DISEASES OF PLANTS. 247 



Report on economic mycology, E. S. Salmon (Jour. Southeast. Agr. Col. 

 VTyr, IDO.S, No. 17, pp. 2.'i7-3o6, pis. 17). — This report contains observations on 

 the American gooseberry mildew, blacli scab or wart disease of potatoes, black 

 ecab or spot of apples (E. S. K., 20, p. 950), apple leaf spot (E. S. K.. 10. p. 

 549), cherry leaf curl (E. S. R., 20, p. 248), leaf spot of chrysanthemums (E. S, 

 R., 19, p. 659), Rhizoctonia disease of sea-kale (E. S. R., 20, p. 451), and in- 

 fection experiments with ChnjsopliJyctis cndobiotica. 



In the discussion of the American gooseberry mildew and the black scab or 

 wart disease of potatoes, the author traces the distribution of the fungi, calls 

 attention to their destructiveness, and suggests means for their control. 



In the infection experiments with Chrysophlyctis, the fungus causing the 

 black scab or wart disease of potatoes, it was found that if resting spores are 

 subjected in November to temperatures varying from — 5° to — 6° C. for 1| 

 hours they are able to germinate and infect sprouting potatoes at once. 

 Further experiments showed that exposure for 4 hours to a temperature of 

 — 5" to — 8° did not destroy the germinating power of the resting spores, and 

 this is believed to show that winter plowing of soil infested with the disease is 

 useless as a means of destroying the spores. 



Diseases of the cultivated plants for the years 1906—1908, L. Hauman- 

 Merck and J. A. Devoto (BoI. Min. Agr. [Buenos Aires], 10 (1908), No. 1-2, pp. 

 98-113; aJ)s. in Centhl. Bakt. [etc.], 2. At)t., 25 (1909), No. 19-25, p. 520).— This 

 gives a list of 43 diseases, mainly on field, forage, orchard and truck crops, 

 distributed as follows : Phycomycetes 7 species, Ascomycetes 12, rusts and smuts 

 17, imperfect fungi 5, a bacterial disease {Bacillus olew) of olives, and an alga 

 {Mycoidea parasitica) parasitic on the leaves of the magnolia. 



Six insect pests are noted, of which 4 are aphids, 1 a mite (PJiytophtiis 

 vitis), and a red spider (Tetranychus). 



Notes on plant pathology, J. B. Pollock (Rpt. Mich. Acad. ScL, 11 {1909), 

 pp. Ii8-5Ji). — Notes are given on Ganodcrma sessile, a wound pai'asite on the 

 maple; Polystictus hirsiitus, a wound parasite on mountain ash; the conidial 

 form of Sclerotinia on the wild black cheri'y ; and on the identity of the Euro- 

 pean and American forms of Sclerotinia friictigena. The latter has been noted 

 elsewhere (E. S. R., 23, p. 150). In addition a new species of Sclerotinia, 8- 

 (rstivalis, occurring on old mummied apples, is described, this species differing 

 from other species of the genus in the time at which the apothecia develop. 



Some Alabama plant diseases, F. E. Lloyd, C. S. Ridgway, and II. J. Chat- 

 TEKTON {Bid. Ayr. Dept. [Ala.], No. 32, pp. 22, figs. 8). — Popular descriptions, 

 together with suggestions for prevention, are given of the pecan disease due to 

 Fusicladiiim effusum, fire blight of pears, apples, etc., caused by Bacillus amy- 

 lovorus, and black rot of grapes {Guignardia hidwellii). 



Contribution to the fungus flora of middle Russia, A. Potebnia {Ann. 

 Mycol., 8 {1910), No. 1, pp. 42-93, figs. 38).— This is a list of fungi, mainly 

 parasitic, in which the groups Sphseriales, Sphaeropsidales, and Melancouiales 

 are treated at considerable length. 



Researches on the loose smut of grains, O. Appel and E. Riehm {Mitt. K. 

 Biol. Anst. Land. u. Forstw., 1909, No. 8, pp. 9-13). — This is a summary of re- 

 cent investigations by various writers on the different methods of combating the 

 loose smut of grains. The principal conclusions have been noted elsewhere 

 (E. S. R., 22, p. 48; 23, p. 46). 



A bacterial disease of alfalfa caused by Pseudomonas medicaginis n. sp., 

 W. (i. Sackktt {Science, n. ser., 31 {1910), No. 797, />. 553). — A technical de- 

 scription is given of P. medicaginis n. sp., which is held to be the cause of the 

 bacterial disease of alfalfa. Previous notes have been given regarding this 

 disease (E. S. R., 22, p. 46). 



