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: Potato
Chlorotic and stunted foliage with necrotic leaf margins. Other symptoms may be phyllody, virescence, purple or yellow pigmentation, and rolling of leaflets.

Aster yellows | Potato
DISEASE: Aster yellows
HOST: Potato (Solanum tuberosum)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: S. Thomson
DISEASE: Aster yellows
HOST: Potato
Stunted, chlorotic plants (left) with stiff, rolled leaves.

Aster yellows | Potato
DISEASE: Aster yellows
HOST: Potato (Solanum tuberosum)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: S. Thomson
DISEASE: Aster yellows
HOST: Potato
Diseased plant with malformed tubers.

Aster yellows | Potato
DISEASE: Aster yellows
HOST: Potato (Solanum tuberosum)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: S. Thomson
DISEASE: Bacterial leaf spot
HOST: Cabbage
Cabbage leaves with irregular, brownish lesions. The bacterium does not invade vascular tissues.

Bacterial leaf spot | Cabbage
DISEASE: Bacterial leaf spot
HOST: Cabbage (Brassica oleracea var. capitata)
PATHOGEN: Xanthomonas campestris pv. armoraciae
SOURCE: R. Gitaitis
DISEASE: Bacterial leaf spot
HOST: Cabbage
Water-soaked lesions on underside of leaf (left), and water-soaked, large necrotic lesions on upper side (right).

Bacterial leaf spot | Cabbage
DISEASE: Bacterial leaf spot
HOST: Cabbage (Brassica oleracea var. capitata)
PATHOGEN: Xanthomonas campestris pv. armoraciae
SOURCE: R. Campbell
DISEASE: Bacterial leaf spot
HOST: Cabbage
Leaf with various stages of lesion development, including water-soaked lesions.

Bacterial leaf spot | Cabbage
DISEASE: Bacterial leaf spot
HOST: Cabbage (Brassica oleracea var. capitata)
PATHOGEN: Xanthomonas campestris pv. armoraciae
SOURCE: R. Campbell