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Oregon battles Japanese beetles

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But state's gypsy moth populations are down


 Oregon's traditional insect pest of most concern seems to have been replaced this year by another unwanted bug. While populations of gypsy moth have been low the past couple of years, Japanese beetle activity has increased. As a result, there are no gypsy moth eradication projects scheduled this spring for the third year in a row. However, three separate eradication projects for Japanese beetle will be taking place this spring and summer in Oregon.


The lack of gypsy moth activity is welcome news to the Oregon Department of Agriculture, but officials say it is 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 agriculture and natural resources," says Helmuth Rogg, manager of ODA's
Insect Pest Prevention and Management Program.

Last year, for the first time since wide-scale trapping began back in the 1980s, not a single gypsy moth was detected among the 11,000 or so
traps that were placed throughout the state. That followed a detection count of only one in 2010 and just six in 2009. By contrast, more than 19,000 of the plant-eating insect pests were trapped in Lane County alone in the mid-1980s.

"For three years now, we have not had a gypsy moth eradication project in Oregon," says ODA entomologist Barry Bai. "Historically, we have been treating gypsy moths nearly every year, but the last eradication project was in 2009 in south Eugene. Since then, it has been quiet."

It is tempting to believe that gypsy moth no longer is a threat to Oregon. But the invasive insect continues to be well established in other states back east and could easily be introduced once again.

"The gypsy moth populations appear to be going in cycles of 10 to 12 years," says Bai. "The past few years, gypsy moth populations back east have been down. But we would expect those populations to build back up again which is why we need to continue setting up the traps in Oregon."

New introductions of gypsy moth to Oregon have routinely taken place in past years. New residents or travelers from areas where gypsy moth populations are high 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.

Oregon may be spared of gypsy moth projects in 2011, but its northern neighbor is not. Plans are underway for the State of Washington to treat two separate areas of Pierce County this spring after breeding populations of the moth were discovered last year.

In May, ODA expects to place another 11,000 or so gypsy moth traps throughout Oregon to see if the pest has returned. Traps will be checked and removed by early fall.

A break from treating gypsy moths this year gives ODA more time and resources to continue fighting Japanese beetle. A record high 34 Japanese beetles were found in traps last year at three separate areas of Oregon. Each will receive treatments in both the spring and summer.

"Last year, we found 16 beetles at the Portland International Airport and the surrounding area," says Bai. "We also found four beetles in an area of Troutdale and 14 beetles in Cave Junction in southern Oregon."

Japanese beetle is a major plant pest in other parts of the United States. 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.

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 the past two years.

Treatments this spring and summer will be localized.

"We want to do a one-two punch for Japanese beetle," says Bai. "Punch number one will target the larval stage while the beetles are grubs feeding off the roots of lawns and turf. Punch number two will target the adult stage after they emerge as flying insects that can chew on foliage and trees."

The first applications this spring will involve treating the soil of infested areas with a granular pesticide. In the summer, a pesticide spray will be applied to foliage in those targeted areas. In Cave Junction, the infestation is restricted to a few blocks surrounding the original home where the pest was detected. The Portland area also involves specific areas of focus that are relatively small. Despite the limited size of the areas to be treated, ODA is always concerned because of the difficulty in controlling Japanese beetle populations.

There are plenty of other insect pests of concern to keep ODA busy. Also on the radar this year, as it has been in past years, are
brown marmorated stink bug, spotted wing drosophila, light brown apple moth- all of which have been detected in Oregon already- and at least two species that thankfully have not been detected yet, Asian longhorned beetle and emerald ash borer. Detection efforts will continue to be important as ODA survey technicians get ready to check out the Oregon landscape. It will certainly be another busy year for ODA's Insect Pest Prevention and Management Program even without a gypsy moth eradication project this spring.

 

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