msmse§ of PLAi^fg. 449 



a result of cultural experiments what are probably the resting spores liave been 

 found, as noted elsevvliere (E. S. R., 22, p. 346). 



A method of testing disease resistance of the tubers has been devised, in which 

 sterile living plugs cut from the tuber are inoculated with the fungus and the 

 amount of growth comparetl after 9 to 12 days. In this way it has been found 

 possible to estimate quite accurately the degree of resistance or susceptibility to 

 disease. 



Outbreak of potato canker in Newfoundland, and the danger of its intro- 

 duction into the United States, H. T. Gussow {Abs. in Science, n. set:, 31 

 (1910), No. 803, p. 796). — The presence of potato canker {ChrysophhjcUs endo- 

 biotica) in Newfoundland is reported, and the possibility of its introduction into 

 the United States and Canada is pointed out. A description of the disease and 

 Its causal fungus has been given elsewhere (E. S. R., 22, p. 545). 



Wart disease of potatoes checked by greening {Jour. Bd. Agr. [London], 17 

 (1910), No. 1, pp. JfS, 7/7). — In a brief note it is stated that the greening of 

 potatoes checks to some extent the development of the wart disease due to 

 Synchi/trium (Chrysophlyctis) cndobioticum. The infection seems to be only 

 through the eye of the potato, and where sprouts had been produced through 

 the process of greening a high degree of Immunity was obtained. 



Potato wilt and dry rot (Fusarium oxysporum), W. A. Orton (Abs. in 

 Science, n. set:, 31 (1910), No. 802, p. 751). — A note is given on this disease, 

 which has been previously described (E. S. R., 15, p. lOSS). The author states 

 that it is becoming one of the most widespread and destructive diseases of 

 potatoes, appearing to occur throughout the United States, but most serious in 

 the irrigated sections of the West and in the southern half of the potato belt. 



Three types of injury occur. The most serious and least recognized is a 

 wilting and premature ripening of the plant due to infection of the stem and 

 underground portions. The second form is a dry rot beginning at the stem, 

 which develops most rapidly in warm temperatures, and third, the fungus is 

 responsible for a considerable portion of the poor germination in the spring. 



Of methods for control the selection of seed tubers seems to be the most 

 promising. A thin slice cut across the stem end of the potato forms a simple 

 test, the vascular ring being brown where the fungus is present. While there 

 are indications that resistance can be bred, the author states that no existing 

 varieties are known to be very promising in this regard. 



Sulphur injury to potato tubers, W. A. Orton and Ethel C. Field (Abs. in 

 Science, n. ser., 31 (1910), No. 803, p. 796). — During the progress of experiments 

 in California in 1909 for the control of the potato scab, it was found that when 

 the crop was dug many tubers from the sulphured rows showed sunken, dark 

 spots from 5 to 30 mm. in diameter, which were relatively free from fungus or 

 bacterial infection. These spots occurred only in tubers from sulphured rows 

 and were more numerous in the heavily sulphured plats, but were present even 

 where the seed pieces had been merely dipped in sulphur. Experiments in the 

 laboratory with potatoes exposed to sulphur fumes resulted in the development 

 of similar spots. 



This injury has apparently not been observed in sulphur experiments con- 

 ducted in the East, and it is thought that it may be due to the fact that the 

 California soils were peaty and became quite dry near the siu'face so that 

 volatilization of the sulphur was effected. 



Potato spraying experiments in 1909, F. C. Stewart et av. (New York State 

 Sta. Bui. 323, pp. 17-52). — The results are given of 2G separate exi)erinients, 

 these constituting the eighth year of work in a ten-year series of potato spray- 

 ing experiments with Bordeaux mixture, together with a summary of results 

 obtained each year to 1909, inclusive. 



