Prevent herbicide injury in residential neighborhoods

CARROLLTON, Mo. – Kathi Mecham, a field specialist in horticulture with University of Missouri Extension, says herbicide injury isn’t limited to agricultural areas. Garden and landscape plants can also be harmed, and reports from Carroll County last season illustrate the problem.

A community garden suffered herbicide damage twice, and a homeowner reported injury to three mature oakleaf hydrangeas after a neighbor sprayed for weeds. A mature tulip poplar in the same neighborhood was also affected. Other incidents involved oak trees, dogwoods and native flower gardens.

“Most times, the neighbor who sprayed was unaware of the damage they caused,” Mecham said. Each year Mecham receives numerous calls about vegetables harmed by drifting herbicides. “It’s very disappointing when time and money are spent on plants and they are damaged by what could have been avoided with some precautions,” she said.

Mecham and other MU Extension horticulturists are highlighting the importance of proper pesticide use during National Pesticide Safety Education Month, sponsored each February by the Weed Science Society of America, the American Phytopathological Society and the Entomological Society of America.

Identify the problem first

Before using a pesticide, carefully identify weeds, insects and diseases, and consider alternatives. “Spraying the wrong pesticide can be costly and damaging,” Mecham said.

Read the label

Always read ingredient information and instructions before use. “The product name alone may not be enough,” Mecham said. “Companies sometimes change active ingredients, so what you used in the past may not be the same this year, even if the packaging looks similar.”

Consider environmental factors

Pesticides can pose risks not only to your own yard but also to neighboring landscapes, wildlife and people. Vapors and particles can drift for miles. Avoid spraying when wind speeds exceed 10 mph, temperatures rise above 80 F or when rain is expected within eight hours. Also avoid spraying near bees and other pollinators or gutters leading to storm sewers.

Apply correctly

Move slowly when spraying; drift increases with pressure and speed. Reduce overspray by using nozzles that produce large droplets and by applying products close to the ground.

Available resources

MU Extension horticulture specialists offer guidance on integrated pest and pollinator management.