DISEASES OF PLANTS. 847 



The character of spore formation, growth of the mycelium, etc., are described 

 at some length. 



The diseases of sugar cane, C. Maublanc (Agr. Prat. Pays Chauds, 10 

 (1910), Nos. 88, pp. J,3-56, fig. 1; 89, pp. 1J,3-1I,8, fig. 1; 90, pp. 232-252, figs. 4; 

 91, pp. 312-320, fig. 1; 92, pp. 379-J,00, figs. J,; 93, pp. 502-506, fig. 1).— This is a 

 discussion of the common diseases of sugar cane, based on the notes of G. Dela- 

 croix, which includes both nonparasitic and parasitic forms and gives the 

 symptoms, causes, and methods of combating each disease when known. 



The following diseases and parasites ai-e noted : Dichotomy of the stem, mal- 

 formation of the internodes, abnormal arrangement of the buds, panachure, 

 chlorosis, torsion of the leaves, " disease of Dongkellan," changes produced by 

 injurious substances in the soil, alterations produced by poisons, gummosis, 

 smut (UsUlago sacchari), rind disease (Colletotrichum falcatum), pineapple 

 disease (Thielaviopsis paradoxa), Coniothyrium sacchari, Lasiodiplodia theo- 

 hromw, root rot (Marasmius sacchari), cane rot {Schizophyllum commime and 

 Tramctes pusilla), Sphwronema adiposum, Cytospora sacchari, Saccharoniyces 

 apiculatus sacchari, bacterial gummosis, point rot, collar rot, sereh (a disease 

 characterized by shortened internodes which crowd the leaves together and 

 cause the young blades at the top to open sooner than on normal plants and to 

 spread out fan-like), leaf-splitting disease, root diseases {IthyphaUus ccleMcus 

 and /. coralloides), Pythium, nematodes, Santalum alhum, Alectra hrasiliensis, 

 rust (Uromyces kUhnii), leaf spot (Cercospora kiipkei, C. sacchari, and 

 C. longipes), red spot of the sheaths (C. vagince), black spot (C. acerosum), 

 ring disease (Leptosphceria sacchari), Venturia sacchari, Sphwrclla striati- 

 forma ns, Phyllachora sp., Pestalozzia sp., sclerotia of the leaves, sheath rots 

 (Sclcrotium spp.), and sooty mold. 



The sereh disease of the sugar cane (Agr. News [Barbados], 10 {1911), No. 

 2Iil, pp. 238, 239). — The symptoms and characteristics of this disease are given, 

 together with a discussion of its probable cause. It is claimed that no known 

 organism has as yet been shown to be the cause of this disease. 



Tomatoes and Irish blight, D. McAlpine {Jour. Dept. Agr. Victoria, 9 

 (1911) , No. 6, pp. 379-382, fig. 0-— Attention is called to the infection of toma- 

 toes, especially of the fruits, by the late blight from adjacent diseased potato 

 plants. The results are also given of cross inoculation experiments on both the 

 tomato and potato with the spores of this fungus. 



It was found that tomatoes and potatoes are mutually infected, and that even 

 with the tough skin unbroken, spores falling on them when moist can cause 

 infection, producing a fresh crop of spores within 9 days. 



Some frost injuries of fruit trees, G. LiJSTNER (Deut. Obstbau Ztg., 1911, No. 

 14, pp. 233-236, figs. 5). — Descriptions are given of frost injuries to the leaves 

 of apples, pears, and raspberries, due to late freezes in which the temperature 

 fell from 2 to 6° below the freezing point during the month of April. 



A new disease of apples, J. P. Stewart (Pennsylvania Sta. lipt. 1910, pp. 

 267, 268, pL 1). — A description is given of a new disease of apples, which is 

 apparently due to physiological disturbances, its most conspicuous characters 

 being shown in the twigs of the current season's growth. These twigs lose their 

 normal color and become dull, blistered, and mottled, and at a casual glance the 

 effect somewhat resembles that produced by the San Jose scale. Immediately 

 under the epidermis of the diseased areas and extending about halfway to the 

 cambium may be seen numerous small brown spots where the tissues are dead 

 or dying. Later, on the surface, the epidermis cracks around and over the 

 diseased spots, and they become rough, scablike, and slightly sunken through 

 the drying out and death of the tissues beneath. In some cases the cracks go 

 deeper and involve the wood. The leaves are affected sooner or later, probably 



