76 PATHOLOGY [BoT. Absts., Vol. VIII, 



fungi; (3) a search for possible criteria by which parasitic attacks on wood may be distin- 

 guished from saprophytic action. The particular type of decay in timber due to F. applana- 

 tus has now by actual culture been linked with its causal agent. The species has been proved 

 to be a wound parasite, in southern Ontario one of the commonest and most destructive. 

 The occurrence of wound gum and the multiplication of tyloses in a band marking the advance 

 of a wood destroying fungus in a living tree would appear to furnish an unerring criterion 

 for the recognition of a fungus as a parasite. — R. B. Thomson. 



522. WiLTSHiEE, S. P. The apple canker fungus. Ann. Rept. Agric. and Hort. Res. 

 Sta. Univ. Bristol 1919: 23-29. 1919. — Nectria ditissima ejects its ascospores so that pure 

 cultures were obtained by the inverted plate method. Mature perithecia were secured on 

 malt extract agar in tubes. — Critical temperatures for the fungus in culture are: Minimum 

 about 5°, optimum, 20-22°, maximum about 30°C. — Infection through young buds was very 

 abundant in 1918. The spores and mycelium were found abundantly on bud scales in Sep- 

 tember but it is not yet established that the fungus penetrates in the absence of injury. In- 

 fections about galls produced by woolly aphis were confined to those that had broken open. — 

 D. Reddick. 



DESCRIPTIVE PLANT PATHOLOGY 



523. Anonymous. Gulbladede Hortensier. [Yellows of Hydrangea.] Gartner-Tidende 

 [K^benhavn] 36: 139. 1920. — Hydrangea should be planted in rather light soil not too rich 

 in manure. The yellows may be caused by too heavy soil, presence of manure, drought, or 

 starvation. — Ernst Gram. 



524. Bennett, C. W. Phoma root-rot of celery. [Abstract.] Phytopath. 10: 67. 1920. 



525. Brown, Nellie A., and R. B. Harvey. Heart rot, rib rot, and leaf spot of Chinese 

 cabbages. Phytopath. 10: 81-90. 4 fig- 1920. — The Chinese cabbage (Brassica pekinensis 

 and B. chinensis) is subject to the black rot disease of the common cabbage produced by Bac- 

 terium campestre, and, as in the common cabbage, there may be also a rapid secondary infec- 

 tion by a soft rot organism. High temperature and excessive moisture favor the develop- 

 ment of the disease. Control measures are suggested. — J. G. Dickson. 



526. Burger, O. F. Decay in citrus fruits during transportation. Monthly Bull. Dept. 

 Agric. California 9: 365-370. 1920. — Lemon decay (due to Phomopsis ciiri), a disease new to 

 California lemons, was found in California during the season 1919-20. The writer discusses 

 the economic importance of stem-end rot and blue-mold decay on citrus fruits in transpor- 

 tation. Stem-end rot infection takes place in the field. To insure sound fruit the disease 

 should be eliminated from the groves. Proper methods of handling, packing, and shipping 

 are given for blue-mold decay control. — E. L. Overholser. 



527. Byars, L. p. A disease of red clover and strawberry in the Pacific Northwest caused 

 by the nematode Tylenchus dipsaci (Kiihn) Bastian. [Abstract.] Phytopath. 10: 66. 1920. 

 —See Bot. Absts. 8, Entry 528. 



528. Byars, L. P. A nematode disease of red clover and strawberry in the Pacific North- 

 west. Phytopath. 10:91-95. 2 pi. 1920. — A disease caused by Tylenchus dipsaci is 

 described. [See Bot. Absts. 8, Entry 527.] — J. G. Dickson. 



529. Chen, Chunjen C. [A study of American cotton diseases.] Hua-Shang-Sha-Chang- 

 Lien-Ho-Hui-Ki-Kau [China Cotton Jour.] 1'': 245-256. 1920. — The cause, symptoms, means 

 of transmission, and control of the following important cotton diseases are reviewed : Angular 

 leaf spot, anthracnose, wilt, root-knot, potash-hunger, damping-off, root rot, Diplodia boll 

 rot, shedding of bolls and squares, and leaf spot. The reduction in cotton yield in the United 

 States due to diseases is discussed and statistics are given. The author also points out the 



