A recent find in Oregon has weed scientists, botanists, land managers, and plant conservationists throughout the Pacific Northwest and California really excited over a tiny insect. The broom gall mite (Aceria genistae) is an insect native to Europe that has recently taken resident on the invasive plant Scotch broom in Oregon. Scotch broom was introduced into North America in the mid-1800s from Europe as an ornamental and for erosion control. Since its introduction it has formed dense stands covering millions of acres. The gall mite attacks Scotch broom by forming galls on the plants buds which greatly reduces the ability for it to grow and reproduce. The gall mite has even killed large stands of broom. For the past few years the Oregon Department of Agriculture has been monitoring the insect and its travels. Since its first sighting in 2000 near Portland the insect has travelled extensively throughout the state. In 2010, it had made its way south to Sutherlin and this spring the insect was found in Ashland just north of the California border. Researchers are continuing to conduct host specificity tests to ensure that the insect only attacks Scotch broom. Similar research in New Zealand has shown that the broom gall mite is extremely unlikely to damage anything other than Scotch broom.
Jun 1, 2012