Tree Health in Oregon
A comprehensive state guide for Oregon is coming soon. Below are current tree health alerts tracked for this state.
View all Oregon alertsCurrent Threats in Oregon
Mountain Pine Beetle
INSECTA native bark beetle responsible for massive die-offs of lodgepole, ponderosa, and whitebark pines across western North America. Climate change has expanded its range northward and to higher elevations. Outbreaks have affected tens of millions of acres.
Ips Bark Beetles
INSECTA genus of bark beetles that attack stressed and weakened pines throughout North America. While they typically colonize dying trees, drought and overcrowding can trigger outbreaks that kill healthy timber.
Dutch Elm Disease
DISEASEA devastating vascular wilt disease spread by elm bark beetles that has killed millions of American elms since the 1930s. The fungus blocks water-conducting vessels, causing rapid wilting. It fundamentally changed the American urban landscape.
Sudden Oak Death
DISEASEA water mold disease that has killed millions of oaks and tanoaks along the Pacific coast since the mid-1990s. It also infects over 100 other plant species that can serve as carriers, including rhododendron and bay laurel.
Fire Blight
DISEASEA bacterial disease that primarily affects members of the rose family, including apple and pear trees. It can destroy entire orchards in a single season. Bacteria spread rapidly during warm, wet spring weather through blossoms and wounds.
Anthracnose
FUNGUSA group of fungal diseases causing leaf spots, cankers, and shoot blight on many shade trees. Sycamore, dogwood, maple, and oak are commonly affected. Cool, wet spring weather promotes infection of newly expanding leaves.
Powdery Mildew
FUNGUSA widespread group of fungal diseases that produce a distinctive white powdery coating on leaves and shoots. It affects hundreds of tree, shrub, and plant species. Unlike most fungi, it thrives in warm, dry conditions with high humidity.
Apple Scab
FUNGUSThe most economically important disease of apples worldwide. The fungus overwinters in fallen leaf litter and releases spores during spring rains. Severe infections reduce fruit quality and yield and can defoliate trees by mid-summer.
Thousand Cankers Disease
DISEASEA disease complex involving the walnut twig beetle and an associated fungus that has caused significant mortality of black walnut, particularly in western states. Thousands of small cankers coalesce to girdle branches and the trunk.
Armillaria Root Rot
FUNGUSOne of the most widespread and destructive forest diseases in the world, caused by a complex of honey mushroom species. It attacks stressed trees through root contact and can persist in dead stumps for decades, infecting nearby healthy trees.
Dothistroma Needle Blight
FUNGUSA fungal disease of pines that causes premature needle loss and can significantly reduce growth and vigor. It affects many pine species but is especially damaging to Austrian, ponderosa, and Monterey pines. It has increased in severity with climate change.
Verticillium Wilt
FUNGUSA soilborne fungal disease that affects hundreds of plant species including maples, elms, redbuds, and many other trees. The fungus invades through roots and colonizes the vascular system, blocking water transport. Symptoms often appear suddenly on individual branches. Maples are particularly susceptible. Olive-green to brown streaking in the sapwood is diagnostic.
Phytophthora Root Rot
FUNGUSA group of water-mold diseases that attack the roots and root collar of many tree species. Phytophthora thrives in wet, poorly drained soils. It destroys fine roots and can girdle the trunk at the soil line. Affected trees show a general decline that is often misdiagnosed as drought stress. Oaks, dogwoods, rhododendrons, and many other species are susceptible.
Bronze Birch Borer
INSECTA native North American wood-boring beetle that attacks birch trees, especially paper birch and European white birch in landscape settings. Larvae feed under the bark in a serpentine pattern, disrupting nutrient and water transport. Dieback starts at the top of the crown and progresses downward, the opposite pattern of many other pests.
Leaf Spot Diseases
FUNGUSA broad group of fungal diseases that cause discrete spots on the leaves of deciduous trees. Most are primarily cosmetic and do not seriously harm established trees. They are most common during wet spring and summer weather. Many different fungi cause leaf spots on different tree species.
Seven-spotted Lady Beetle
INSECTThis is a picture of a Coccinella septempunctata at Fort Armistead Park in Baltimore City, Maryland.
Eye-spotted Lady Beetle
INSECTEye-spotted Lady Beetle observed in the wild. Research-grade iNaturalist observation.
Painted Lady Beetle
INSECTPainted Lady Beetle observed in the wild. Research-grade iNaturalist observation.
Echo Azure
INSECTEcho Azure observed in the wild. Research-grade iNaturalist observation.
California Tortoiseshell
INSECTWas trying to insert its proboscis into the concrete, perhaps in the search for nectar or water? This was after it was fluttering around the building along the walls, then landing on the ground.