracted to at the end of the year, which then they will be laying their eggs and you’ll have more larvae pressure next year.”
For support implementing a systems-based approach to getting rid of corn rootworm, reach out to your local AgriGold agronomist.