NOTES AND ABSTRACTS. 



343 



Potato Weevils, New, from Andean South America. By W. D. 



Pierce {Jour. Agr. Research, i. p. 347-352, Jan. 1914 ; figs.). — 

 Weevils have been found in potatos showing no external signs of their 

 presence, and as a result the Federal Horticultural Board of the United 

 States has excluded South American potatos from the United States. 

 In 1913 the weevil Rhigopsidius tucumanus Heller was found in potatos 

 from Peru, Bolivia, and Chile, and the author now describes and figures 

 two other new species which similarly burrow in the flesh of the potato. 

 They are each representatives of a new genus, viz. Premnotrypes 

 solani and Trypopremnon latithorax. The work of the three weevils is 

 very similar, but the first is more common than the other two. 



F. J. C. 



Potatos, Black Heart of. By E. I. Bartholomew {Phytopatho- 

 logy, iii. p. 180, June 1913 ; figs.). — Tubers affected by this disease 

 show a blackening of the tissues, especially in the central regions. The 

 appearance apparently developed during somewhat peculiar conditions 

 of transit, and the author found it not difficult to reproduce the blacken- 

 ing by exposing tubers in a drying oven for from eighteen to forty- 

 eight hours to a temperature of 38° to 45° C. Chilhng did not produce 

 it, nor was it evident that excess of either oxygen or carbon dioxide 

 influenced the changes. The change is not evident from outside, and if 

 the tubers be allowed to remain for some time the blackened tissues 

 of the centre shrink, leaving a hollow with a black lining. The 

 appearance is entirely different from that associated with sprain. 



F. J. C. 



Potatos, Late Blight and Rot of. By M. F. Barrus {U.S.A. Exp. 

 Sin., Cornell, Circ. 19 ; 1913). — ^The symptoms of Phytophthora in- 

 festans attack are described, and spraying with Bordeaux mixture 

 5-5-50 recommended. Lime-sulphur spray causes marked dwarfing 

 in potato plants, and should not be used. — D. M. C, 



PotatoSj Osmotic Pressure in. By M. A. Brannon {Bat, Gaz. 

 Nov. 1913, pp. 433-438 ; four figs.). — The osmotic pressure of sap 

 from potatos kept in an ice-box continually increased from October 11 

 to January 23, and reached fourteen atmospheres on July 17. In 

 those kept at ordinary temperatures the pressure decreased until 

 April 7. Unfiltered sap showed higher pressure than filtered, and in 

 larger potatos of the same variety it was greater than in small ones. 

 The ice-box potatos showed more pronounced acidity. This acidity 

 is most marked near the " eye " and disappears in the cortex as the 

 distance from the " eye " increases. The author concludes that starch 

 and hemicellulose are hydrolysed by enzymes which are released 

 through the acidity. They furnish the necessary energy for metabolism 

 during cold storage. — G. F. S. E. 



Potatos, Wart Disease of {Journ. Bd. Agr. vol. xxi. No. 2, 



pp. 135-136). — ^The note referred to is a communication which the 



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