Dust may reduce herbicide impact

Dry soil can lead to dust when applying post emergent herbicides and can cause problems for growers.

Aaron Hager, extension weed scientist with the University of Illinois, says the large equipment used by commercial applicators kicks up a lot of dust in dry soil, which combines with the herbicide.

"Sometimes we get concerned with the amount of dust that is generated,” Hager tells Brownfield, “Because what can happen with some post-emergence herbicides that come in contact with the dust may actually reduce the weed control efficacy from that application itself.”

Hager says North Dakota State University researchers several years ago found that foliar-applied herbicides, including glyphosate, were reduced when dust was deposited on leaves before or within 15 minutes after application. He said the effect was a bit worse with dust from silty clay soil than from loamy sandy soils.

Hager says there’s not much growers can do, “For remedies, unfortunately, you know a good nice soaking rain would be one of the few remedies that actually would provide some relief.” Illinois and some other states in the Corn Belt are very dry with summer-like temperatures and there’s little rain in the forecast.

Hager says it’s a good idea to go out and scout those fields that were treated with post-emergence herbicides during very dusty conditions to see what level of weed control was achieved.