Fact Sheets

Pear: Crown gall

Pear: Crown gall categories: Pear Pear Diseases Tree Fruits revision date: 2022-12-05 12:00 Large gall on crownPhoto by: R.S. Byther Biology Crown gall is caused by a soilborne bacterium. The bacteria infect through wounds on the crown and roots. Young galls are fleshy, white, enlarged masses on the roots or stems. Older galls are hardened […]

Pear: European canker (Nectria canker)

Pear: European canker (Nectria canker) categories: Pear Pear Diseases Tree Fruits revision date: 2022-12-05 12:00 Mature European canker on branchPhoto by: R.S. Byther Biology Nectria or European canker is a fungal disease affecting the twigs and branches of pear and apple. Young cankers occur at leaf nodes on twigs and are sunken, dark, and water-soaked […]

Pear: Fire blight

Pear: Fire blight categories: Pear Pear Diseases Tree Fruits revision date: 2022-12-05 12:00 Fire blight infected leavesPhoto by: G.G. Grove Biology Fire blight is a bacterial infection which typically attacks via wounds or blossoms. Initially, twigs and flowers appear water-soaked. Infected tissues quickly turn brown to black and die back, often bending over in a […]

Pear: Pacific Coast pear rust

Pear: Pacific Coast pear rust categories: Pear Pear Diseases Tree Fruits revision date: 2022-12-05 12:00 Pear rust infection on leaf petiolePhoto by: R.S. Byther Biology Pacific Coast pear rust is a fungal disease affecting pears, hawthorn, apple, crabapple, serviceberry, quince, and mountain ash. The alternate host is the incense cedar (Calocedrus decurrens), which develops witches’ […]

Pear: Pear trellis rust

Pear: Pear trellis rust categories: Pear Pear Diseases Tree Fruits revision date: 2022-12-05 12:00 Upper and lower leaf surface on Pyrus sp.Photo by: F. Geller-Grimm, commons.wikimedia.org Biology Pear trellis rust is a fungal disease that attacks pear trees and junipers. It is commonly reported on pear leaves in western Washington. Like many rust diseases, pear […]

Pear: Powdery mildew

Pear: Powdery mildew categories: Pear Pear Diseases Tree Fruits revision date: 2022-12-05 12:00 Powdery mildew on apple leavesPhoto by: R.S. Byther Biology Powdery mildew is a fungal disease found on twigs, leaves, blossoms, and fruit. New growth is particularly susceptible. The entire terminal may become covered with powdery mildew. Leaves develop a characteristic gray-white powdery […]

Pear: Pseudomonas blossom blast and dieback

Pear: Pseudomonas blossom blast and dieback categories: Pear Pear Diseases Tree Fruits revision date: 2022-12-05 12:00 Pseudomonas cankers on pear twigsPhoto by: R.S. Byther Biology Blossom blast and dieback is caused by a bacterial infection. The infection causes buds to turn a papery brown and die. Leaves may be spotted. Flower petals and stems may […]

Pear: Scab

Pear: Scab categories: Pear Pear Diseases Tree Fruits revision date: 2022-12-05 12:00 Scab symptoms on pear fruitPhoto by: R.S. Byther Biology Scab on pear is a fungal disease very similar to apple scab. The disease infects during wet weather in the spring and summer. Lesions appear on leaves, petioles, twigs, and fruit. The spots enlarge […]

Pear: Stony pit

Pear: Stony pit categories: Pear Pear Diseases Tree Fruits revision date: 2022-12-05 12:00 Pear stony pit virus symptoms on fruitPhoto by: R.S. Byther Biology Stony pit is a virus disease of pears apparently spread by vegetative propagation (budding, grafting, rooting cuttings). Insects are not known to carry the virus. The disease primarily affects the fruit. […]

Pear: Virus diseases

Pear: Virus diseases categories: Pear Pear Diseases Tree Fruits revision date: 2022-12-05 12:00 Apple mosaic virus foliar symptomsPhoto by: R.S. Byther Biology Virus diseases of pears in home orchards seldom cause significant problems. Symptoms of common viruses are seen on bark, leaves, and fruit. Some virus diseases may cause bark to appear roughened or blistered. […]

