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Clearing brush vital to preventing irrigation system damage

WEST LAFAYETTE, IN -- Early fall is a good time to clear brush and trees from around center pivot irrigation systems, a step that could help prevent damage to the equipment, a Purdue and Michigan State irrigation expert says.

"One of the greatest potential economic losses from center pivot irrigation comes from trees collapsing or rolling the spans," said Lyndon Kelley. "Tree limbs as small as 2 inches in diameter can cause a pivot tower to flip or tear off the pivot end boom if branches catch the span V bracing or end."

Branches can also become entangled in the pivot span, causing it to roll and topple the entire structure, he said.

Chemical herbicides are Kelley's first choice for getting rid of brush.

"Brush and tree control herbicides are more effective in early fall as the plants translocate the pesticide to the roots better than in spring," he said. "Spray additives are important especially in trees and brush with a waxy or oily leaf cover."

Herbicides work best on small trees. Trees that are over 5 inches in diameter at the trunk, or higher than sprayers can reach, require cutting or girdling. The stumps should be treated with an herbicide to prevent regrowth.

"The important thing is to control brush and trees that are growing in the pivot's travel area since it's far less expensive to manage these obstacles than to repair a crashed pivot," Kelley said.

For more information on brush and tree control, contact Kelley at 269-467-5511 or Additional reference materials are available at and