19171 DISEASES OF PLANTS. 657 



the investigation of the lemon brown rot fungus, the author reports having 

 isolated from gumming citrus trees an organism which, when inoculated upon 

 healthy lemons, developed a brown rot similar to that produced by Pythiacystis 

 citrophthora. 



The ori^n and cause of citrus canker in South Africa, Ethel M. Doiuge 

 (Union So. Africa Dept. Agr., Set. Bui. 8 (1916), pp. 20, pis. 10, figs. S; ditto, Div. 

 Bot. [Pub.] 20 (1916), pp. 8, pis. 6).— Citrus canker, claimed by Hasse (E. S. 

 R., 33, p. 149) to be caused by an organism described by her as Pseudomonas 

 citri, but designated by the present author as Bacterium citri, is said to have 

 been imported on grapefruit trees from Florida. A brief history of the disease 

 In Africa and elsewhere is given, with an account of study by the author. 



At first the trouble was taken to be a severe outbreak of scab (Cladosporium 

 citri). Serious effects may be produced even in the nursery. The organism 

 works in buds, leaves, fruits, and branches. Orange, lime, and related plants 

 are attacked. It is claimed that under the dry conditions of the Transvaal the 

 disease has been effectively controlled with a 4 : 4 : 50 Bordeaux spray. This 

 should be used two or three times the first year v/ith a single spraying every 

 year or two thereafter. Badly infected stock should be burnt and old cankers 

 should be searched for, as infection may occur after four years of apparent 

 freedom from canker. 



Anaberoga, M. K. Venkata Rao (Mysore Agr. Calendar, 1917, pp. 26, 27, SO, 

 fig. 1). — Anaberoga of the areca palm in parts of Mysore is described in con- 

 nection with the fungus locally known as " anabe," which attacks trees, 

 usually over 10 years of age, at the roots and collar and apparently spreads 

 through the soil and by air-borne spores. Other plants of different genera, 

 and even different orders, are also attacked by the fungus, which causes the 

 same general symptoms, ending in the death of the tree. No remedial measures 

 are effective after the tree is attacked. 



Diseases and pests of the mango, K. Kxjnhikannan and C. Noronha (My- 

 sore Agr. Calendar, 1917, pp. 7, 10, 11, figs. S). — Failure of mango trees in My- 

 sore to set fruits has been shown by recent observations to be due to a fungus 

 which attacks young leaves and flower spikes. It develops most rapidly under 

 moist conditions, the drying up of the flowers following a succession of misty 

 or damp nights. This fungus is distinguished from other local mildews which 

 attack tobacco and roses. Bordeaux mixture applied to the young leaves and 

 flower spikes just before the blooms open controls the disease. A combined 

 treatment is being sought for both fungi and troublesome insects, some of 

 which are mentioned in this article. 



Powdery mildew of dwarf magnolias, M. Tubconi (Riv. Patol. Veg., 7 

 (1915), No. 6, pp. 164-167). — The disease produced by species of Erysiphe on 

 several plants is said to be associated in the case of Magnolia pumila with a 

 fungus, the characters of which, as described, are considered to agree v^dth 

 those of E. polygoni. 



Black canker of chestnut, B. Petronel (Atti R. Accad. Lincei, Rend. CI. Sci. 

 Fis., Mat. e Nat., 5. ser., 25 (1916), II, No. 11, pp. 459-461).— This is a pre- 

 liminary discussion of a study of black canker of chestnut, now becoming im- 

 portant in Italy, its manifestations, the causal or contributing agents (such as 

 atmospheric conditions), and various related problems, such as the mode of 

 penetration by the fungi, no trace of which appears outwardly in the early 

 stages of the disease. 



Black canker of chestnut, L. Petri (Atti R. Accad. Lincei, Rend, CI. Sci. Fis., 

 Mat. e Nat., 5. ser., 25 (1916), II, No. 5, pp. 172-176, figs. 2).— Previous r^orts 

 on black canker of chestnut (E. S. R., 33, p. 854; 35, p. 250) are continued. 