Pear: Aphids

Pear: Aphids categories: Pear Pear Insects Tree Fruits revision date: 2024-04-08 11:46 Green peach aphid closeupPhoto by: Unknown Biology Three aphids are commonly found infesting pear. All three species produce honeydew, a sweet, sticky material which attracts ants and that may become covered with a growth of dark sooty mold. Honeydew also causes russeting of […]

Pear: Apple-and-thorn skeletonizer

Pear: Apple-and-thorn skeletonizer categories: Pear Pear Insects Tree Fruits revision date: 2022-12-05 12:00 Apple-and-thorn skeletonizer caterpillar feeding on leafPhoto by: A.L. Antonelli Biology The adult of the apple-and-thorn skeletonizer is a small dark-brown or reddish-brown moth. It overwinters as a pupa or an adult, with the females laying eggs in the spring. The caterpillars are […]

Pear: Brown marmorated stink bug

Pear: Brown marmorated stink bug categories: Pear Pear Insects Tree Fruits revision date: 2023-04-04 12:00 Brown marmorated stink bug damage to pear fruitPhoto by: Gerald Brust, Univ of Maryland Biology The brown marmorated stink bug (BMSB) is an introduced pest species from Asia that is spreading quickly across the United States. Nymphs and adults feed […]

Pear: Codling moth

Pear: Codling moth categories: Pear Pear Insects Tree Fruits revision date: 2023-04-04 12:00 Codling moth feeding inside apple corePhoto by: J.F. Brunner Biology The brownish-gray wings of adult codling moths are marked with dark bands and a dark brown spot near the tip. Wingspan is up to 3/4″ across. Adult females lay eggs on leaves […]

Pear: Cutworms and armyworms

Pear: Cutworms and armyworms categories: Pear Pear Insects Tree Fruits revision date: 2023-04-04 12:00 Climbing cutworm, dark brown and hairlessPhoto by: K. Grey Biology Cutworms and armyworms are the larvae of noctuid moths. These common moths are typically medium-sized with fairly dull coloration. The gray to tan caterpillars are hairless, nocturnal, and generally spotted, striped, […]

Pear: Pear psylla

Pear: Pear psylla categories: Pear Pear Insects Tree Fruits revision date: 2023-04-04 12:00 Pear psylla adultPhoto by: E.C. Burts Biology The brownish-gray adult pear psylla is about 1⁄10″ long, with clear wings held rooflike over the body. The wings may have a smoky gray spot halfway along the inner margin. The red-eyed nymphs range in […]

Pear: Pear slug (pear sawfly)

Pear: Pear slug (pear sawfly) categories: Pear Pear Insects Tree Fruits revision date: 2022-12-05 12:00 Pear slug and damaged leaf from feedingPhoto by: R.D. Akre Biology The pear sawfly is also known as the pear slug (or ‘cherry slug,’ when on cherry) because of its resemblance to a small, dark slug. These insects are the […]

Pear: Pearleaf blister mite

Pear: Pearleaf blister mite categories: Pear Pear Insects Tree Fruits revision date: 2024-04-08 11:46 Pearleaf blister mite damagePhoto by: C.R. Foss Biology Pearleaf blister mites are tiny, white to yellowish eriophyid mites that feed on leaves and fruit. Damage on leaves is caused by mites feeding inside the leaf tissues, resulting in the formation of […]

Pear: San Jose scale

Pear: San Jose scale categories: Pear Pear Insects Tree Fruits revision date: 2022-12-05 12:00 San Jose scale closeupPhoto by: K. Grey Biology San Jose scale is an armored (hard) scale found on many deciduous trees and shrubs including apple, cherry, elm, maple, poplar, and willow. The scale insects are about 1⁄16″ in diameter. The female […]

Pear: Spider mites

Pear: Spider mites categories: Pear Pear Insects Tree Fruits revision date: 2022-12-05 12:00 Spider mites under microscopePhoto by: L.K. Tanigoshi Biology Several species of spider mites may be found on pear leaves, including the twospotted and McDaniel spider mites and the European red mite. They may be various colors including yellow, greenish, brown, or red. […]