New rootworm trait offers options for farmers

MONMOUTH, Ill. — VT4PRO isn’t a customized corn hybrid. But it acts like one.

“This is a nice option for those low pressure areas, where we still want rootworm protection, but we don’t need SmartStax PRO,” said Rachel Willis, a DEKALB Asgrow technical agronomist for central Illinois.

The new VT4PRO with RNAi technology combines above- and below-ground protection for growers who have some pressure from corn rootworms, but who don’t need the full spectrum coverage of SmartStax PRO.

With the rollout of VT4PRO, growers can customize corn rootworm coverage to their farms.

“The trait decision can be really complex. At the end of the day, it’s really nice to have options and it’s another option for us,” Willis said.

The territory she covers in central Illinois tends to have less rootworm pressure than areas further north.

“We have some rootworm pressure, but we don’t struggle like northern Illinois or northern Iowa, where there is really, really heavy pressure,” she said.

For growers who might be using SmartStax and a corn/soybean rotation to manage corn rootworm pressure, Willis said she sees VT4PRO as an ideal new option.

“Where I see this fitting really well is for those growers who are using SmartStax on a rotated acre,” Willis said.

“They want some protection, but they don’t have heavy corn rootworm pressure. This is another option and it unlocks high-yielding genetics for us.”

VT4PRO removes Herculex and adds the Cry3Bb1 protein. The combination of RNAi technology and the Cry3Bb1 protein provide two modes of below-ground corn rootworm control. Above ground, the Trecepta technology adds a third mode of action.

“From an above-ground standpoint, VT4PRO has an advantage as far as modes of action for above-ground control. You get additional earworm control, if you are worried about earworm. You get some cutworm control, as well,” Willis said.

For growers using cover crops, VT4PRO can add insurance against pest concerns that can accompany cover crops.

“We have more and more people trying cover crops and cover crops can lead to a higher incidence of secondary pests,” Willis said.

“Having the VT4PRO with the Trecepta technology and that additional mode of action above ground can be a nice fit and a nice fit following a cover crop, too.”

Agronomists, like Willis, have promoted best management practices for controlling corn rootworm, including implementing a rotation.

Willis said that while numbers of corn rootworm dropped off a few years ago, the pests, whose larvae feed on the roots of corn, have made a comeback.

“Prior to becoming an agronomist, I was in Bayer as a field researcher. I did a lot of rootworm trials. There were a few years where it felt like all we did was live and breathe root digs and digging and reading roots. It did feel like that pressure slowed down a little bit,” Willis said.

“In 2021, we had a lot of rootworm feeding. I do think my counterparts, like Jim Donnelly in northern Illinois, and other agronomists in those areas where we had heavy, heavy pressure did a nice job of talking about best management practices, including rotating to soybeans.”

After the surge of corn rootworm in 2021, Willis said promoting those best management practices appeared to have paid off in 2022.

“In 2022, it didn’t feel like we had as much pressure because we did a better job of talking about best management practices, whether it’s controlling adults at the right time, rotating to soybeans, and using SmartStax PRO, which came out in 2022,” she said.

“I think because of all of that, we haven’t heard quite as much about corn rootworm because growers have done a nice job of implementing those best management practices.”

Willis said she welcomes having another option to offer growers who have concerns about corn rootworm, but not the intense pressure.

“We put a lot of SmartStax PRO on rotated acres because some of us, in the back of our mind, remember rootworm disasters. So, we use that to guard against having some of those disasters,” she said.

“Using VT4PRO, where you’ve been using SmartStax, on a rotated acre, is a way to open up and get a different trait in there with new genetics.”

Willis still recommends SmartStax PRO as the best product on areas where corn rootworm pressure is heavy.

“I would say if you are in northwest Illinois, where it is corn after corn, SmartStax PRO is probably your best option there because it has the most modes of action for below-ground control,” she said.

“In my geography, I have a lot more 50/50, there are a lot more rotated acres. That is where I think it is going to be a really good option, on those rotated acres or those low to no pressure acres is really where I would like to see VT4PRO placed.”