170 PATHOLOGY [BoT. Absts., Vol. VII, 



THE PATHOGENE (BIOLOGY, INFECTION PHENOMENA, DISPERSAL) 



1139. BisBY, G. R. Studies of Fusarium disease of potatoes and truck crops in Minne- 

 sota. Minnesota Agric. Exp. Sta. Bull. 181. 58 p., 11 pi., SO fig. Mar., 1919.— Fusarium 

 oxysporum is the cause of potato wilt. It may attack any part of the potato plant and may 

 cause rot of the seed tuber under field conditions. In the fall it may attack plants which have 

 previously produced a normal crop of tubers. Tubers from affected plants are less satis- 

 factory for planting than those from healthy plants. Any measures which tend to keep the 

 plants vigorous, particularly during the latter part of the season, lessen the danger of wilt. — 

 Fusarium discolor sulphureum gains entrance through wounds or through the uninjured sur- 

 face, and causes dry rot in storage potatoes. Tubers from normal potato vines are subject 

 to this rot. None of the varieties tested were resistant to this dry rot. It may develop on 

 unsprouted tubers even under dry conditions at temperatures below 2°C. At temperatures 

 below 16°C. this fungus produces abundant aerial mycelium, and at 20° to 30°C. a dense 

 pseudopionnotes. This fungus does not affect the starch grains. Wilt in potato plants is 

 not produced, but affected tubers may produce weak sprouts or none. — Careful handling to 

 avoid injury and cleanliness in storage houses are important measures in avoiding injury 

 by rot. The indications are that wilt- or root-rot-producing species of Fusarium may 

 show a selective tendency toward host plants. No single species of Fusarium is responsible 

 for storage rots in vegetables, cucumbers, and tomatoes. Species of Fusarium were found 

 to produce substances that inhibited the germination of spores of the same or other species. 

 After being boiled, solutions of these substances allowed normal germination. Fusarium 

 produced substances injurious to excised leaves of potato, coleus, and ragweed. Boiling 

 did not destroy this property. The species of Fusarium examined could withstand drying, 

 low temperatures, and alternate thawing and freezing. They were able to utilize a wide 

 variety of food substances. — A. C. Amy. 



1140. Clinton, G. P., and McCormick, Florence A. Artificial infection of pines with 

 Cronartium ribicola. Amer. Plant Pest Committee Bull. 4: 12. 1920.— Same work as re- 

 ported in Connecticut Agric. Exp. Sta. Bull. 214: 428-459. PI. 37-43. 1916-1918.— See Bot. 

 Absts. 6, Entry 225. 



1141. Dastur, J. F. The mode of infection by smut in sugar cane. Ann. Botany 34: 

 391-397. Fig. 1-10. 1920.— Experiments with sugar-cane smut ( Ustilago sacchari) showed 

 that infection takes place in susceptible "thin" varieties through the tender buds, but not 

 through old buds unless wounded. The infecting germ tube was found to enter the host 

 tissues through unthickened scale hairs. Infection did not occur through the cut ends of the 

 sets. "Thick" varieties of cane were only infected through wounded tender buds.— R^ P. 

 Fraser. 



1142. Jensen, C. N. Blossom infection by smuts. Utah Acad. Sci. 1: 106-113. 1918.— 

 Paper presented to the Academy, April, 1913. A review of the work of Brefeld on infection 

 processes in the Ustilagineae. — D. Reddick. 



1143. KuNKEL, L. O. Further data on the orange rusts of Rubus. Jour. Agric. Res. 19: 

 501-512. PI. D {colored) and 92-94. 1920.— See Bot. Absts. 7, Entry 367. 



1144. Schweizer, Jean. Die Spezialisation von Bremia lactucae Regel. [Specialization 

 of B. 1.] Verhandl. Schweiz. Naturf. Gesell. 99: 224. 1918.— Abst. in Zeitschr. Pflanzenkr. 

 30:24. 1920. 



1145. TocHiNAi, YosHiHiKo. Studics on the food relations of Fusarium lini. Ann. 

 Phytopath. Soc. Japan P: 22-33. 1920.~See Bot. Absts. 7, Entry 419. 



1146. Treherne, R. C. Synopsis Report of the Dominion Entomological Branch in British 

 Columbia. Dept. Agric. British Columbia Ann. Rept. 14:49-53. 1920. [Also Agric. Jour. 

 British Columbia 5: 25-29.]— Includes observations on insect carriers of fire blight (Bacillus 



