Trees and other landscape plants in Minnesota are at risk from invasive species like emerald ash borer, gypsy moth, mountain pine beetle and thousand cankers disease of walnut. Although landscape pests can spread quickly with the help of humans, slowing the spread of invasive species preserves our natural and urban landscapes and buys time for increasing their resiliency and finding effective treatments.
Emerald ash borer (Agrilus planipennis) is an invasive wood-boring beetle that attacks and kills ash trees. Immature stages spread easily within infested wood. Areas of Minnesota are regulated due to the presence of emerald ash borer.
Gypsy moth (Lymantria dispar) is an invasive moth that defoliates many species of deciduous trees. Egg masses are spread easily on wood and other outdoor items. Areas of Minnesota are regulated due to the presence of gypsy moth.
Thousand cankers disease of walnut is caused by a pathogen (Geosmithia morbida) that is vectored by the walnut twig beetle (Pityophthorus juglandis). These organisms are widely present in western North America and also present in some areas of eastern North America. Minnesota has regulations in place to prevent the importation of G. morbida or P. juglandis.
Mountain pine beetle (Dendroctonus ponderosae) attacks and kills pine trees and can be moved in pine logs with bark. It is found in western North America but is not known to be present in Minnesota. There are regulations in place to prevent the importation of mountain pine beetle infested logs into Minnesota.
The Minnesota Department of Agriculture is working with the University of Minnesota and USDA on a few projects related to landscape pests including: