Answers are from the Indiana certified crop adviser panel: Betsy Bower, Keystone Cooperative, Lafayette, Ind.; Jeff Nagel, Keystone Cooperative, Lafayette, Ind.; Marty Park, Gutwein Seed Service, Rensselaer, Ind.; and Dan Quinn, Purdue Extension corn specialist.

 

I have not seen root lodging from corn rootworms in years. I am going to go back to hybrids without rootworm protection to save on seed costs. Is that a sound move?

 

Bower: Do you live in an area where rootworm has been a problem in the previous 20 years in either second-year or first-year corn? There are certainly areas of Indiana where corn rootworm is not a problem and has never been much of a problem. But in the northern two-thirds of Indiana, there still is some risk of damage from corn rootworms, especially in second-year corn. I would certainly use corn rootworm protection in continuous cornfields.

 

Are you interested in using the latest high-yielding genetics or just saving money? In several cases, the hot, new genetics will include corn rootworm protection. The best hybrid genetics-wise and economic-wise still may be the hybrid with the corn rootworm protection.

 

Nagel: Overall, Indiana corn rootworm numbers have trended on the low side for several years. Many farm operations have moved away from traited corn with below-ground corn rootworm protection. While overall numbers are down, there can be geographical areas or fields with higher pressure. Corn after soybeans presents a lower-risk situation than corn after corn. Ideally, someone would have been in fields near or shortly after pollination to observe the relative abundance of corn rootworm beetles. Low levels of beetles lead to lower mating and egg laying.

 

If you’re growing corn after corn and you have no idea of rootworm pressure, consider having some level of rootworm protection. This could be through one of the trait technologies or even through applying liquid/dry soil-applied insecticide.

 

Park: In northwest Indiana, we still see some rootworm pressure, especially in corn on corn, and the pressure varies year to year. I know that other areas have very little pressure, and there is very little risk with moving away from the rootworm-protected hybrids. So, this decision is about managing risks if you are in an area that continues to have potential for rootworm damage. 

 

You can save some money, but if rootworms show up and chew on roots, there isn’t a product that you can apply to control them. So, you live with the damage. There is a chance that your favorite hybrids might only be available in a rootworm-traited version, and you might need to have the rootworm-traited hybrid to have tolerance to Liberty herbicide.  

 

Quinn: Indiana is at low levels for corn rootworm pressure. Therefore, this can be a viable option now. However, it is important to be mindful that this should only be done in fields that are rotated and not continuous corn. If you do make this move, continue to monitor for rootworms by adult sampling for beetles with sticky traps or digging roots to track pressure levels. It still can be risky to move away from hybrids without rootworm resistance, even if you have not seen any pressure in a long time.