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RESULTS

(11)

DISEASE: Angular leaf spot

HOST: Tobacco

Leaf with light brown, angular spots. The difference between this disease and wildfire of tobacco is that wildfire is caused by a strain that produces tabtoxin. It causes conspicuous halos around lesions and large parts of a leaf may turn yellow .

DISEASE: Angular leaf spot

HOST: Tobacco

Yellowing of adjacent tissues occur as spots age (midseason). It causes conspicuous halos around lesions. Large parts of a leaf may turn yellow.

DISEASE: Angular leaf spot

HOST: Tobacco

Severely diseased leaf with extensive yellowing.

DISEASE: Bacterial blight

HOST: Hazelnut

Diseased young tree with discoloration of the cambium. Dieback of young twigs and branches is characteristic. Other typical symptoms are bud and twig necrosis and small, angular or round, water-soaked leaf spots.

DISEASE: Corky root

HOST: Lettuce

Corky root causes a reduction in size of lettuce heads and root systems; susceptible cultivar (right) and resistant cultivar (left).

DISEASE: Corky root

HOST: Lettuce

Close-up of root with malformed, corky appearance and longitudinal ridges of brown tissues.

DISEASE: Corky root

HOST: Lettuce

Initial symptoms of disease are yellow lesions on taproot and main laterals. Greenish brown bands occur around roots. Root pith may become brown and hollow.

DISEASE: Corky root

HOST: Lettuce

Differences in corky root symptoms between susceptible cultivar (right) and resistant cultivar (left).

DISEASE: Wildfire (Angular leaf spot)

HOST: Tobacco

Characteristic symptoms are necrotic, brown spots with angular margins surrounded by distinct yellow halos. The halos are caused by the production of tabtoxin.