Have you already ditched your heavy winter jacket? Have you noticed signs of spring?

A warmer-than-average winter begs the question: What will pest pressure be like this year?

“Predicting pest pressure is so hard,” says Kelly Estes, agricultural pest survey coordinator. “And it’s a question that everyone is asking because we have had such a mild winter.”

It’s a concern based on sound reasoning: Pests generally have better survivability rates in milder winters, which lead to more intense spring insect pressure, she notes.  

Here are the top four pests on Estes’ radar this year:

1. Western corn rootworm. “The pest everyone wants to know about is western corn rootworm,” Estes says. Population counts from the previous year factor into the equation because corn rootworms overwinter. The good news? Corn rootworm populations tabulated in the statewide corn and soybean survey were low. Spring rain events also impact corn rootworm populations. “Corn rootworms don’t swim,” she notes.    

2. Japanese beetles. Estes says Japanese beetles will likely overwinter without a solid freeze line in the soil. Japanese beetle populations were extremely high last season, especially in western and northern Illinois. “Survivability will be high, so there’s a good chance that populations will be high again,” Estes notes.

3. Black cutworm. Estes explains that black cutworms do not overwinter; they migrate on warm spring winds from the South. Estes says black cutworms migrated like never before in 2016. “Last year’s populations were the highest I’ve seen,” she says. “There was also the greatest number of significant flights.” Eight or more black cutworm moths over two days is considered a significant flight, Estes explains. Another warm spring with winds from the South could lead to another challenging year with black cutworm.

4. Brown marmorated stink bug.  “In my opinion, this is going to be a very interesting pest,” Estes says. Brown marmorated stink bug is a topic at all her winter meetings because it attacks several crops and plants: soybeans, corn, vegetables, fruits, ornamental trees and shrubs. “Populations are building across the state, including urban areas and small, rural towns,” she notes. “I get 20 emails or calls a week on stink bug reports.” As populations build, more injuries occur. Estes is confident the stink bug will move from the orchards it’s already impacting to crops like soybeans and corn. Brown marmorated stink bug was confirmed in 36 Illinois counties, including Woodford and Hancock counties, which were added to the list in early February.

Who goes? Who stays?
Estes says pest population predictions start with understanding pests that overwinter versus migrate. Here’s a breakdown on common Midwest corn and soybean pests.