As the distinct drone of a single-engine aircraft sounds, an airplane drops rapidly toward the earth, then pulls up to spray over the field below it.
The closest most folks have been to what is still commonly called crop dusting was the famous scene in the 1959 Alfred Hitchcock thriller "North by Northwest."
But many region residents have been seeing the low-flying planes this season and wondering why.
"Crop dusting is a growing thing to keep up with the increased demand for corn. ... It's prevalent across the Midwest," said Gary Fulk, manager for Ceres Solutions in Roselawn.
His company has arranged for certified crop dusters, otherwise known as aerial applicators, to cover the work since the beginning of July in Lake, Porter, LaPorte, Newton and Jasper counties in Indiana as well as southwest Michigan and nearby Illinois.
Hebron farmer Ron Buchanan said this was the first year he has had fungicide applied aerially.
"A lot of guys do it every year and claim there is a yield advantage," Buchanan said. "In my case, I was told it's almost a perfect storm this year for fungi. ... It was a cool, wet spring, then it was hot. This was the year to do it. I would have a substantial yield loss if I didn't."
Agronomist Kiersten Wise, associate professor and extension specialist in the Department of Botany and Plant Pathology at Purdue University, said there has been a marked growth in the use of foliar fungicides aerially applied to corn and soybeans since 2007.
"This is partly driven by the increase in crop price that allows farmers to use more inputs and encourages them to protect yield," she said. "We also have instances where conditions favor diseases ... but this varies from year to year and field to field."
Buchanan said his 150 acres of corn was hit by hail earlier this year. It caused the corn leaves to shred.
"They are more susceptible now," he said.
Christopher Hurt, an agricultural economist and professor at Purdue, said he has had several calls asking why so much aerial spraying is being done this year.
"One reason is that the crop has high yield potential and they want to protect that potential. Secondly, farmers have a very large investment in the crop, and they want to protect that investment," Hurt said.
Ever since corn fungicides were developed in 2007, there has been an increase in aerial applications to crops, said Leo Reed of the Office of Indiana State Chemist at Purdue. His office checks licensing for crop dusters.
"Essentially, the number of license applications has doubled since 2007," he said. Then, there were 109 licensed to operate. Now, it's around 220, he said.
Fulk, whose company helps farmers develop crop management plans, among other things, said of applying fungicides aerially, "It's very responsible. We're doing it for all the right reasons."