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RESULTS

(19)

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: Aster yellows

HOST: Wheat

Healthy head (left) and diseased head (right). Diseased seedlings may die within 2 to 3 weeks. Infected heads of surviving plants are small and sterile, with distorted awns.

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: Bacterial canker

HOST: Hazelnut

Primary symptoms are failure of buds to break and withering and death of new foliage in spring. Dead leaves remain attached to limbs after normal leaf fall.

DISEASE: Bacterial fasciation (Leafy gall)

HOST: Tobacco

Bacterial fasciation of tobacco.

DISEASE: Bacterial leaf blight

HOST: Wheat

Diseased leaves with whitish blotches. Initial water-soaked spots become necrotic and progress from gray-green to tannish white.

DISEASE: Bacterial leaf blight

HOST: Wheat

Diseased leaves with whitish blotches. The disease begins as water-soaked spots and then become necrotic and progresses from gray-green to tannish white.