RSF Association seeks ways to combat lerp psyllids
The Rancho Santa Fe Association hopes to devise a plan to help combat the red gum lerp psyllid and prevent it from feasting on Covenant eucalyptus trees.
“If we lose tens or hundreds or thousands of our trees the ranch will be forever changed in its look,” said Association President Bill Beckman. “We need to do what we can to save the trees.”
“We need a plan for the beautification of Rancho Santa Fe,” said longtime resident Ann Sensibaugh, who expressed concern about losing trees. “It’s ugly.”
The topic will again be on the agenda at the board’s next meeting on July 16.
David Shaw, farm adviser for the UC Cooperative Extension of San Diego County, is encouraging residents to keep watering their trees, perhaps inject their “most cherished” trees with pesticides and remove dead or hazardous trees.
Shaw said dead trees are identifiable by their shrunken or cracked bark. If the bark appears damaged as such, "(the trees) are not coming back,” he said.
Paul Flores of Rancho Tree Service said the separated bark areas are “open wounds” for other insects to get inside.
Replanting is also something Shaw strongly recommends that the Ranch look into.
“We really don’t have enough people planting trees and with a diversification of the species,” Shaw said.
Not only are the red gum eucalyptus trees susceptible to lerp psyllids, they are also highly at risk for longhorn beetles that bore into trees, as well as eucalyptus turquoise beetles, which chew the leaves, giving them a scalloped look.
A different species of eucalyptus, like the red iron, is less susceptible to the insects.
The red gum lerp psyllids cover eucalyptus leaves with white lerps, sucking out the trees’ juices. The trees lose their leaves, their bark shrinks and they eventually die.
Additionally, the lerps excrete a fluid that splatters messily on sidewalks and cars.
Around 2000, the lerp psyllid’s enemy, the parasitoid wasp, was released in San Diego County and helped decrease the lerp population.
“Early in the season, when it’s cold we get a lot of lerp psyllid activity but when it heats up we see the wasps come in and control them,” said Shaw.
Options are to inject trees with pesticide or wait for the wasps to come with warm weather. But, Shaw said some believe that the wasps have become ineffective.
“The jury is still out on whether the lerp psyllid is now immune to the wasps,” Shaw said.
Resident Larry Whitaker said he and his neighbors have had luck injecting the pesticide Imicide, which is also known as Merit. Whitaker has hired KC Horticultural to do the work since the problem first arose in 2001.
Whitaker said he thinks the association waited too long in 2001 to do something to save the dying trees.
“It was only because it was not politically correct to inject with Imicide that they lost the 80-year-old trees,” Whitaker said. "[The association] sat there for six months and watched the trees die.”
This year, Whitaker said he and 10 of his Rancho Del Rio neighbors got their trees treated early and have had no problems with the lerps.
Shaw said the cost of injections is $15 to $25.
“If you’re injecting your trees, you get on what I call the pesticide treadmill and become more dependant on that when sometimes it makes more sense to replant,” Shaw said.
Flores said he believes in a combination of more watering and injection on select trees.
Resident Bill Schlosser, who said he lost about 184 trees in the Witch Creek Fire, reminded the association to involve the Rancho Santa Fe Fire Protection District in any plan they come up with.
Rancho Santa Fe Foundation Chair Christy Wilson also reminded the board about the Forest Health Task Force. Established in 2000, they have about $8,000 and are willing to help with community education.