No. 3, April, 1921] PATHOLOGY 291 



THE HOST (RESISTANCE, SUSCEPTIBILITY, MORBID ANATOMY AND 



PHYSIOLOGY) 



2029. Bakke, A. L. The comparative rate of desiccation of tubers from normal and dis- 

 eased potato plants. Phytopath. 9:541-546. 1 fig. 1919. — The moisture losses of Rural 

 New Yorker and Eureka potato tubers from healthy plants and from plants showing the curly- 

 dwarf disease were studied under storage conditions. The tubers from diseased plants on 

 being desiccated reached an equilibrium with the evaporating power of the air sooner than 

 did tubers from healthy plants of the same variety. This increased water loss from diseased 

 tubers was due to the development of fissures in the suberized epidermis. The curly-dwarf 

 tubers when completely dried showed a greater water absorbing capacity than desiccated 

 normal tubers under similar conditions. — J. G. Dickson. 



2030. Shapovalov, M., and H. A. Edson. Wound-cork formation in the potato in 

 relation to seed piece decay. Phytopath. 9:483-496. 3 fig. 1919. — The writers show that 

 sprouting alone does not affect the ability of potato tubers to form cork over wound surfaces, 

 but that the drying or shriveling of the tissues, which usually accompanies germination when 

 in warm storage, checks rapid cork formation over cut surfaces. They further demonstrate 

 the general susceptibility of badly shrunken tubers to attack by decay producing organisms 

 in the soil. The resistance of the seed piece to attacks diminishes in direct proportion to the 

 water loss from the tuber. A shriveled tuber must first imbibe the necessary water from the 

 soil before it is able to initiate cell division; consequently, destructive activities of micro- 

 organisms develop so rapidly that formation of the protective cork layer in the shriveled 

 tubers comes too late to check invasion. Proper storage conditions for seed potatoes — a 

 reasonably low temperature and suitable humidity to prevent excessive evaporation — will 

 control the seed piece rot under generally existing conditions. — /. G. Dickson. 



2031. Stoklasa, Jules. Action de I'acide cyanhydrique sur I'organisme des plantes. 

 [The effect of hydrocyanic acid on the plant organism.] Compt. Rend. Acad. Sci. Paris 170: 

 1404-1407. 1920. — Quantities up to 4 per cent (by volume) of hydrocyanic acid were tested. 

 With Tilletia tritici, 1 per cent reduces and 2 per cent strength prevents spore germination. 

 Other microorganisms tried showed greater resistance, e.g., Bacillus subtilis and B. mesen- 

 tericus vulgaius which resist 3 per cent and Aspergillus which will withstand 4 per cent. 

 Mucor and Penicilliiim are killed by 3.5 per cent. This gas is found valuable in disinfecting 

 seeds, as 1 to 2 per cent while reducing infection does not hinder wheat germination. 

 It is necessary to dry the seeds in the open air for 3 days before attempting to germinate 

 them. — C. H. Farr. 



DESCRIPTIVE PLANT PATHOLOGY 



2032. Afonso, Pedro Correia. Algumas doencas do arroz. [Some diseases of rice.} 

 Bol. Agric. Nova Goa [Portuguese East India] 1 : 113-128. 7 fig. 1919.— A brief description of 

 certain of the more serious rice diseases of British India which might be introduced with 

 seed grain. — John A. Stevenson. 



2033. Anonymous. Silver leaf disease. Jour. Roy. Hort. Soc. 45: 313-315. 1919. 



2034. Atanasoff, Dimitr. Fusarium-blight (scab) of wheat and other cereals. Jour. 

 Agric. Res. 20: 1-32. 1920.— The chief cause of "scab," or headblight, and one of the chief 

 causes of rootrot of the cereal crops in the central and eastern cereal growing regions of the 

 United States is a Fusarium known in its ascigerous form as Gibberella saubinetii. However, 

 in fewer cases headblight is caused by each of nine other species and rootrot by four other 

 species of Fusarium. Gibberella saubinetii attacks either the roots, causing rootrot, or the 

 stems and head, causing scab. The present paper deals primarily with the latter condition. 

 A careful description of the blighting of each stage of the host is given. In the case of the 

 blighting of the heads, it was found that the infection was first detected three to four days after 



BOTANICAL ABSTRACTS, VOL. VII, NO. 3 



