Iowa State University crops specialist, Joel Dejong, says last week’s freezing temperatures have caused some widespread damage to western Iowa corn fields. “A lot of northwest Iowa and actually even into southwest Iowa — although they didn’t even freeze — they had some damage in some fields also from radiation frost where it got cold so fast,” DeJong says. “We had temperatures in the mid 20’s, so obviously that’s going to cause come crop damage.”
DeJong says in many instances corn had already emerged when the cooler temperatures had hit, and he believes most of the crop will recover. “As I go dig fields, it looks like most plants have grown quite a bit since we had that frost and these nicer sunnier days help,” DeJong says. He says some plants look like they lost a leaf, but he says they will continue to regrow.
DeJong says soybeans are a whole different story compared to corn when it comes to frost damage. “Soybeans once they emerge, their growing point is above ground. So, southwest Iowa reported several fields where they did freeze off emerged beans. I am not sure if I know of any emerged beans (in northwest Iowa) — maybe there was field or two out there. If there was, they are probably hurt pretty seriously,” DeJoung explains.
Statewide, 40 percent of the soybeans have been planted and DeJong believes northwest Iowa farmers have perhaps planted as much as 60 percent of the intended soybean acreage. DeJong says farmers will want to start scouting for black cut worms based on their tracking of the adult larvae. “We trap adults as they start moving up, they don’t live through an Iowa winter, so traps went out in mid-March and the first part of April,” DeJong says. He says the adults started showing up mid-April and he says they predict the worms will be big enough to start cutting off the plants by around May 27th.
The agronomist says the day length and temperatures will determine how fast the cutworms will move into this area. He says as the corn growth slows down, so do the insects and other pests.
By Dennis Morrice, KLEM, Le Mars