Psyllid Movement and Location in Trees

University of Florida entomologist Kirsten Pelz-Stelinski presented an abundance of facts about Asian citrus psyllids at the recent Florida Citrus Growers’ Institute in Avon Park. Her presentation included a discussion on how far the HLB-spreading psyllids can travel and where they are predominantly found in citrus trees.

“They’re quite capable of long-distance movement, about four miles we determined,” Pelz-Stelinski says. “And that could be even greater depending on the wind conditions. The wind could propel them more. Laboratory studies have shown that they can fly continuously for about three hours. And they can also utilize some non-host plants to refuel during the long flights,” which means they don’t need citrus trees around to keep moving.

“You’re going to find the most psyllids at the very top third of the canopy of the tree,” she adds. “Psyllids are attracted to light … So they’re going to be in that top portion of the canopy. You can detect them in the bottom third and the middle third of the tree, but what that’s going to indicate is that you probably have more abundant populations than you’re actually detecting … You put traps out above the tree, below the tree, between trees, you’re not going to catch very many psyllids. So it’s not going to reflect what you have in your grove.” Bottom line: Growers should include psyllid sampling from the tops of their citrus trees to accurately determine the number of psyllids in groves.