Aliens & Pests

      

Roving bug-detection patrols will be scouting southwestern Ontario this summer looking for evidence of "EAB". The inspection areas are mostly outside Essex County and Chatham-Kent, where thousands of trees have been cut to stop the spread of the Asian insect, which is lethal to ash trees. Inspectors will be visiting sawmills, private campgrounds and provincial parks looking for ash firewood that might have been brought in from infested trees. Last year, 22 fines of C$400 were imposed on people who illegally moved firewood out of the quarantined areas. Movement of wood by people is a much greater threat than natural movement of the beetle, since firewood can be hauled over long distance in a short time. Adult beetles have begun emerging in Ontario, and will be colonizing new trees However, the extent of new damage will not be known until fall or spring, after larvae have fed on the tree stems and girdled the trees. In Ohio, tree climbers have inspected trees in Maumee Bay State Park and found beetle larvae in seven trees. The trees have been removed. Ash trees within 200 yards of the infested trees were girdled to create 'trap trees.' Stressed trees are more attractive to ash borers than unstressed trees. Girdled trees are more attractive to adult beetles than ungirdled trees and trap trees may attract all the emerging adults, preventing them from flying further afield and spreading the infestation. Trap trees will be removed next spring before adult beetles emerge. The effectiveness of this strategy is not known. It is probably less effective than removing all ash trees in the area, but removal budgets are tight.

Adult emerald ash borer, Agrilus planipennis. Photo by James Zablotny, US Department of Agriculture

The latest Tangled Bank is up at Geomblog. Tangled Bank is a blog carnival for science writers. The current offering has lots of great articles and is worth a visit.