MILO, Iowa — It was muddy this spring when Robby Dittmer pulled into the field with the planter. Last week, he put the combine away and it promptly snowed.
It has been that kind of a year for farmers in Iowa.
Despite the many weather challenges, Dittmer says he was lucky. His farm saw enough rain without seeing major flooding.
Yields were good. Bugs and weeds did not cause major problems.
“I can’t complain,” Dittmer says.
The same was not true of all Iowans. Waterhemp reared its ugly head in parts of the state. Mudholes popped up all over. Producers near the Missouri River saw disastrous flooding. And a brightly colored pest called the thistle caterpillar ate up whole areas of fields on some farms, especially in the western part of the state.
On the Dittmer farm in central Iowa, a tornado made a path right through part of the farm. But the rest of the fields got enough moisture without drowning and the yields were good.
“I harvested 70 bushel beans,” Dittmer says. “I had never done that before.”
Dittmer also works as an agronomist. He says in his area, the wet conditions this year meant that applying additional nitrogen to fields paid off for many farmers. And the wet conditions also meant that fungicides on soybeans were a good investment for many.
The nitrogen sometimes meant a 30- to 40-bushel yield difference for corn, he says. The fungicide sometimes led to 6 to 10 bushels more for high-yielding soybean fields.
It was not an especially newsworthy year for weeds, according to Iowa State University Extension weed specialist Bob Hartzler, although wet conditions led to some weed issues.
“Waterhemp was our No. 1 weed,” he says. “It loves wet soils.”
There were some weed issues related to the timeliness of chemical applications, Hartzler says. Some farmers, for example, could not get into the field for timely post-emergence applications.
But other than the disastrous flooding in western Iowa, it was the thistle caterpillar that caught the attention of many farmers.
“It’s very colorful,” says ISU Extension entomologist Erin Hodgson. “They really stand out.”
They also stand out because they were plentiful enough this year to cause major losses for some producers. Large numbers of the caterpillars would completely defoliate a group of plants, sometimes leading to a loss of 5-8 bushels per acre in soybean fields.
Hodgson says 2019 was a good year overall for pests. Last year’s winter weather and this year’s moisture led to large populations of monarch butterflies as well as a number of other insects. Japanese beetles, soybean aphids and the soybean gall midge were also issues. Corn rootworm numbers were up as well.
With that in mind, she says farmers should be thinking about their pest control programs for 2020. They might want to look at the insect pressure this year and consider items such as diversified crop rotations, diverse pest treatments to combat resistance, and seed selection for resistance.