DISEASES OF PLANTS. 49 



29, p. 347), citing also views of other investigators regarding leaf roll of 

 potatoes. 



The persistence of the potato late blig-ht fungus in the soil, F. C. Stiwabt 

 (New York State Sta. Bui. 367, pp. S57-S61). — On account of conflicting state- 

 ments regarding the persistence of the fungus Phytophthora infestans in the 

 soil and the discovery of the oospores of the potato blight (E. S. R., 25. p. 

 545), the author carried on experiments in soil from a field in which a large 

 portion of the potato crop had been destroyed by the Phytophthora rot. The 

 soil together with a quantity of blighted potato stems was phiced in wooden 

 boxes, which were left in the field until late in January when they were brought 

 into. the greenhouse and planted to potatoes. A second experiment, which was 

 practically a repetition of the first with some modifications, was conducted, but 

 the results were negative in each case. 



The conclusion is reached that while the negative results do not prove that the 

 Phytophthora does not persist in the soil, they make such persistence appear 

 highly improbable, and the removal of diseased tubers from the field, as recom- 

 mended by Massee (E. S. R., 17, p. 45), is considered unnecessary. While the 

 planting of potatoes after potatoes is said to have a tendency to increase scab, 

 wilt, and other diseases, it is believed that there is no risk in the practice bo 

 far as the late blight or rot is concerned. 



Does winter kill potato blight in the soil? F. H. Hall (New York State Sta. 

 Bui. 861, popular ed., p. 1). — This is a popular edition of the above. 



Potato spraying experiments in 1911, N. J. Giddings {West Virginia Sta. 

 Rpt. 1912, pp. 77, 78). — An account is given of experiments conducted at Mounds- 

 ville, W. Va., during 1911 with the object of determining the relative value of 

 Bordeaux mixture when prepared by various methods of mixing or by using 

 formulas other than those commonly employed. Atomic sulphur was also tested 

 as a spray for potatoes. 



The weather during the early part of the season was exceedingly dry and 

 hot, and many of the plants were destroyed. The results as to spray mixtures 

 are not considered of any special value, as it was impossible to get the potatoes 

 sprayed at a time when they were most seriously in need of it. 



Ufra disease of rice, E. J. Butlfr {Agr. Jour. India, 8 {WIS), No. S, pp. 

 205-220, pi. 1, fig. 1). — In continuation of a preliminary note (E. S. R., 28, p. 

 151), a detailed account is given of a study of this rice disease in India. 



Two distinct manifestations of the disease are described, and it has been defi- 

 nitely determined that it is due to Tylenchus sp. The occurrence of this disease 

 has been known for a number of years, but only recently has it become very 

 destructive, losses of from 10 per cent to total destruction of fields having been 

 reported. 



The different crops of rice are said to be affected in unlike manner, and 

 transplanted rice seems practically free from attack. A lack of aeration of the 

 soil is thought to favor the attack of the nematodes, but other considerations, 

 among them the accumulation of nitrites, must be taken into account in plans 

 for the control of this disease. A special grant has been made in Bengal for 

 extensive experiments on means for its control. 



Notes on sereh disease of sugar cane, S. F. Ashby {Bui. Dept. Agr. Jamaica, 

 n. ser., 2 {1913^, No. 7, pp. 239, 240, pi. 1). — On account of the suspected oc- 

 currence of the serch disease of sugar cane in Trinidad, the author gives a de- 

 Bcription of the external and internal appearances of diseased cane. Two views 

 are held regarding the cause of this disease, one that it is due to a gum-form- 

 ing bacterium, and the other that it is caused by a lack of balance in enzym 

 action within the living cells of the plant, brought about by abnormal condi- 

 tions of the soil, cultivation, manuring, etc. 



