446 EXPERIMENT STATION RECORD. 



connection with this progressive deterioration of clover, the fundamental cause 

 of the trouble has not yet been determined. 



A bacterial disease of cultivated mushrooms, A. G. Tolaas (Phytopathology, 

 5 (1915). No. 1, pp. 51-5Jf, pi. 1). — An account is given of a disease of mush- 

 rooms observed in caves in and about St. Paul, Minn. 



An examination of discolored portions of the mushrooms showed the presence 

 of bacteria, which were isolated, the causal organism being a facultative anae- 

 robe of the Pseudomonas type, corresponding to Bacterium fluorescens except for 

 the fact that in dextrose broth the reaction is acid instead of alkaline. Some 

 experiments were conducted for the control of the disease, spraying with a 

 number of solutions and fumigating with sulphur being tested. 



The fumigation of the mushroom beds with sulphur before planting the 

 spawn gave absolutely clean mushrooms. This treatment, it is said, costs about 

 5 cts. per 1,000 cu. ft. and has proved entirely practical. 



A common but very serious potato disease in Cuba, R. A. Jehle (Modern 

 Cuba, 3 (1915), No. 4, pp. 46-48). — A description is given of the late blight or 

 downy mildew, caused by Phytophthora infestans, with suggestions for its con- 

 trol. 



Experiments in preventing wart disease of potatoes (Jour. Bd. Agr. 

 [London'], 21 (1915), No. 12, pp. 1126-1128).— In a previous publication (E. S. 

 E,., 31, p. 842) the use of formaldehyde for the control of the wart disease of 

 potatoes (Chrysophlyctis endoUotica) was recommended. During the summer 

 of 1914 experiments were carried on in a number of places in England to test 

 the value of this treatment, but with unsatisfactory results. 



Comparisons were made between formaldehyde solution, corrosive sublimate, 

 fertilizing with sulphate of potash, kainit, salt, supeiijhosphate, etc. These 

 experiments were carried out on land that was known to be badly infected 

 with the fungus, but very little difference was observed so far as the amount of 

 disease was concerned. The plats treated with corrosive sublimate seemed to 

 have had an increased amount of disease. 



Experiments on the virulence of Bacillus solanacearum against different 

 Nicotiana species and varieties, J. A. Honing (Bid. Deli Proefstat. Medan, 

 No. 2 (1914), pp. 15). — In continuance of previous work (E. S. R., 28, p. 446) 

 the author studied the alleged immunity of N. rustica, claimed by Uyeda (E. S. 

 B., 18, p. 151) to be resistant to bacterial wilt. 



Of 200 plants (10 each of 20 types) of N. rustica inoculated with B. sola- 

 nacearum, all but one died (a result, moreover, practically duplicated in 6 other 

 species), showing that in Deli, at least, N. rustica is nonresistant and useless 

 for hybridizing purposes. No variety of N. tahacum proved to be really im- 

 mune, and only 3 varieties (2 from Manila and 1 Japanese variety) were less 

 affected than were most species of Deli tobacco. 



Experiments with plants from seed from widely separated regions showed 

 that the introduction of a larger quantity of bacteria, with their excretion prod- 

 ucts, reduced the inoculation pei'iod greatly and was more fatal, the few plants 

 which resisted (10 out of 278) being inoculated by means of a capillary tube 

 and hence with fewer bacteria. These and other observations raise the question 

 as to whether in a fresh culture all or only a portion of the bacteria are 

 virulent. 



It is thought that in Deli the differences in climate and in cultivation are in 

 favor of a greater virulence of B. solanacearum, also that foreign varieties 

 seem to promise no better hope of producing resistant varieties than does Deli 

 tobacco itself. 



Two new species of fungi in tobacco seed beds, P. A. Saccardo and B. 

 Peyronel (Bol. Tec. Coltiv. Tahacchi [Scafuti], 13 (1914), No. 1, pp. 3-6, pi. 1). — 



