Playing the craps table in Las Vegas or buying a lottery ticket for a chance at more than a billion dollars doesn’t seem as risky as gambling that the high number of new, exotic insects, slugs, and other terrestrial invertebrates discovered in Oregon the past nine years are harmless.
“It’s a crap shoot and we are gambling every year,” says Jim LaBonte, an entomologist with the Oregon Department of Agriculture. “The vast majority of species we have found are believed to be relatively harmless. In some cases, a few species have actually proved to be beneficial. But a certain percentage are seriously bad and can do damage. It comes out to be one out of every seven. Every year that we roll the dice, there is a strong likelihood we will come up with a significant or major pest.”
LaBonte has been tracking all known new exotic species of terrestrial invertebrates detected and established in Oregon since 2007. There have been 88 of them, some new to North America. Out of roughly 25,000 insects, mites, slugs, and other related spineless species currently in the state, he estimates that about 1,000 are exotic. The number may also just be a tip of the iceberg.
“There has been a huge influx of species and limited resources to detect and deal with them,” says LaBonte. “This is a vast tsunami that is probably only going to get bigger.”
Exotic species are not necessarily invasive species. Exotics originated somewhere other than Oregon. Invasives cause damage of varying degrees. Of the 88 that have made Oregon their home the past eight years, 13 are known invasive species.
LaBonte has two good examples of bad actors.
“The spotted wing drosophila has had a huge impact on Oregon’s fruit industry and another recent newcomer– the azalea lace bug– is causing a lot of damage to azaleas and rhododendrons.”
Even though ODA has a contingent of experienced experts who can identify these species when they are discovered, it isn’t easy to keep tabs on so many invertebrates. Some sneak in undetected. For many species, there are no traps or lures. Sometimes the only way to find them is to literally turn over a rock. That’s why several of the exotics may be legacy species that have been present in Oregon for decades or longer with nobody recognizing them until the past few years.
Spread over the nine years, the average number of new species established in Oregon comes out to nearly 10 per year. Last year was a banner year, in a negative way, as 20 new exotic terrestrial invertebrate species were found in the state for the first time. The 20 new species are nearly twice as many as the previous two years combined. The reason for the increase is a combination of factors, not the least of which is that ODA is out there looking for insect pests in general. Surveys for specific, known pests included traps that were able to capture some previously undetected species.
The list of known major pests included in the detections since 2007 contain some names well-known to agricultural industries and others—barred fruit-tree tortrix, cabbage whitefly, ash whitefly (left), rose stem girdler, hemp russet mite, and garden slug. Some were found because of ODA’s survey work, others were samples submitted to the agency’s Insect Pest Prevention and Management Program experts.
Where do the new exotic species come from? The answer may be surprising. Despite Oregon’s strong trade ties with Asia, nearly half of the 88 species detected since 2007 originated in Europe. Asia is responsible for 19 percent, another 19 percent came from other regions of the United States— dispelling the notion that exotic or invasive species all come from other countries.
The onslaught of new species may seem overwhelming. But for the “glass half full” crowd, at least it’s not as bad as it could be.
“We aren’t like California or Florida– both of whom have huge ports that can bring a major influx of exotic species through global trade,” says LaBonte. “On the other hand, Oregon is a popular place for people to move to and they sometimes unknowingly bring in some species. Gypsy moth and Japanese beetle are exotic pests established in other parts of the US that have been brought to Oregon by people who’ve moved here.”
LaBonte has a few targeted messages for Oregonians who would rather be part of the solution instead of part of the problem.
“When you travel abroad or purchase items from other countries, be cautious. It’s easy to unwittingly bring in infested material. Suitcases are one of the primary modes of introduction to Oregon as many of these species are excellent hitchhikers. Also, be aware of damage in your vicinity. If you see something suspicious like trees dying that you wouldn’t expect or insects that seem unfamiliar, contact ODA.”
LaBonte will present the latest information on Oregon’s exotic terrestrial invertebrates at an international conference of entomologists meeting in Orlando, Florida later this year, hoping others recognize that Oregon is actively looking for new species, especially those that can cause harm. Interest in the topic at the conference is a reminder that every state and country has similar issues with exotic species crossing borders on a regular basis.
“The conference will hopefully give us an opportunity to collaborate and get better ideas on what to look out for, how to look for it, and what to do about some of these species that are Oregon-bound,” says LaBonte.
Surveillance will always be the first line of defense and ODA remains active in survey work. In 2015, more than 140 species were targeted, but LaBonte says that was a drop in the bucket as there are thousands of species out there that could cause problems. Nonetheless, LaBonte and his cohorts will not wave the white flag.
“We have detected species early on in the past, before they became permanently established, and we’ve been able to eradicate them. Just because the issue is daunting doesn’t mean you shouldn’t tackle it.”
The challenges are significant, but when there are successes in keeping invasive species at bay, the effort is worthwhile.
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