DISEASES OF PLANTS. 137 



being caused by attacks of wireworms, millepeds, and injuries caused 

 by wliite grubs and small mammals, such as field mice, etc. The scab 

 caused by Oospora scabies is also figured and described. Plat experi- 

 ments were conducted to test the value of Bordeaux mixture and corro- 

 sive-sublimate solutions for preventing scab. The injury done by the 

 fungus on both treated and untreated plats was so slight as to give 

 but little opportunity for comparison. The tubers were soaked in Bor- 

 deaux mixture aud corrosive-sublimate solutions, and in one plat they 

 were sprayed with Bordeaux mixture in the rows before covering. The 

 use of Bordeaux mixture for soaking the seed seemed to have no bene- 

 ficial actioii. The results with the corrosive-sublimate solution were 

 suf&cient to warrant the author recommending this treatment for scab 

 prevention. 



Potato scab, L. Foster {Montana Sta. Bui. 9, pp. 5,2-^i).— Notes are 

 given on experiments for the prevention of potato scab. A tabulated 

 report is given of the results obtained by using zinc chlorid, zinc sul- 

 phate, potassium permanganate, potassium bicarbonate, potassium 

 sulphid, and corrosive sublimate in different strengths of solution aud 

 for difierent lengths of treatment. The different compounds in some 

 strength were somewhat effective in reducing scab, but the corrosive- 

 sublimate treatment, when the seed tubers had been treated for at least 

 an hour, proved the most successful treatment. 



Diseases of the potato, E. G. Lodeman {New YorJc Cornell Sta. 

 Bui. 113, pp. 2d9-.3S3, pi. 1, figs. 3). — Popular notes are given on the late 

 blight or rot, the early blight, and scab of potatoes, together with notes 

 on the injurious insects affecting the i^otato, and recommendations for 

 the prevention of the several injuries. 



The potato rot, or late blight, which is due to Fhytoplitliora infestans, 

 is fully described, and it may be successfully prevented by spraying the 

 vines with Bordeaux mixture. In giving the life history of this fungus 

 the author mentions oospores as a means for carrying it over the winter. 

 W. G. Smith ^ claimed that these bodies have been observed, but 

 De Barry and others do not accept his conclusions. 



The early blight, which has been recognized but a few years as dis- 

 tinct from the late blight, is usually attributed to attacks of Macrospo- 

 rium solani, but recent investigations show a number of causes at work 

 to produce the condition called early blight. These causes may be the 

 fungus, peculiar character of the season, injuries of flea beetles, or some 

 disturbance in tlie physiological functions of the plant. Each of these 

 or several of them acting together may produce the disease. The 

 Macrosporium is not an active parasite, and entrance to the host must 

 be secured through tissues weakened by some of the means suggested. 

 The use of Bordeaux mixture for this disease has met with only partial 

 success, proper fertilization and cultivation having increased the yield 

 to a greater extent than spraying. 



' Gard. Chron., 4 (1875), No. 81, p. 68. 



