Journal of Agricultural Research 



in northern Maine during the growing seasons of 191 3 and 191 4. All 

 except two of these became centers for foliage infection, and severe 

 epidemics of P. infeslans followed. 



Conidia of P. injestans 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 v/as obtained 

 tending to show that the conidia borne in the soil are instrumental in 

 starting foliage infection. 



The mycelium of P. injestans 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. injestans. 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. injestans. 



LITERATURE CITED 

 (i) Bary, Anton de. 



1861. Die gegenwartig herrschende Kartoffelkrankheit, ihre Ursaclie trnd ihre 

 Verhiitung. 75 p., i pi. Leipzig. 



(2) 



(3) 



Recherches sur le developpement 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- 



145- 1873. 



[S65. Neue Untersuchxmgen iiber die Uredineen, insbesondere die Entwick- 

 lung dcr Puccinia graminis und den Zusamraenhang derselben mit 

 Aecidium Berberidis. In Alonatsbcr. K. Preiiss. Akad. Wiss. Berlin, 

 Jan., p. 15-49, I 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 iyi Jour. Bot. [Londoa], v. 14 (n. s. v. 5), no. 160, p. 105-126; 

 no. 161, p. 149-154. 



(5) Berkeley, m. j. 



1S46. Observations, botanical and physiological, on the potato murrain. In 

 Jour. Hort. Soc. London, v. i, 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) Brekeld, Oscar. 



1883. Die Brandpilze. I. 220 p., 13 pi. Leipzig. (His Botanische Unter- 

 suchungen iiber Hefenpilze. Heft 5.) 



(8) CuXTO.Nf, G. P. 



1906. Do-\\-ny mildew, or blight, Phytophthora infestans (Mont.) DeBy., of 

 potatoes. II. In Conn. Agr. Exp. Sta., 29th Ann. Rpt., [i 9041/05 , 

 p. 304-330, pi. 23-25. 



