546 EXPEEIMENT STATION RECORD. 



applied at the rate of 1 gal. per square foot, is said to destroy the fungus if 

 the soil is covered with coarse sacking for a few days, after which the fumes 

 must be perruittetl to escape before planting the seels. Pea spot (Ascochyta 

 pisi) attacks also wild legumes. It is stated that this fungus may be con- 

 trolled with Bordeaux mixture if applied on Its first appearance. 



Leaf spot and some fruit rots of peanut, F. A. Wolf (Alabama Col. 8ta. 

 Bui. 180 {IDUt), pp. 127-150, pis. 5). — The author descril)es three fungus dis- 

 eases of ])eanuts occurring in Alabama. These are leaf spot, due to Cercospora 

 pernonata. a red rot of th^ peanuts causetl by ticocofimoHpora vasinfecta, and 

 {i sclerotial rot due to Sclerotium rolfsii. 



The most prominent symptom of the leaf spot disease is said to be the 

 presence of chestnut brown areas on the leaves, petioles, and stems, which may 

 result in considerable defoliation, impairing the hay crop and indirectly 

 reducing the yield of peanuts. Crop rotation and seed disinfection are recom- 

 mended as preventive measures, spraying being considered impracticable. On 

 account of the fact that the fungus has been found to hibernate on diseased 

 leaves lying in the field, attention is called to the necessity of their destruction. 



The fungus causing the red rot is not considered parasitic, and it occurs on 

 peanuts only as a saprophyte. Digging the crop when mature without delay. 

 It is thought, would reduce the amount of injury sometimes done. 



The sclerotial rot is due to a parasite, both the shell and the kernel being 

 destroyed. In addition to peanuts the fungus causing this disease is known to 

 occur on a large number of host plants and as a consequence no remedial meas- 

 ures such as rotation can be recommended for its control. 



A bibliography is appended. 



Potato diseases, A. S. Horne (Ann. Appl. Biol., 1 (1914), Xo. 2, pp. 183-203, 

 figs. 8). — This is a brief examination and discussion of several contributions 

 from various authors regarding diseases of potato, including ChryKophliictis 

 cndohioUca, Phytophthora infestans, sprain, Fusariuin solani, curl, Spongospora 

 solani, and other diseases. 



Potato scab, B. F. Lutman and G. C. Cunningham (Vermont Sta. Bui. 184 

 (1914), PP- ^^h pis. 12, figs. 7). — In a previous publication attention was called 

 to the pathology of the potato scab (E. S. R., 30, p. 539). In the present 

 bulletin a detailed account is given of the investigations, from which it is con- 

 cluded that the stimulation of cork products is due to the growth of an organ- 

 ism, resulting in the formation of chemical substances which are absorbed 

 and which cause the cork cells to increase in size and number. According to 

 the authors the organism which has hitherto been referred to as Oospora 

 scabies should be designated as Actinomyces chromogcuus. 



This organism is widely spread, occurring in practically all soils, but is 

 most numerous in those which are rich in humus. The parasitism of the 

 organism is facultative and may be induced by an alkaline condition of the 

 soil, the presence of moisture, and an abundance of organic matter of the soil. 

 It is believed that some strains of the organism may have developed this char- 

 acter to a greater extent than others, but the authors were iniable to recognize 

 any morphological or cultural characters which would distinguish them. The 

 organism is considered to be spread more probably through manure and humus 

 than through scabby potatoes, though the latter should be avoided or thoroughly 

 disinfected. 



A weak acidity of the soil instead of a neutral or slightly alkaline condition 

 id consideretl the most hopeful attack in combating this organism. The use 

 of flowers of sulphur is said to be helpful in diminishing the amount of scab, 

 but may prove harmful to other crops if applied in too large quantities. No 



