weed management

Herbicide Synergy and Safety: Keys to Successful Weed Management

Taylor Hillman weeds

Spanish needle can be difficult to control in citrus.

As most growers in the Sunshine State know, weed management can be difficult in Florida’s climates.

“When you think about Florida citrus production, weeds flourish in citrus tree lines and tree rows because there is a constant supply of moisture and nutrients,” said Ramdas Kanissery, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) weed science assistant professor. “So weeds are really happy and healthy there.”

weed management
Ramdas Kanissery

Kanissery is using herbicide synergy in his weed management research to find the most effective and safest ways to control weeds in groves. The system employs several products that use different modes of action and have both short- and long-term control. “Traditionally, growers utilize a post-emergent program where they apply herbicides when the weeds emerge … But it’s only a temporary solution to a permanent issue,” he said.

Several weed varieties prevalent in Florida characteristically produce a lot of seeds, which Kanissery said creates a seed bank in the soil. His research is testing different pre-emergent products with post-emergent products to find out which combinations provide the best broad-spectrum management with long-term control. “Some of the programs we are evaluating here, we can get up to four or five months of control,” Kanissery said.

The other major benefit of using different modes of action in a weed control program is keeping the efficacy of those products. Kanissery said tolerance in several varieties of weeds, including goatweed, pigweed and Spanish needle, continues to be seen.

Growers can increase their grove health with herbicide synergy programs — if they aren’t harming their trees when applying the herbicides. Drift and errant sprays can be very costly to growers, but Kanissery is conducting research to help protect trees. “There are many possible ways to hurt the crop when (managing weeds),” he said. “The chemicals can stay in the soil and can be taken up by the tree, and subsequent heath impacts could occur.”

“Especially in this HLB era, root health is really important so we are making sure that chemicals are not impacting root growth and health,” Kanissery added.

Listen to the March episode of the All In For Citrus podcast for Kanissery’s full interview and research update.

This article was written by Taylor Hillman, general manager of AgNet West.