6 Moth Species You Need to Know About
The number of moths captured in fields this spring is a good indication corn growers in the Midwest need to make preliminary plans to address insect feeding this season.
Black Cutworm And True Armyworm Have Arrived
So far, Ken Ferrie says he is seeing significant numbers of black cutworm (BCW) and true armyworm (TAW) moths – two of the moth species that tend to show up early in the growing season.
In pheromone traps Ferrie has checked recently he has often found high numbers – between 25 and 30 moths in a two-night period. Agronomists say a significant flight of BCW is whenever eight or more moths are captured over a two-night period.
“The number of BCW found along with weather modeling tell me that central Illinois farmers will start to see cutting in their corn crops around May 23,” predicts Ferrie, Farm Journal Field Agronomist.
True armyworm moth numbers are also concerning Ferrie.
“Seventy, 80, 90 true armyworm are not uncommon to find in a trap. But here lately, we're well over 200 in some of these traps, so this tells us the pressure is high,” Ferrie says.
“Right now, the risk is true armyworm will defoliate the wheat crop – cutting off the plant heads – but it could get a little rough in corn here, too,” he adds. “It’s a situation we’re going to really need to pay attention to.”
Monitor These Six Moth Species
Of the 11,000-plus moth species in the U.S., most pose little to no threat to field corn. However, there are six key species corn growers can benefit from being able to identify. Their presence in fields is often a clue to the level of feeding pressure you can anticipate from their offspring – the larvae or caterpillars – in the weeks ahead.
The six moths corn growers can most benefit from being able to identify are: black cutworm, corn borer, corn earworm, fall armyworm, true armyworm and western bean cutworm.
Iowa State University Extension has put together a Guide to Moths In Iowa Field Crops that includes photographs and descriptions to help farmers identify five of these common moths, with the exclusion of western bean cutworm.
Farmers can also gain county-by-county insights from the Corn ipmPIPE system on where the moths are showing up and whether the populations are low, medium or high.
Corn ipmPIPE is a pest mapping and forecasting system developed by the National Institute for Food and Agriculture (NIFA), land-grant partners, along with Animal Plant Health Inspection Service and Risk Management Agency. You can check on the individual moth species here:
Black Cutworm
Corn Borer
Corn Earworm
Fall Armyworm
True Armyworm
Western Bean Cutworm
Do You Have A Pest Boss?
Ferrie encourages farmers to appoint someone on their team to be the operation’s official pest boss.
“This is the person who is in charge of all the organisms that might threaten your crop, which includes insects, weeds and diseases,” says Ferrie. “The pest boss should be a farm employee, but it’s a big job, so individual duties can be delegated to members of the team who are inside or outside the operation.”
If you don’t have a pest boss, he adds, now is a good time to appoint that person as the 2023 growing season ramps up.
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