Do high-clearance sprayers knock down corn plants on end rows? Yes, obviously. Does it make a difference in final yield? Hmm. The assumption would be that if it does, it’s minimal because sprayers with up to 120-foot booms don’t make that many passes.

So, why talk about it? In the past, this topic fell in the “out of sight, out of mind” category, but with today’s drones with cameras and a resurgence of late-season scouting, sprayer tracks are showing up in fields, especially if the sprayer has wider tires.

“It’s something we’re going to pick up flying over a field,” says Steve Gauck, a regional agronomy manager for Beck’s, based near Greensburg, Ind. “I flew my drone over a soybean field recently. Even though I wasn’t looking for it, tracks from the driving pattern for the sprayer in the adjacent cornfield stood out.”

Gauck recently compared fungicide applications done by drone, airplane or helicopter, and ground rig for a presentation at a field day. “There are trade-offs, but it is true that you don’t run over any crop with an aerial application, either by drone, airplane or helicopter,” he notes.

More growers appeared to contract for at least some drone application of fungicides this year. There were many reasons why, including getting an applicator when they needed one and applying in irregular-shaped fields, and the benefit of not running over plants was a bonus.

Related:Don’t spray tar spot at dent stage

Put in perspective

Not all corn that is knocked down by a spray rig during a late application of herbicide, nitrogen or fungicide is on end rows. If the sprayer tire happens to line up over a row, 20, 30, 40 or more feet of row can be demolished before the operator realizes.

How do you know if this occurred? If you do old-fashioned scouting, even walking fields at or after pollination, those holes show up. It can happen in fields even where operators are experienced, due to things like differences in row patterns between planters and sprayers.

With GPS guidance, especially if you run RTK or a similar system, knocking down long stretches of crop shouldn’t happen frequently, says Dan Quinn, Purdue Extension corn specialist. Still, when running at speeds of 12 miles per hour or more, even a small miscue can mow down cornstalks.

MISSING ROW: If the high-clearance rig gets off track, it can take down lots of plants quickly. (Tom J. Bechman)

Quinn acknowledges that this issue has not been looked at often. For a long time, it’s been considered a cost of doing business. Like Gauck, however, Quinn realizes that with the ability to see aerial images of every field today, small bobbles stand out. Often, stalks run down by sprayer tires don’t recover or produce ears.

Quinn advises at least taking this issue into account, even if it doesn’t make a large difference on a per-acre basis. If you’re committed to a high-clearance rig for these applications, do what you can to minimize damage, including considering narrower tires. Make sure the operator is well-trained and rested too.

Across the rows:
Corn heads into home stretch

If it doesn’t look like harvest is approaching in your area yet, it will soon. And while it appears a big corn crop is on the way nationally, there will be hiccups here and there. Here is a sampling of what is happening across the Corn Belt:

In Michigan. Look for a warmer-than-normal and drier-than-normal trend in Michigan through September and into October, reports Jeff Andresen, Michigan State University ag climatologist. These trends will likely spill outside state borders into other areas of the eastern Corn Belt.

Despite some cool spells here and there, Andresen says the growing season for all but northern areas of Michigan will likely accumulate 100 to 150 more growing degree days than normal. It’s also why many crops matured ahead of schedule during the summer this year. — compiled by Tom J. Bechman, from Andresen’s talk at the weekly MSU Thursday ag breakfast virtual meeting

In Ohio. “As of Aug. 27, 2024, the projected results for Ohio show optimistic yields for Wooster, neutral projections for northwest Ohio (near average) and lower yields for western Ohio. These projections are in agreement with recently dry conditions that have affected many areas in the state, especially the southern region. 

“By Aug. 27, 75% of Ohio was abnormally dry or worse. Corn begins to scale down its water use as the crop approaches maturity. With most of Ohio’s acreage at the dough or dent stages now, we can expect a smaller effect of drought on yields relative to if drought had come in earlier. Given the faster crop progress and dryer conditions, corn harvest is expected earlier this year.” — Osler Ortez, Ohio State University Extension corn specialist, writing in the OSU C.O.R.N newsletter for Aug. 27

In Illinois. “The corn and soybean crop across Ford County is progressing well, with most fields reaching the later stages of grain fill. The drawn-out planting season is still apparent, with a range of crop maturity observed across the county.

“Of cornfields surveyed, most were in the early to mid-dent (R5) stage, but I found a few fields still in dough (R4). Most cornfields showed little disease, although a couple fields I visited in the northern part of the county were showing signs of tar spot, confirmed by the University of Illinois Plant Clinic. Soil moisture conditions in fields surveyed were good, with the crop showing little to no moisture stress despite base temps in the 90s during my survey.” — Talon Becker, University of Illinois Extension commercial agriculture specialist, Ford County, writing in the Illinois Extension Bulletin for Aug. 30

In Nebraska. Corn has already reached the dough stage across the Corn Belt, while dent stage, or even black layer, has been attained in the southern fringe of the region. Similar results are expected compared to our previous forecasts: There is a high probability of near-average yields in irrigated sites. For rain-fed corn, yields are expected to be near or above-average, except for a few sites in western Nebraska and Kansas, where there is a high probability of below-average yields.

Overall, regional average yield this season is expected to be above the historical yield trend (+6% yield deviation).

These forecasts do not take into consideration problems with stand emergence, hail and flooding damage, replanting situations, disease, or nitrate leaching. In fields negatively affected by these constraints, actual yields will be lower than estimates provided here. — from “2024 corn yield forecasts as of Aug. 27” published in the University of Nebraska Extension Cropwatch Newletter for Aug. 28