Photo by Mark Gibson
THE TINY CALIFORNIA Fivespined Ips beetle, pictured above near the end of Chet Behling’s fingertip on a ravaged tree, is causing damage to timber around the gorge. Below, Behling, Oregon Department of Forestry stewardship forester for the Central Oregon District Office in The Dalles, stands next to an infested tree with brown needles.
The Dalles Rural landowners in The Dalles and Hood River need to be on the watch for a beetle that not only infests pine trees but carries a fungus that will also plunder nutrients.
The problem created by the California Fivespined Ips, while growing in the gorge, is something that can be partially controlled with careful stewardship, according to Oregon Department of Forestry officials.
“We are not sure if this beetle is new to the area, if we didn’t understand its broader geographical range in the past or if conditions have changed to attract it,” said David Jacobs, supervisor for the agency’s Central Oregon District Office in The Dalles.
“What we do know is that if these beetles are in the trees, the trees are pretty much gone.”
Chet Behling, ODF stewardship forester in The Dalles, said the Ips is native to northern California and Southwest Oregon but moved up the Interstate 5 corridor to the northern sector of the Willamette Valley and was first introduced in the Columbia Gorge in 2010. The insect has since been found as far east as Lyle on the Washington side of the Columbia and on the outskirts of Mosier, Hood River and The Dalles in Oregon. “Whatever the reason that the Ips is here, it’s moving in and it’s more aggressive about taking out the whole tree, compared to its traditional signature of killing only smaller trees and the tops of mature trees,” said Behling.
The trees attacked by Ips
include the Ponderosa pine, Western White pine and Lodgepole pine.
“Sometimes a beetle will cross over but as far as these particular bugs go, they are pretty much species specific,” said Jacobs.
Behling said other beetle species have travelled into the area but died off within a couple of years due to the nature of population dynamics and changes in environmental conditions. That does not appear to be the case with the California Fivespined Ips, which seems be settling in for a longer stay.
“When the population grows, they begin attacking healthy trees and inviting their buddies (Western Pine beetle and Red Turpentine beetle) to join in,” he said.
ODF officials say it is important for property owners living on more rural tracts of land, where beetles appear to congregate, to dispose of affected trees. They also need to get rid of slash piles and thin overstocked stands of trees. Early agency research has shown that the insect appears to be attracted in the spring and summer months to piles of woody debris, fresh pruning wounds and stressed-out trees.
The pines most at risk, said Behling, are those distressed from a lack of water or with a structural defect, such as bark that is damaged from a past wildfire.
“Healthy and more vibrant forests can withstand bugs and disease but overstocked or compromised trees are going to be vulnerable,” he said.
The adult Ips is difficult to see with the naked eye at 3 to 5 millimeters in length with bullet shaped bodies. The insect is named for the five distinctive spines on the rear of the wing cover that can only be viewed through a magnifying glass or microscope, according to Behling.
The adult male is the first to bore into the bark and create a chamber that he advertises by a combination of pheromones and chemicals emitted by the tree. Three females then take up residence in the tree and, once mating has occurred, chew a tunnel that provides them with space to lay eggs.
The young larvae feed on the soft cambium tissue underneath the bark and can develop as quickly as two weeks, but may take as long as five if conditions are not optimal.
One to two populations of beetles are typically produced each growing season so Behling said the numbers that infest the trees can grow quickly.
Creating an added problem for the embattled pine is the attack mounted by the Blue Stain Fungus that is carried by the beetles.
The fungus prevents the tree from producing resin to “pitch” out the insects and its spores block the passage of nutrients. The pine can die within one year of infestation and the presence of the fungus becomes clear by the blue-gray discoloration of wood once the tree is cut down.
Infested trees will start to show symptoms of distress with needles that turn yellow and then orange. Once the entire tree begins turning color, Jacobs said it is too late for it to recover. Other symptoms include a proliferation of exit holes, an accumulation of reddish bark dust from beetle activity and leaking sap near the dead needles.
The Ip migration is now being studied not only by ODF but Oregon State University Extension Service, Washington State University Extension Service, Washington State Department of Natural Resources and U.S. Forest Service.
“The biggest frustration is that there is no cure for eliminating the beetle,” said Jacobs. “Landowners may be able to prevent the spread to some degree, but it’s important to understand they are part of nature and historical population outbreaks normally only last a few years with this particular beetle.”
He said the Ips is creating far less destruction than the Mountain Pine beetle in Colorado that has destroyed entire watersheds and set these areas up for catastrophic wildfires.
Behling said the timing of pruning or taking down a tree to stop a beetle infestation is important for effectiveness. There is usually a window between September and April 15 where open burning is allowed so infected wood can be disposed of immediately.
He can be called to check out potentially affected trees or provide advice about stopping the spread of beetles at 541-298-4993 or via email at firstname.lastname@example.org. Jacobs is reachable at the same phone number or by emailing email@example.com.