Great news. Gypsy moth count low

Only six gypsy moths detected statewide this year
By Oregon Department of Agriculture,

For the fifth time this decade, the number of gypsy moths annually trapped in Oregon is in single digits. Despite placing approximately 12,000 traps statewide, the Oregon Department of Agriculture recorded only six detections of gypsy moth, following last year’s total of 12 detections. “It has been a very quiet summer for gypsy moths, which is very positive,” says Helmuth Rogg, supervisor of ODA’s Insect Pest Prevention and Management Program. “At this point, we are not making any plans for an eradication program next spring. That doesn’t happen very often. We’re very pleased with the results. ”

In 2002 and 2006, ODA was able to take a break from spraying for gypsy moth. Previously, it was back in 1990 the last time ODA had not conducted a gypsy moth eradication project.

By finding gypsy moths as soon as possible and quickly eliminating breeding populations, ODA has successfully prevented economic and environmental losses to Oregon, either by restrictive quarantines on commodities or by the loss of foliage and even trees due to expanding gypsy moth populations. Results in recent years are a far cry from 25 years ago, when some 19,000 gypsy moths were trapped in Lane County alone.

Despite very few detections this summer, gypsy moth remains a constant threat to Oregon. ODA will continue its vigilant trapping program in 2010.

“All the detections of gypsy moth this year were at new sites,” says Rogg. “That tells me that the threat of gypsy moth coming west- usually on outdoor household articles or vehicles from infested areas back east- is still there.”

ODA survey technicians began placing gypsy moth traps throughout the state in May and removed them in late summer and early fall. It is that stretch of time when the gypsy moth is in the adult stage. Traps lure male gypsy moths with a female sex pheromone and the attracted insects get caught by the sticky substance found inside the tent-like cardboard traps.

This year’s six detections took place in Portland in Multnomah County (three moths), Aurora in Clackamas County (two moths), and Clackamas in Clackamas County (one moth).

Of the three gypsy moths trapped in Portland, two were detected in an RV park at Jantzen Beach not far from a commercial shopping center. Recreational vehicles are a known pathway by which gypsy moths can hitchhike to Oregon from infested states, usually as an egg mass attached to the recreational vehicle. Due to this risk, RV parks, campgrounds, and rest areas statewide are trapped each year. The third gypsy moth in Portland was found in an industrial area near the Columbia River.

The two detections in Aurora occurred separately about five miles apart. The single detection in Clackamas took place not far from Interstate 205.

While additional traps were placed in areas of detection, there has not been enough evidence to suggest a breeding population of gypsy moth exists at any of the sites. Additional searches for egg masses and other evidence of established gypsy moth populations routinely take place. But it appears there is no need at this time to make plans for an eradication project next spring. The six detection sites will be watched closely next year when new traps are placed.

Perhaps the best news of all is that there were no detections of gypsy moth in southeast Eugene- the site of this year’s lone eradication project- after seven moths were trapped in 2008. Also, no detections were made for the second straight year in Shady Cove, the site of a 2008 eradication project. Two consecutive years of no detections in that area means the previous gypsy moth population has been officially eradicated.

“We did not find anything in Eugene, so that means the gypsy moth has been successfully eradicated for this year,” says Rogg. “We will have another high density of traps in the area next year just to confirm that the small pocket of gypsy moths is gone.”

There is no way to predict what might happen in the future. As the general infestation of gypsy moth nationwide has moved from the east coast to the Midwest states, the threat of further spread towards the west coast increases. However, like many insect pests, the gypsy moth population back east is cyclical.

“We can see that the general population of gypsy moths is down in the infested areas of the eastern United States,” says Rogg. “Another factor may be that fewer people are traveling to Oregon from back east because of the economy. Fewer people are coming our way with the potential of carrying gypsy moth egg masses attached to their vehicles.”

So far, Oregon has been able to avoid the unsavory prospect of having to learn to live with the gypsy moth. That’s why the just-completed detection program will continue to be an important tool in fighting off an unwanted invader.

“The fact that we had a small number of detections this year shows that we have a very good program that finds gypsy moth populations while they are small and treatable,” says Rogg. “We have a good track record of eradicating small pockets of gypsy moth in Oregon as soon as we detect them. Without a good trapping program, that would not be possible.”

The Oregon Department of Agriculture’s comprehensive program of early detection and rapid response to the gypsy moth threat appears to be working well in its mission to protect the state’s natural environment and economy from the impact of an invasive species.

For more information, contact Bruce Pokarney at (503) 986-4559.

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