What’s New in IR-4 Research

Karla Arboleda Avocado, Research, Top Posts

By Karla Arboleda

Inter-regional Research Project 4 (IR-4) researchers at the University of Florida (UF) recently helped to approve an herbicide for stevia.

Janine Spies, the IR-4 southern region field coordinator at UF, focuses on collecting residue data in field trials for various specialty crops. In collaboration with researchers located in 13 states as north as Virginia, as west as Texas and south to Puerto Rico, Spies’ team follows Environmental Protection Agency protocol to submit results.

In the Southeast, researchers focus on collecting data from stevia, avocado, mango, passion fruit, dragon fruit and miracle fruit, among other crops.

“Tropical fruits are a big one; IR-4 kind of pulled back from crops that already have a lot of financial support and focused on some that have fallen by the wayside a little bit,” Spies said, adding that IR-4 focuses on pest, disease and weed issues. “We’ve really taken notice of what products work well with our beneficial organisms and pollinators.”


In order to advance stevia from its status as an emerging crop, researchers have worked to establish S-metolachlor (Dual Magnum) for growers. This herbicide could help with some common weeds in stevia, including yellow nutsedge, common purslane, annual grasses and broadleaf weeds.

“(Stevia is) kind of a newer crop, and acreage is pretty small, so you don’t have a lot of people who need products,” Spies explained. Additionally, researchers were motivated by the lack of weed management labeling in stevia.


As the avocado industry continues to battle issues with ambrosia beetles and laurel wilt disease, growers have struggled in the past without an approved fungicide. Propiconazole, a fungicide that IR-4 worked to establish for avocados, will soon expire on Dec. 31.

“We’ve been involved in doing the residue analysis to make sure that Propoconizole would be safe to use in avocado, and that the residue levels would be low enough to not violate tolerance levels,” Spies said. “We work with the chemical companies that make these products … If we don’t have (their) support, we can’t do our work.”

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