DISEASE: Crown gall
HOST: Aspen
Aspen with large, encrusted gall.
Crown gall | Aspen
DISEASE: Crown gall
HOST: Aspen (Populus sp.)
PATHOGEN: Agrobacterium tumefaciens
PATHOGEN SYNONYM: Rhizobium sp.
SOURCE: S. Thomson
DISEASE: Elm yellows
HOST: Elm
Elm yellows is characterized by witches'-brooms and stunting. Some cultivars have both yellow and reddish foliar discoloration.
Elm yellows | Elm
DISEASE: Elm yellows
HOST: Elm (Ulmus parvifolia)
PATHOGEN: 'Candidatus Phytoplasma ulmi'
PATHOGEN SYNONYM: Phytoplasma Elm yellows group
SOURCE: W. Sinclair
DISEASE: Fire blight
HOST: Pear
Blossom blight is first seen as water-soaked spots that rapidly turn brown to black as the disease becomes systemic and progresses down the shoot.
Fire blight | Pear
DISEASE: Fire blight
HOST: Pear (Pyrus communis)
PATHOGEN: Erwinia amylovora
SOURCE: S. Thomson