Mountain Ash: Fire blight Categories: Mountain Ash Mountain Ash Diseases Ornamental trees Ornamentals Last review date: 2025-07-07 09:45 Cotoneaster fire blight Photo by: R. Maleike Biology Fire blight is a bacterial infection of shoots which enters the plant through blossoms, vigorously growing shoot tips, young leaves, and wounds. Blossom clusters appear blighted. Shoots suddenly wilt, […]
Mountain Ash: Nectria canker Categories: Mountain Ash Mountain Ash Diseases Ornamental trees Ornamentals Last review date: 2025-07-07 09:46 Nectria canker fruiting bodies Photo by: R.S. Byther Biology Nectria canker is a fungal disease often found on twigs and branches that have been weakened by drought, frost damage, insect damage, or other diseases. Cankers are initially […]
Mountain Ash: Aphids Categories: Mountain Ash Mountain Ash Insects Ornamental trees Ornamentals Last review date: 2025-12-03 10:06 Aphid colony Photo by: Unknown Biology Aphids are small, soft-bodied insects that typically feed near the tip of growing shoots. Their feeding may deform leaves (curling, distortion) and stunt terminal growth. Aphids range in size up to 1/8″ […]
Mountain Ash: Ash borer Categories: Mountain Ash Mountain Ash Insects Ornamental trees Ornamentals Last review date: 2025-07-07 09:49 ash borer pupal ‘skeleton’ Photo by: A.L. Antonelli Biology The ash borer, also known as the lilac borer, is a member of the clearwing moth family. The adults of many clearwing moths mimic yellowjackets or paper wasps. […]
Mountain Ash: Leaf blister mite Categories: Mountain Ash Mountain Ash Insects Ornamental trees Ornamentals Last review date: 2025-07-07 09:51 Pear leaf blister mite damage on mountain ash Photo by: R.S. Byther Biology The leaf blister mite is a very tiny white, sausage-shaped eriophyid mite. They are seldom visible to the unaided eye. Eriophyid mite feeding […]
Mountain Ash: Mountain ash sawfly Categories: Mountain Ash Insects Ornamental trees Ornamentals Last review date: 2025-07-07 09:55 Mountain ash sawfly larvae feeding on leaf Photo by: S. Katovich, USDA Forest Service, bugwood.org Biology Mountain ash sawfly is a relatively new pest to western Washington. First reported in 2009, the larval stage of this insect feeds […]