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RESULTS

(14)

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: Crown gall

HOST: Grape

Grape with multiple galls on trunk resulting from systemic infection.

DISEASE: Crown gall

HOST: Grape

Multiple small galls on trunk of systemically infected grape.

DISEASE: Crown gall

HOST: Grape

Gall on base of 'Zinfandel' grape in California, where aerial galls are less common because of dry, hot weather.

DISEASE: Elm yellows

HOST: Elm

Symptoms of elm yellows occasionally appear on one branch before others, but more often they involve the entire crown.

DISEASE: Elm yellows

HOST: Elm

Diseased twig (right) with epinasty, chlorosis, and yellowing of leaves. Sometimes both yellow and green leaves occur on same branch. Healthy branch (left).

DISEASE: Elm yellows

HOST: Elm

Branches with butterscotch discoloration (center) and necrotic flecks in phloem and vascular cambium (right). Healthy branch (left). Sudden wilt and browning is common with small trees.