Stacking the Deck Against Corn Pests
By Ryan Siefken, Agronomist

If you’ve had a chance to open up the 2008 Hoegemeyer seed guide, you will notice a wide variety of traits and trait combinations. You may ask: “Has technology gotten out of hand?” Our trait lineup has in fact grown from eight combinations last year to ten. This article will hopefully shed a little light on why we have chosen to offer all these different trait combinations.

Rootworm Tolerance
Of all the traits currently on the market, it seems that rootworm technology has gotten the most publicity lately. Probably the biggest reason is the dramatic rise in corn acres this past season (up 19% nationwide). Corn-on-corn is already a reality and is going to remain so in the foreseeable future. As a result, rootworm pressure will continue to be high. Demand for rootworm tolerant hybrids has increased due to the effectiveness and safety of the technology when compared to other forms of control.

So, rootworm resistant corn is important, but why does Hoegemeyer choose to offer three different types? There are four reasons.

First, because we are still independent, we have the option to work with all the major trait providers. Secondly, it is our position that all transgenic rootworm technologies offer excellent control of corn rootworm larvae. The third and fourth reasons will be explained after a quick rundown of the current rootworm traits that are on the market:

YieldGard® Plus: This was the first form of rootworm resistance brought into our lineup. YieldGard Plus is a rootworm resistant technology from Monsanto, and was incorporated into hybrids using their older gene gun method. This technology is still effective against rootworm larvae, but will slowly be phased out with the older genetics.
YieldGard® VT: VT stands for Vector Transformation technology. This is the new way that Monsanto inserts its rootworm gene into hybrids. This process uses the RR gene as a marker, making all VT hybrids resistant to Roundup® herbicide. VT technology has proven to be a more consistent way of incorporating rootworm traits into hybrids.
Herculex® XTRA: This is a Dow trait that utilizes two proteins for control of rootworm larvae. These hybrids also have the advantage of being stacked with Herculex® I above-ground insect protection, which has more comprehensive control of insects such as Western Bean Cutworm, Black Cutworm and Corn Earworm than the other Bts. All of our Herculex XTRA hybrids are also resistant to LIBERTY® herbicide.
AgrisureTM RW: Although this trait is not currently in our lineup, it is worth mentioning because the event has recently received full export approval by Japan. This will allow grain from these hybrids to be handled the same as all other rootworm resistant hybrids. We are currently testing these hybrids in our research plots.

This leads to our third reason, which is genetic diversity. If we only sold one family of traits, it would greatly limit the genetic pool that Hoegemeyer customers could plant on their farms. Every year, Mother Nature challenges hybrids in many more ways than just one or two traits can stand up to. Yield, standability, disease resistance and drydown are all important reasons for selecting a hybrid in addition to insect and herbicide tolerance.

The final reason is that the different technologies allow for flexibility in herbicide programs. While Roundup is currently the most favored form of weed control in corn, extensive use of only one mode of action means that weed resistance is inevitable. Liberty herbicide offers a way to break up this cycle while providing excellent weed control and crop safety.

Corn Borer Tolerance
You may have noticed that corn borer tolerance like YieldGard and Herculex is increasingly being stacked directly with rootworm tolerant hybrids. This is the case with 9668HxXTRA and 5353VTRR. The reason is that genetics get turned over so rapidly, and technology companies need to stack traits early in the development of elite hybrids in order to get the full offering of traits to producers’ fields. There will be situations when a farmer chooses to plant a Bt/rootworm tolerant hybrid on soybean ground because the hybrid simply has the right genetics. In these cases, having the rootworm gene certainly won’t hurt performance, but may also protect against problems such as rootworm variants or larvae that have survived the rotation for some other reason.

Herbicide Tolerance
You will also notice that we have some hybrids tolerant to both Roundup and LIBERTY herbicides. This permits growers to take advantage of the insect control offered by Herculex and Herculex XTRA, while allowing the use of Roundup for weed control. Another niche for these hybrids is where a field being sprayed by LIBERTY borders a field sprayed by Roundup. Drift and sprayer overlap are not a problem with a RR/LL hybrid. Finally, refuge acres come into play, making our RR-only and LL-only hybrids continue to be very important.

In summary, when deciding which hybrids to choose for the coming year, consider all aspects. Let the traits, agronomics, weigh wagons, yield monitors, and, of course, value, help you decide.