irulence to various hosts, the transporting of infected 
rnamental plants from one area to another may 
ecount for the appearance of the disease in tree and 
arub species not previously attacked by it. It seems 
7 
likely that the continued indiscriminate movement of 
nursery stock from one region to another will eventual- 
ly bring about a complete distribution of all virulent 
strains to areas where they did not exist before. 
TasLEe 3.—Symptoms of Verticillium wilt observed on trees and shrubs. 
Host Plant 
Ash 
Azalea 
Boxwood 
Catalpa 
Coffee tree 
Cork tree 
Elm 
Goldenrain tree 
Linden 
Locust, black 
Magnolia 
Maple 
Oak 
Pagoda tree 
Redbud 
Rose daphne 
Russian olive 
Smoke tree 
Sour gum 
Sumac 
Tulip tree 
Viburnum 
Yellowwood 
TERATURE CITED 
RMSTRONG, NEWTON G. 
1941. 
Type of Decline 
Leaf Symptoms 
Twig or branch dieback. 
Young trees usually appear to 
recover. 
Usually rapid decline, 2-4 weeks. 
Shrubs usually die. 
Twig dieback. Some plants may 
recover. 
Twig or branch dieback; occa- 
sionally branches or whole 
tree wilts. Trees appear to re- 
cover. 
Twig dieback. Young seedlings 
recover. 
Branch wilt. Young trees appear 
to recover. 
Twig dieback. Sometimes whole 
tree dies. 
Usually rapid decline, 2-4 weeks. 
Young trees may recover. 
Usually branch dieback. Some 
trees may recover. 
Twig dieback. 
Usually rapid decline; sometimes 
only branches are affected. 
Varies with species from rapid 
to no decline. Symptoms may 
disappear and reappear years 
later. 
Twig dieback, slow decline 
Slow decline, 1-2 years. 
Usually rapid decline, 2-4 weeks. 
Trees usually die. 
Slow decline over 2-3 years. 
Twig dieback; may occur each 
year or skip a year or two and 
reappear. Some trees may die. 
Rapid decline. Trees usually die. 
Usually rapid decline, 2-4 weeks. 
Trees usually die. 
Rapid decline, 2-4 weeks. 
Shrubs usually die. 
Rapid decline, 2-4 weeks. 
Trees usually die. 
Rapid decline, 2-4 weeks. 
Shrubs usually die. 
Rapid decline, 2-4 weeks. 
Trees usually live. 
Verticillium wilt of horse- 
chestnut. Arborist’s News 6:82-83. 
AINES, R. C. 
1945. Verticillium wilt and die-back of Vi- 
burnum. Phytopathology 35:145-147. 
Vascular Symptoms 
in Xylem 
Abscission when still green; 
yellowing and scorching of 
other leaves 
Yellowing and browning 
Browning and defoliation 
Yellowing and scorching 
Yellowing, scorching, and de- 
foliation 
Yellowing and defoliation 
Flaccidity, yellowing, and de- 
foliation 
Scorching and browning 
Yellowing and browning 
Yellowing, browning, and de- 
foliation 
Yellowing, browning, and de- 
foliation 
Scorching, browning, and de- 
foliation 
Flaccidity, discoloring, brown- 
ing, and some defoliation; 
similar to oak wilt. 
Yellowing and browning 
Flaccidity, yellowing, brown- 
ing, and some defoliation 
Yellowing and defoliation 
Yellowing and browning 
Margins reddish-purple; later 
yellowing, browning, and 
defoliation. 
Scorching and browning 
Yellowing and browning 
Yellowing and defoliation 
Browning and defoliation 
Browning and defoliation 
Faint tan streaks (when they 
occur); seldom found in 
twigs. 
Yellowish-brown to brownish- 
black streaks 
Brown discoloration 
Purplish-pink to bluish-brown 
upon drying 
Light brown streaks 
Faint brown streaks 
Brown streaks 
Brown streaks 
Brown streaks 
Light to dark reddish-brown 
streaks 
‘Greenish-brown streaks 
Light to dark green streaks; 
often difficult to find. 
Brown streaks and sometimes 
bands; similar to condition 
caused by oak wilt. 
No discoloration observed. 
Brown streaks 
Brown streaks 
Brown streaks 
Yellowish-brown to brownish- 
black streaks 
Chocolate brown streaks 
Light green streaks 
Greenish-brown streaks. Bark 
may be killed in strips on 
trunk. 
Light to dark reddish-brown 
streaks 
Brown streaks 
Baker, K. F., W. C. Snyper, and H. N. Hansen. 1940. Some 
hosts of Verticillium in California. Plant Disease Reporter 
24:424-495, 
BEDWELL, J. L., and T. W. Cuixps. 
1938. Verticillium wilt 
of maple and elm in the Pacific Northwest. Plant Disease 
Reporter 22:22-23, 
