266 PATHOLOGY [Bot. Absts.. Vol. V, 



surface of the bulb shows the presence of numerous black spherical sclerotia about the size 

 of small poppy seed (0.5 mm. in diameter). The sclerotia appear to persist in the soil at least 

 three or four years and may survive considerably longer. The disease is introduced into new 

 localities by contaminated soil and manure, diseased seedlings and "sets." All common vari- 

 eties are susceptible. Shallots are usually very resistant as is also true of leeks. The only 

 present known means of control is to keep the infected ground free from onions and allied crops 

 for a number of years. Soil fungicides have not proved effective. — M. B. McKay. 



2029. Culham, A. B. Report on the agricultural station, Aburi. Rept. Agric. Dept. Gold 

 Coast 1917: 24-29. 1918. — Includes a note, with table, on distribution of cocoa diseases. — 

 .7. 7. Lauritzen. 



2030. Darnell-Smith, G. P. An account of some observations upon the life-history of 

 Phoma citricarpa McAlp. The cause of the "Black Spot" disease in Citrus fruit in New South 

 Wales. Proc. Linnean Soc. New South Wales 43 : 868-882. PI. 84-90. 1918.— The paper first 

 presents a brief historical review of the fungus and the disease. This is followed by a state- 

 ment of the general symptoms. The disease is serious in New South Wales, producing 

 minute black spots on the foliage throughout the year. On the fruits the spots are rarely seen 

 before the first of August, and vary from | to \ inch or more in diameter. The disease appears 

 almost invariably on the sunny side of the tree and on the side of the fruit exposed to the 

 sun. This has been checked up experimentally and is explained as being due to the lowering 

 of vitality by action of the sun. — Culture data are given and the structure of the mycelium, 

 spores and pycnidia discussed. Two types of spores were found, large viable ones and smaller 

 ones, termed "X" spores, which do not germinate. — The disease can be controlled with 

 Bordeaux. — C. J. Humphrey. 



2031. Doidge, Ethel M. The role of bacteria in plant diseases. [Presidential Address, 

 South African Assoc. Adv. Sci., Kingwilliamstown, July, 1919.] South African Jour. Sci. 16: 

 65-92. 1919. — This is a review of the history of plant bacteriology and a summary of 

 present knoweldge of the role of bacteria in plant diseases with special reference to South 

 African conditions and to diseases of plants occurring in South Africa. — E. M. Doidge. 



2032. Duysen, F. Wurzelbrand im Weizenschlage. [Root-scald in wheat-fields.] Illus- 

 trierte Landw. Zeitg. 39: 372-373. 1919. — The diseases caused by the fungus, Leptosphae- 

 ria culmifraga, is described and indirect control through increasing the resistance of the host 

 plant by proper fertilization is recommended. Badly diseased fields should be plowed up and 

 replanted with crops other than wheat or rye. Such fields should not be planted with wheat 

 or rye for a term of years. — John W. Roberts. 



2033. Eberson, Frederick. A yeast-agar medium for the Meningococcus. [Abstract.] 

 Absts. Bact, 3: 10. 1919.— See Bot. Absts. 5, Entry 1940. 



2034. Ekambaram, T. Suspected parasitism in a moss. Jour. Indian Bot. 1: 206-211. 6 

 fig. 1920. — During the monsoon season a common unidentified moss in Madras is found with 

 its rhizoids and protonemata penetrating colonies of Cyanophyceae. Because the penetrating 

 rhizoids and protonemata are colorless, and become filled with starch coincidentally with the 

 decay of the alga colonies, the author suggests that the moss is parasitic on the algae. Haus- 

 torial connections were not observed. — Winfield Dudgeon. 



2035. Eriksson, Jakob. Sur l'heteroecie et la specialisation du Puccinia caricis, Reb. 

 [On heteroecism and specialization in Puccinia caricis Reb.] Rev. Gen. Bot. 32 : 15-18. 1920. 

 — See Bot. Absts. 5, Entry 645. 



2036. Erwix, A. T. Hot formaldehyde treatment for potato scab. Potato Mag. 2 l0 : r 14. 

 1 fig. 1920. 



