IOO 
Journal of Agricultural Research 
Vol. V, No. a 
in northern Maine during the growing seasons of 1913 and 1914. All 
except two of these became centers for foliage infection, and severe 
epidemics of P. infestans followed. 
Conidia of P. infestans may be borne on the cut surfaces and sprouts 
of tubers when planted under field conditions. As the cut surface corks 
over or the tuber decays, the fructification of the fungus decreases. 
Spores taken from tubers two to three weeks after they were first planted 
showed only limited germinating capacity. No evidence was obtained 
tending to show that the conidia borne in the soil are instrumental in 
starting foliage infection. 
The mycelium of P. infestans spreads most rapidly in the cortical tissues 
of the stem, where it travels up more rapidly than down. 
Epidemics of late-blight may start from a single shoot or hill naturally 
or artificially infected with P.infestans. The infection spreads radially 
from the initial point of infection during the early stages of the develop¬ 
ment of an epidemic. These spots of infection in the fields probably 
come into existence through the planting of seed potatoes infected with 
P. infestans. 
LITERATURE CITED 
(1) Bary, Anton de. 
1861. Die gegenwartig herrschende Kartoffelkrankheit, ihre Ursache und ihre 
Verhiitung. 75 p., 1 pi. Leipzig. 
(2) - 
1863. Recherches sur le d6veloppement de quelques champignons parasites. 
In Ann. Sci. Nat. Bot., s. 4, t. 20, p. 5-148, pi. 1-13. For translation 
see The potato disease. In Jour. Quekett Micros. Club, no. 22, p. 139- 
i 45 - lS 7 3 - 
(3) - 
1865. Neue Untersuchungen liber die Uredineen, insbeso^/-re die Entwick- 
lung der Puccinia graminis und den Zusammenhang derselben mit 
Aecidium Berberidis. In Monatsber. K. Preuss. Akad. Wiss. Berlin, 
Jan., p. 15-49, 1 pi. 
(4) - 
1876. Researches into the nature of the potato-fungus—Phytophthora infestans. 
In Jour. Roy. Agr. Soc. England, s. 2, v. 12, p. 239-269, 8 fig. Re¬ 
printed in Jour. Bot. [London], v. 14 (n. s. v. 5), no. 160, p. 105-126; 
no. 161, p. 149-154. 
(5) Berkeley, M. J. 
1846. Observations, botanical and physiological, on the potato murrain. In 
Jour. Hort. Soc. London, v. 1, p. 9-34, 2 fig. 
(6) Boehm, Josef. 
1892. Vortrag iiber die Kartoffelkrankheit. In Verhandl. K. K. Zool. Bot. 
Gesell. Wien, Bd. 42, Sitzber., p. 23-24. 
(7) Brefeld, Oscar. 
1883. Die Brandpilze. I. 220 p., 13 pi. Leipzig. (His Botanische Unter¬ 
suchungen iiber Hefenpilze. Heft 5.) 
(8) Clinton, G. P. 
1906. Downy mildew, or blight, Phytophthora infestans (Mont.) DeBy., of 
potatoes. II. In Conn. Agr. Exp. Sta., 29th Ann. Rpt., [19041/05,' 
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