DISEASES OF PLANTS. 155 



On the control of the heart or dry rot of sugar beets, G. Labbe (Btil. Assoc. 

 Chim. 8ucr. et Distill., 28 {1910), No. 1-2, pp. 119-131, fig. 1).—The results are 

 given of various experiments with different fertilizers, lime, soot, ashes, etc., on 

 the control of the heart or dry rot of beets. 



It is claimed that on the addition of nitrogenous fertilizers alone the disease 

 increased, and that it is more intense during dry periods and is less active on 

 plants with low sugar content. It is suggested that the addition of phosphoric 

 acid, humus, and lime in various forms, would be of great value, both chem- 

 ically and in putting the soil in a better physical condition. 



Tables are given showing results obtained from the use of different sub- 

 stances, such as fertilizers, in controlling this disease. 



Tomato diseases, H. W. Barre (South Carolina Sta. Bui. 153, pp. 31-36). 



A preliminary account is given of observations on a number of diseases of 

 tomatoes, together with suggestions for their control, where definite means are 

 known. 



Among the diseases described are the shedding of blossoms and the cracking 

 of fruit, due to environmental conditions; leaf blight (Alternaria solani), leaf 

 spot (Septoria lycopersici) . and leaf mold (Gladosporimn fulvmn), in which 

 the fungi attack the foliage; point rot or blossom end rot, due to Fusarium 

 solani and Macrosporium fasiciilata; ripe rot (Colletotrichiim lycopersici) of 

 the fruit; and bacterial wilt (Bacterium solanacearum) and fungus wilt 

 (Fusarium sp.), which attack the entire plant. 



The prevalence of certain parasitic and saprophytic fungi in orchards, as 

 determined by plate cultures, F. A. Wolf (Plant World, 13 (1910), Nos. 7, 

 pp. 164-172, fig. 1; 8, pp. 190-202, figs. 2). — For these experiments trap cul- 

 tures of glucose agar were placed on the ground during September to May, 

 inclusive, at three different localities in an orchard at the Nebraska state 

 farm. Trap cultures were also made from experiments in an old orchard and 

 compared with those obtained in a new one. At one of the stations the 

 ground cover was clover and alfalfa, and at another millet stubble, while 

 the third was on absolutely clean, cultivated ground. 



It was found that the greater number of forms present in orchards during 

 this time were saprophytes, the most common being Alternaria sp., Clado- 

 sporixmi sp., and PenicilUum expansum, while Phyllosticta Unvitata, a parasite 

 producing leaf spot of apples, was present in abundance during the entire 

 winter, regardless of temperature. Nummularia discreta, although the fruits 

 were mature, did not disseminate its spores in May, while at no time ( Septem- 

 ber to May, inclusive) were viable spores of SpJiwropsis malorum present 

 in the atmosphere of the orchard. 



The total number of spores in the air of an orchard was influenced by the 

 ground cover, being less in well-kept orchards and more in neglected ones. 



Bitter pit of the apple, I. B. P. Evans (Transvaal Dept. Agr., Tech. Bui. 1, 

 pp. 18, pis. 5). — ^An extended account is given of the prevalence of the disease 

 in South Africa, the varieties of apples affected, its characteristics, causes, 

 and probable remedies. 



All imported varieties were found more or less subject to this disease, while 

 two native seedlings (known locally as Koo and Wemmers Hoek) were prac- 

 tically immune. 



A microscopical examination of the spots failed to show the presence of any 

 causal fungi or bacteria, but did show that the brown spots arise in close 

 connection with the vascular bundles, especially at the ends of the bundles 

 where the cells, being subject to great internal pressure, become enlarged and 

 thick-walled. This pressure is caused by an accumulation of water which 



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