AMBOY, Ind. — For corn growers, rootworms are a problem. But how much of a problem they are — and how often — depends on where you farm.
Those two factors also can present a challenge for growers when they are selecting their corn hybrids for the next growing season.
The introduction of VT4PRO dual mode rootworm product will help make that decision easier.
“It’s been one of those things where we know where these heat maps are when we collect the beetle traps in July. It’s tough to know exactly if you are going to have the pressures or not,” said Jason Harmon, DEKALB Asgrow technical agronomist for northern Indiana.
Harmon said he is excited for the limited introduction of VT4PRO. The new corn rootworm trait combines two below-ground modes of action — the RNAi technology and the Cry3Bb1 protein — and above-ground control with Trecepta technology.
“It is built for areas like Indiana. We have corn rootworm pressures every year. It’s just that we don’t have that pressure to the extent where we know it will be high pressure every year,” Harmon said.
He said the need for different levels of control varies with the planting and management systems.
“If you are corn-on-corn, for insurance, we better go with the below- and above-ground protection to make sure you have control. If you are on a rotated acre, we are not seeing the pressure heavy enough that we should be worried, so I think we should go with the above-ground-only protection products,” he said.
Harmon said VTPRO4 offers total control of rootworms, including the above-ground package with Trecepta technology, to offer growers, no matter what their management system is for corn, peace of mind for any level of rootworm pressure.
“Now we have this trait addition with the VT4PRO, we have a great opportunity to have the superior above-ground control. We are putting the Trecepta above ground, which will give us the best mode of action there, and then these two modes below ground,” he said.
“You have a really good defensive product that is going to be beneficial for the guys who are somewhat concerned.”
Harmon said there are some areas where corn rootworm pressure tends to be heavier.
“My areas of concern are right along the Illinois state line. That is where we consistently do see corn rootworm pressures,” he said.
“We also are seeing, on the eastern side of Indiana, there are some populations getting larger. It’s kind of coming from Ohio, where they are corn-on-corn for silage.”
Harmon said for those growers who face heavy and consistent corn rootworm pressure, SmartStax PRO remains a top product.
“Our SmartStax PRO is the knock-dead for those corn rootworm larvae with three modes of action below ground. It really gives a positive feeling that you have total control for corn rootworm,” he said.
For 2024, VT4PRO will be sold on a limited basis.
“It is a limited launch. For my area, we have a 102, a 106 and a 114 that we are looking at,” Harmon said.
The new VTPRO4 varieties were showing their value in plots in 2023.
“I am really excited about the new 114-day DEKALB 1499. It looked really good in our plot sets and I am really happy to have a new 102 day, that also looked great, to add to our DEKALB portfolio for 2024. They add some of that diversity and give us some power with some nice new traits,” Harmon said.
Total control of corn rootworms is a priority — so is yield, and Harmon said VT4PRO doesn’t back down when it comes to bringing the bushels.
“You are going to have the protection that you want so you can sleep at night. Growers also can be confident that they are getting the DEKALB genetics backed with high performance. They do have the Roundup Ready post opportunity for weed control, as well,” he said.
Harmon said the use of the RNAi technology offers a new way of going after corn rootworm larvae.
“It’s not as fast acting as the Cry3Bb1 Bt protein that has been so good for us. It’s going a totally separate way of infecting these corn rootworm larvae and killing them,” he said.
“If we don’t mow them right back with that Bt protein, the RNAi technology is going to come in and make sure we clean house and get no resistance. That is a really cool thing, two different ways of going at these larvae.”