Olivia McClure, Blanchard, Tobie M., Gould, Frances I.
A sprayer boom passes over a soybean field at the LSU AgCenter Central Research Station in Baton Rouge. Photo by Olivia McClure
As Zhijun Liu, left, a researcher in the LSU AgCenter Medicinal Plant Lab, watches, LSU weed science graduate student Matt Foster, right, pours a commercially available cleaning solution into a tank on a tractor at the LSU AgCenter Central Research Station in Baton Rouge. The solution is left in the tank overnight to remove herbicide residue. Liu is trying to develop an effective plant-based alternative. Photo by Olivia McClure
On many farms a single piece of equipment is used to spray all the chemicals needed to keep weeds, insects and diseases at bay.
This practice may be convenient, but it also can cost farmers. Many pesticides leave behind a difficult-to-remove residue, which can corrode and clog sprayers. Worse, this leftover product can harm the crops it was intended to protect.
Zhijun Liu, a researcher in the LSU AgCenter Medicinal Plants Lab, is drawing on his experience with plant-based medicinal formulas to develop a solution that effectively
cleans residue from spraying equipment.
A commercial farm sprayer is complex, with plenty of places for residue to stick — not only the tank and spraying boom, but also nozzles, connectors and porous rubber hoses.
The consequences of a poor cleaning job can be devastating. Pesticide residue can cause the dosage of a subsequent application to be too strong. Or residue from a pesticide that one crop tolerates could end up on another that is sensitive to it.
Farmers are commonly advised to rinse sprayers immediately after use with either water or a water-ammonia solution. Many are put off by this time-consuming process
and don’t do it, Liu learned.
“Even if these instructions are followed, it does not guarantee thorough removal of pesticide residues,” he said.
That’s because the active ingredients in many pesticides exhibit low water solubility, meaning it’s hard to wash those substances away with water. Cleaning products are commercially available, but Liu said none deliver good results.
Liu’s plant-based product has shown promising results in the first year of his project. He said it cleans hoses tainted with herbicide residue better than water alone, ammonia-water solution and WipeOut, a product made by Helena Chemical.
He is now optimizing the formulation, studying how it cleans residue of 2,4-D — one of the most widely used herbicides — and trying to identify the best ways to clean spray booms. He hopes to complete lab work and begin assessing the product’s effectiveness on the farm this year.
“It is a work in progress,” Liu said. “It is a challenging issue, but our initial research work raises the hope that a new solution could be on the horizon for an old problem.”
The LSU AgCenter and the LSU College of Agriculture