DISEASE: Apple proliferation
HOST: Apple
Spring form of the adult black-veined psyllid, Cacopsylla melanoneura, a vector of apple proliferation. In winter, adults are more greenish in color.

Apple proliferation | Apple
DISEASE: Apple proliferation
HOST: Apple (Malus domestica)
PATHOGEN: 'Candidatus Phytoplasma mali'
PATHOGEN SYNONYM: Phytoplasma Apple proliferation group
SOURCE: M. Wolf, W. Schweigkofler
DISEASE: Apple proliferation
HOST: Apple
Typical apple proliferation symptom of witches'-broom resulting from suppression of apical dominance and growth of dormant axillary buds. Branches are not usually bent down as shown here.

Apple proliferation | Apple
DISEASE: Apple proliferation
HOST: Apple (Malus domestica)
PATHOGEN: 'Candidatus Phytoplasma mali'
PATHOGEN SYNONYM: Phytoplasma Apple proliferation group
SOURCE: M. Wolf, W. Schweigkofler
DISEASE: Aster yellows
HOST: Watercress
Diseased watercress (left) and healthy plant (right).

Aster yellows | Watercress
DISEASE: Aster yellows
HOST: Watercress (Nasturtium officinale)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: W. Borth
DISEASE: Blister spot
HOST: Apple
Fruit with water-soaked spots.

Blister spot | Apple
DISEASE: Blister spot
HOST: Apple (Malus domestica)
PATHOGEN: Pseudomonas syringae pv. papulans
SOURCE: T. Burr
DISEASE: Blister spot
HOST: Apple
Water-soaked blister spots on leaves of blighted twig.

Blister spot | Apple
DISEASE: Blister spot
HOST: Apple (Malus domestica)
PATHOGEN: Pseudomonas syringae pv. papulans
SOURCE: T. Burr
DISEASE: Blossom blast
HOST: Apple
Many dead, shriveled flowers and young shoots. It differs from fire blight, with infections being relatively localized with the appearance of being "blasted".

Blossom blast | Apple
DISEASE: Blossom blast
HOST: Apple (Malus domestica)
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: M. Schroth
DISEASE: Bois noir disease
HOST: Grape
Bois noir disease may be expressed on one branch while other branches appear healthy. Note trapezoid-shaped leaves.

Bois noir disease | Grape
DISEASE: Bois noir disease
HOST: Grape (Vitis vinifera 'Chardonnay')
PATHOGEN: 'Candidatus Phytoplasma solani'
PATHOGEN SYNONYM: Phytoplasma Stolbur group
SOURCE: W. Schweigkofler
DISEASE: Bois noir disease
HOST: Grape
Typical symptoms of triangular-trapezoid-shaped, greenish yellow leaves.

Bois noir disease | Grape
DISEASE: Bois noir disease
HOST: Grape (Vitis vinifera 'Chardonnay')
PATHOGEN: 'Candidatus Phytoplasma solani'
PATHOGEN SYNONYM: Phytoplasma Stolbur group
SOURCE: W. Schweigkofler
DISEASE: Bois noir disease
HOST: Grape
Berries from infected vines are shrunken and low in sugar and have a high acid content, making them unfit for wine production.

Bois noir disease | Grape
DISEASE: Bois noir disease
HOST: Grape (Vitis vinifera 'Chardonnay')
PATHOGEN: 'Candidatus Phytoplasma solani'
PATHOGEN SYNONYM: Phytoplasma Stolbur group
SOURCE: W. Schweigkofler