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: Deep bark canker
HOST: Walnut
Pits in the wood and black streaks in inner bark are key diagnostic symptoms.

Deep bark canker | Walnut
DISEASE: Deep bark canker
HOST: Walnut (Juglans regia)
PATHOGEN: Brenneria rubrifaciens
PATHOGEN SYNONYM: Erwinia rubrifaciens
SOURCE: N. Schaad, M. Schroth
DISEASE: Slime flux
HOST: Casuarina
Slime flux occurs on a number of tree species and is always associated with bacteria and yeast. However, the causal agent has not been identified.

Slime flux | Casuarina
DISEASE: Slime flux
HOST: Casuarina (Casuarina equisetifolia)
PATHOGEN: Causal agent unknown
SOURCE: W. Sinclair