Pollination is among the most critical growth times for corn—and it often comes at the hottest, driest, most challenging part of the year. Drought, heat and insects all play a vital role in how well your corn pollinates—examine your environment to see how your crops fare.
In Herman, Neb., corn and soybean farmer Tim Gregerson is seeing the consequences of replant, hot weather and insect infestation on his pollinating corn. “Our irrigated corn is doing pretty good, but the pollination window will be long due to 25% replant,” he says. “Pollen shed is spread out field to field and within the field.”
Right now he’s about 75% through pollination on his irrigated ground and 65% on his dryland acres. When he pulls back the husk he’s still seeing most of the silks fall to the ground, a sign of successful pollination, but says there are a few missed kernels here and there and time will tell how much tip back appears. He expects to see the greatest variability on his dryland acres.
Indiana farmers find themselves in two boats—great pollination or in a bit of trouble. Just one county north of corn and soybean farmer Kurt Line, fields are really struggling with pollination. However, he’s in good shape with 80% of his fields pollinated—some fields past blister.
In southern Minnesota, Brad Nelson is looking at near perfect corn pollination. “We’re winding up now, the later planted silks are white and just starting to turn brown,” Nelson says. “It’s going to be excellent pollination.”
Right now he estimates he’s about 85% pollinated—a little later than normal. “That’s how I feel about it, we didn’t really get going [planting] until the fifth of May,” he says. “We’re seven to 10 days behind.”
With variability north to south and east to west, make sure you’re scouting to protect yield potential. As pollination comes to a close, keep an eye out for disease and insect pests that could steal precious bushels.
“Rust has been reported in the county southwest of us,” Gregerson says. “This year it came north of the Platte River, which is uncommon.”
He’s seeing mostly common rust, but is worried about the Southern Rust making its way north. “It’s the most wicked rust of all, we’re watching for fungicide,” he adds.
In addition to rust, farmers should keep an eye out for Northern Corn Leaf Blight and Gray Leaf Spot, as those diseases destroy leaf tissue and photosynthesis ability. Talk with your agronomist or chemical rep to see if you’ve caught these diseases in time for fungicide treatment to provide returns.
Northern Corn Leaf Blight lesions
Gray Leaf Spot lesions
While diseases and weather might not be putting much pressure on Nelson and Line in Minnesota and Indiana, insects are making their way into fields to take a bite out of yield. “We’re putting insecticide in with fungicide [for aphids],” Nelson says.
Aphids, Japanese beetles, and even corn borers are rearing their ugly heads across parts of the Corn Belt. In Nebraska, the Japanese beetle was especially tricky this year. “It takes good scouting, Japanese beetles hit the outside [of fields] worse than the inside,” Gregerson says.
Make sure you take five to 10 samples throughout the field before making a decision on insecticide treatment with insects like Japanese beetle or corn borer. In a tight year it’s important to make sure you’re at threshold before applying insecticide.
Here are thresholds for common insect pests around pollination according to the Farm Journal Field Guide:
- Corn Leaf Aphid—treat if 50% of plants have more than 100 aphids per plant and are under stress
- Japanese Beetle—consider treatment when silks are cut to less than ½” and less than 50% of the field is pollinated with beetles present and feeding
- Corn Borer—with the first generation determine if economic loss might occur before treating, second and third generations treat when eggs are hatching or about to hatch
- Corn Earworm— treat if 5% to 10% of the ears are infested with eggs or larvae