Gypsy moth vanish. Breaks Oregon record. — New beetle threat looms

Traps yield zero gypsy moths but 34 Japanese beetles
By Oregon Department of Agriculture

For Oregon, it’s all quiet on the gypsy moth front. For the first time since wide-scale trapping began back in the 1980s, not a single gypsy moth was detected this summer. Last year, only one gypsy moth was caught in Oregon and only six in 2009. In contrast to 25 years ago when more than 19,000 of the plant-eating insect pests were trapped in Lane County alone, it’s easy to wonder if the gypsy moth remains a threat to the state’s agriculture and forest habitat.

It’s way too early to end the vigilance.

“Gypsy moth is still an important invasive species we have to control and, in the western states, eradicate when we find it because of the impact this species has on our natural resources,” says Helmuth Rogg, manager of the Oregon Department of Agriculture’s Insect Pest Prevention and Management Program. “It’s great news that we didn’t find any this year, but gypsy moth is still worth fighting against and keeping out of Oregon.”

Nearly 13,000 brightly colored gypsy moth traps have now been removed and inspected after sitting out all summer throughout Oregon. Nobody would have predicted zero catches this year, but there are at least a couple of plausible explanations for not finding any gypsy moths.

“The gypsy moth population is in a downswing in some of the eastern states where it is established,” says Rogg. “But more importantly, the economy may have slowed down its introductions into our state. Not as many people are moving to Oregon from infested areas back east. It’s likely not as many people are traveling west as much as they used to. All of this may have contributed to keeping gypsy moth out of Oregon this year.”

New introductions have routinely taken place in past years. New residents or travelers from areas where gypsy moth populations are heavy unwittingly bring the insect pest with them on such things as outdoor household furniture or other items that may harbor gypsy moth eggs. It only takes one female gypsy moth to lay eggs in Oregon and start up a new population of the invasive species. That’s why the trapping program is so important, even in years when the detections are few. Finding gypsy moths as soon as possible and quickly eliminating breeding populations allows ODA to successfully prevent economic and environmental losses to Oregon, either through restrictive quarantines on commodities or by the loss of foliage and even trees due to expanding gypsy moth populations.

“We want to continue keeping gypsy moth from gaining a toehold in Oregon, and prevention is still the best recipe for doing so,” says Rogg. “Our detection program helps keep any gypsy moth populations that might be out there from getting big enough to cause major problems to our agricultural industry and our natural resources, including our native insects.”

ODA survey technicians begin placing gypsy moth traps throughout the state in May and remove them in the fall. During the summer, gypsy moths are in the adult stage. Traps lure male gypsy moths by using a female sex pheromone and the attracted insects get caught by the sticky substance found inside the cardboard trap.

Budget considerations reduced the number of traps this year and affected their placement. A high concentration of traps were placed in areas known to be at greater risk of gypsy moth introductions- mostly on the west side of the Cascades and in areas more easily accessible to ODA survey technicians. The strategy may have contributed to the absence of detections, but Rogg feels it is very unlikely there are some gypsy moths out there that have figuratively flown below the radar.

“Our past efforts and strong program also play a role in fewer detections in that we have kept gypsy moth populations from getting established,” says Rogg.

For the third year in a row, there will be no need for a gypsy moth treatment program in Oregon next spring. That’s the longest stretch of no eradication projects since the huge Lane County infestation of the mid-1980s, when more than 225,000 acres were treated for gypsy moth.

While the news is good regarding gypsy moth, it’s not so good regarding Japanese beetle.

“We have caught a record high 34 Japanese beetles in Oregon this year,” says Rogg. “About a dozen of them have been trapped near and around the Portland International Airport while the others have been trapped in Cave Junction in southern Oregon.”

Japanese beetle is a major plant pest in other parts of the US. As a grub, it can be very destructive to turf. As an adult, the beetle feasts on a wide variety of plants including trees, shrubs, flowers, fruits, and vegetables. For years, ODA has worked to detect and eradicate populations of the pest when they are discovered. Japanese beetle often hitches a ride on cargo planes originating in infested areas back east. That’s why detections frequently take place near the Portland Airport. Due to budget cuts, federal officials this year reduced monitoring of airports in infested locations, which may have led to the jump in Portland-area detections of Japanese beetle.

The Cave Junction infestation is traced to a new resident who moved from Iowa with potted plants that harbored Japanese beetle. It appears the insects were able to lay eggs in the soil surrounding the home which led to detections late last year and this year.

“We plan to treat that area again next year,” says Rogg. “The infestation is restricted to a few blocks surrounding the original home. We did some treatments this year, but it wasn’t enough. Japanese beetle is very difficult to control and it often takes several years to get rid of the pest population because part of the beetle’s life cycle takes place deep in the soil.”

So, Oregon’s insect pest situation is a mixed bag for 2011. But with additional budget concerns looming for next year, ODA may need to make some tough decisions about its detection programs. Not having a gypsy moth eradication project next spring may at least offer some financial relief.

For more information, contact Helmuth Rogg at (503) 986-4662.

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