There are good reasons glyphosate is the most popular herbicide in U.S. citrus groves, but there are also concerns about its use, says Ramdas Kanissery. Because of the concerns, the University of Florida Institute of Food and Agricultural Sciences weed scientist suggests alternatives that growers can consider. Kanissery discusses glyphosate and its alternatives in a presentation originally intended for the 2020 Florida Citrus Growers’ Institute, which was canceled due to the COVID-19 pandemic.
Kanissery cites a 2017 U.S. Department of Agriculture report that 540 tons of glyphosate were applied to Florida groves, with 50 percent of citrus acreage receiving the herbicide. The product is also the most used citrus herbicide in California and other citrus-producing states, he says.
“In many respects, it is a good weed management tool,” Kanissery declares. It is non-selective, non-volatile, has no odor, is non-staining, has a broad control spectrum, is relatively inexpensive and is a great tank-mix partner, the researcher says.
The concerns about glyphosate use in citrus include its non-target herbicide effects, its persistence in soil and the fact that some weeds don’t respond to it. Those include Spanish needle, dayflower, goatweed, pusley, ragweed parthenium and nightshade. Because of those concerns, growers need alternative modes of action, Kanissery says.
Alternatives he suggests include post-emergent, non-selective products, pre-emergence control and cover crops for row middle vegetation management. He reports that cover crops “significantly reduced the weed pressure in treated row middles when compared to non-treated controls.”
Kanissery reminds growers to rotate herbicide modes of action to reduce herbicide resistance/tolerance, and to carefully read and follow all label directions. Among the directions to follow are those describing proper personal protective equipment and worker safety.
Learn more from Kanissery about the use of multiple methods for weed control.
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