Posts Tagged: gypsy moth
“Invasive insects, diseases and plant seeds can move on cut Christmas trees and other holiday greenery,” said Janice Alexander, UC Cooperative Extension forest health educator in Marin County. “These pests can escape out into backyards and neighboring forests to begin new populations, upsetting the balance of our native ecosystems. Proper purchasing and disposal of holiday greenery helps reduce that risk.”
Alexander recommends taking advantage of local tree recycling programs.
“You should not try to burn the wood indoors as fresh sap can create fire hazards,” she added, “and don't set the tree out in a backyard brush pile where pests and weed seeds could escape onto your property.”
“The most worrisome pests that might be traveling on Christmas trees or greenery this year include P. ramorum, pine shoot beetle and gypsy moth,” Alexander said.
The movement of some fresh trees is regulated. For example, Douglas fir trees are regulated because they are hosts for Phytophthora ramorum, which causes sudden oak death. The disease has killed millions of tanoak trees and several oak tree species in forests throughout California since the mid-1990s.
Pine shoot beetles, Tomicus piniperda, feed on shoots, stunting the growth of pine trees. Large populations of the insects can kill apparently healthy trees.
Gypsy moth, Lymantria dispar, attacks forests and landscape trees, including manzanita, western hemlock, Douglas fir and live oak. Gypsy moth caterpillars feed on hundreds of plant species and are capable of defoliating trees at an alarming rate. A single gypsy moth caterpillar can eat up to one square foot of leaves per day, according to the California Department of Food and Agriculture.
For more information about sudden oak death and forest health, visit Alexander's website at http://cemarin.ucanr.edu/Programs/Custom_Program816. More information about holiday greenery pests can be found at the USDA APHIS website and the Don't Move Firewood website http://www.dontmovefirewood.org/HolidayGreenery.
The California Department of Food and Agriculture has decided to spray a natural pesticide commonly used on organic farms in the Ventura County community of Ojai to knock down a local infestation of gypsy moths, according to an article in the Ventura County Star.
The gypsy moth was deliberately introduced into the United States in 1868 by French scientist Leopold Trouvelot, who wanted to breed a disease-resistant, silk-spinning hybrid caterpillar. Some moths escaped from his Massachusetts lab and the insect became a notorious pest of hardwood trees in the eastern United States, according to a Wikipedia article on the moth.
Four gypsy moths were trapped in Ojai in June 2007; 15 months later, CDFA placed a five-acre area under quarantine. Among other trees, gypsy moths' presence in Ventura County threatens California native oaks. Star reporter Stephanie Hoops contacted UC Cooperative Extension farm advisor Ben Faber for information about CDFA's planned eradication program.
Faber told the reporter that the pesticide to be used, bacillus thuringiensis kurstaki, is safe and a good way to stop the gypsy moth from defoliating oak trees.
“The thought of our hillsides without oaks is scary,” Faber was quoted. “I hope people would consider the ecological consequences if we let the gypsy moths get away.”
Gypsy moth larvae