Microscopic Nematodes Could Prove Big Nag for Hemp Growers in Florida
July 20, 2021 For two years through a pilot project, University of Florida scientists have studied whether or not industrial hemp can serve as a viable alternative crop for Florida farmers. Signs indicate yes. However, one of the first steps to determining the economic feasibility of any crop is managing its known and potential pests. For hemp, that includes nematodes.
The worm-like nematode is ubiquitous in Florida, says Johan Desaeger, a UF/IFAS Assistant Professor of entomology and nematology.
“Root-knot and sting nematodes are considered major limiting factors to crop production in Florida,” he says.
That’s one reason one of his graduate students did her master’s thesis on the ability of certain hemp cultivars to host nematodes. As it turns out, hemp is adept at hosting the microscopic worms.
In her recently defended thesis, Jacqueline Coburn explored which hemp cultivars might be vulnerable to nematodes.
“Learning how to manage the problem is the next step,” Desaeger says. That will involve screening more hemp germplasm to find cultivars that might resist nematodes as well as looking into existing chemical and biological nematicides to reduce nematodes.”
In greenhouse trials, all hemp cultivars were good hosts for root-knot nematodes, although some cultivars, such as ‘Cherry Blossom’ showed less root damage, adds Desaeger, who supervised Coburn’s research.
“Our research shows that root-knot and reniform nematodes, especially, could pose a threat to hemp production in Florida,” Desaeger says. “More studies are needed to identify cultivars that are more resistant to these nematodes. Knowing the host preferences of nematode pests to hemp provides a better understanding of which hemp varieties are better suited for agricultural use in Florida.”
Specifically, researchers noticed negative effects – such as poor growth — on hemp when root-knot pressure was high. In most greenhouse tests, researchers add nematodes to pasteurized soil. In this test where they saw clear negative effects on growth, they used field soil from a highly infested cucumber field, Desaeger says.
Sting nematodes did not reproduce well on most hemp cultivars, except ‘Tygra’.
Scientists found a lot of root-knot nematodes on hemp in field trials in South, Central, and North Florida, especially in the second season.
Research on hemp and nematodes has been very limited globally and non-existent in Florida, so this research marks the first of its kind.
“Whether or not hemp production in Florida will become a viable industry remains to be seen but finding effective ways to deal with nematodes will be necessary for its success,” Desaeger concludes. “UF/IFAS has a long and renowned history in studying nematodes and has the expertise and commitment to helping growers control these hidden and potentially devastating crop pests.”