DISEASES OF CULTIVATED PLANTS 443 
appears to be the same as that attacking the greenhouse seedlings of lettuce 
tomatoes, 'etc., (hizoctonia sp.) and‘can apparently be reached only by similar 
methods. 
Beet Scab affects the roots of the beet as the scab does potato tubers. It is 
thought to be due to the same organisms. It may be avoided largely by avoid- 
ing the conditions for scab already mentioned under ‘potato scab. Rotation of 
sugar beets will probably be required to escape this and other diseases. 
SWEET POTATO 
Bin or Soft-Rot is encountered by the sweet potato growers. The fungus 
(Rhizopus nigricans Ehrh.) producing it may be present in the plant bed and 
apparent as dark spots or rotted tips on the plants at setting. All such plants 
ought to be discarded if avoidance of disease is sought. Some experiments 
were made at Marietta in 1897, to prevent or reduce this rot, but without posi- 
tive advantage in the keeping qualities. A dope or mixture Of 6 parts earth to 
one part flowers of sulfur was dropped in handfuls and the plants set through 
the mixture thus bringing it about the roots of the plants very nicely. Smoother 
potatoes were obtained and these separated more readily from adherent earth, 
but no better keeping qualities resulted for that year. The potatoes were har- 
vested, however, during a wet period and conditions were less favorable than is 
often the case. 
Soil-Rot (Acrocystis Batatas Ell. & Hals.) isa serious disease of sweet 
potatoes for which the above described treatment has proved successful in New 
Jersey. (N. J. Exp. Sta. B. 126). 
Stem-Rot (Vectria Ipomoeae Hals.) attacking the stems and roots has 
appeared in Ohio sweet potato fields, apparently introduced by affected seed. 
Such seed should be avoided. Rotation may also be necessary. 
White Mold or White Rot (Cystopus [pomoca-panduranae (Schw.) Farl.) is 
rommon upon the Man-of-the-earth and the wild morning glory (Convolvulus 
hederaceae) in the sweet potato districts, but apparently is not frequent upon 
sweet potato foliage. 
Black-Rot. This disease of sweet potato roots shows in dark, somewhat 
sreenish spots of varying diameter. It causes serious losses in the roots and 
rom diseased potatoes gives ‘‘black shank’’ in great abundance upon the young 
plants. The fungus (Ceratocystis fimbriata Ell. & Hals.) has been described as 
a result of Dr. Haisted’s work in New Jersey. In treatment the measures are 
largely preventive in the choice of healthy seed, healthy sprouts and the sterili- 
zation of the plant beds. 
SWEET CORN 
Bacterial Disease has at times proved serious in sweet corn fields, but is 
apparently the same in character as that attacking sorghum, broom corn and 
field corn. 
Smut (Ustilago Zeae Beckm.) also attacks sweet corn and where crops are 
grown consecutively in garden, the amount is sometimes excessive. The cause of 
it is the same as that of field corn and the conditions of control are the same. 
SYCAMORE 
Anthracnose (Gloeosporium nerviseguum (Fckl.) Sacc.) is periodically very 
destructive on the foliage of the sycamore, extending at times to the younger 
shoots. The warm wet springs appear to be favorable to it; such was notice- 
ably the case in 1908 and again in 1909. The outbreak in these years extended 
all over eastern United States. While the disease should be amenable to fungi- 
cides, it has been neglected. 
