While they might not have been as active as in past years, Japanese beetles still caused issues for farmers in the Midwest in 2020.
Erin Hodgson, Iowa State University Extension entomologist, said activity for the annual pest has been on par with previous years, and in line with expected ebbs and flows. Drought this year may have played a factor in some areas.
“If row crops are really drought stressed, they tended to move to more urban areas where plants tended to be more lush,” Hodgson said. “They are still around and active.”
She said any thoughts that there were fewer Japanese beetles around may have been due to other concerns farmers had throughout the year. From drought to the derecho that hit Iowa and Illinois, farmers may have focused their attention elsewhere.
One of the surprise pests of 2019 were the swarms of thistle caterpillars that emerged in a number of regions in the Midwest, particularly in western Iowa. Hodgson said those issues didn’t seem to repeat this year.
“I don’t think people noticed anything close this year,” she said. “They tend to really stand out when you are scouting, but I think it was more of a typical number this year. It was definitely way down.”
Hodgson did note that potato leaf hoppers were at some of their worst numbers throughout this season, especially on soybeans and alfalfa. The drought emphasized this issue and stressed plants showed a lot of damage, she said.
Hodgson said corn rootworm is expected to be a factor this year for Illinois farmers.
“The continuous corn fields will have increased problem of corn rootworm,” Peterson said. “With the conditions we are having, a quicker harvest might allow farmers to avoid too much damage, but it could carry over to next season.”
She suggested if rootworm seems to be an issue, try to avoid stacking corn on corn in the affected fields next year.
In terms of protections for the field, any chemical advances are specific to certain issues, which can cause a problem if producers are trying a mix of options.
“The industry is interested in producing more targeted chemistries,” Hodgson said. “It tends to target insects on the label, but leaves out other things. I would recommend to mix up the toolbox so you aren’t using the same thing over and over again.”
Hodgson’s suggestion is to be proactive with pest management and understand every summer can be different.
“A lot of products we have are rescue treatments — you are trying to rescue as much as you can,” she said. “As far as yield goes, it’s easier to be proactive with pest management than reactive.”
Hodgson said it’s hard to know what to expect year-to-year for a region, as conditions can change quickly, but she advised farmers to continue scouting and sampling to figure out what works.