Corn farmers in Illinois face a common yield-robbing enemy: corn rootworm. Specifically, northern and western corn rootworm. Northern corn rootworm is a native to the area, while western corn rootworm spread from the west. The following is a history of these pests and the ways farmers have dealt with them.
THE EARLY YEARS
Native to the area, northern corn rootworm has challenged Illinois farmers for well over a century. Those same farmers began facing the additional threat of western corn rootworm as it moved across the Great Plains when continuous corn production became more common.
COMBATING THE PROBLEM
As corn production grew in the 1940s, so did the threat of corn rootworm. The first insecticides were used against them in the late 1940s, but by 1959 western corn rootworm was already resistant to a number of these insecticide options.
STAYING A STEP AHEAD
By 1965, Illinois farmers were primarily managing corn rootworm and the issues of resistance with crop rotation and soil insecticides. While practices evolved and changed over the decades, crop rotation and soil insecticides were still the primary management tools well into the 1980s.
A CHANGE IN BEETLE BEHAVIOR
As crop rotation continued to be a primary management practice, western corn rootworm beetles eventually adapted and changed their behavior. These corn rootworm variants began laying eggs in both corn and soybean fields. By the 1990s, there was a very large population of corn rootworm in Illinois and Indiana — causing devastating yield losses across the area.
As rotation-resistant beetle pressure increased, so did the need to monitor populations. Monitoring programs using sticky traps were developed, giving farmers — who now had to think about protecting both continuous and rotated corn — better guidance about whether they actually had a corn rootworm problem.
INNOVATIVE NEW TOOLS
At the turn of the century, corn farmers entered an era of trait innovations. After the first European corn borer traits were commercialized, it was recognized that this breakthrough could also be an ideal way to manage corn rootworm. In 2003, the first Bt products were introduced to manage corn rootworm, giving farmers a powerful new tool in combating this threat. At the start of the following decade, SmartStax® technology was introduced, helping farmers defend their corn from above- and below-ground pests.
A BRIGHT FUTURE
The adoption of Bt trait products like SmartStax® technology across the Corn Belt has played a key role in the decrease of corn rootworm populations. Illinois farmers remain vigilant in scouting though, and with the help of proven traited products and upcoming innovations like SmartStax® PRO technology, they have a clear advantage going forward in the fight against the billion-dollar bug, corn rootworm.