New York Agricultural Experiment Station. 511 



" Pimply " Potatoes. 



A peculiar trouble of potatoes has been brought to my atteu- 

 tion by farmers in the eastern part of Long Island. The affected 

 tubers are known as " pimply '' potatoes. Several varieties have 

 been affected but the Green Mountain has been more commonly 

 affected than any other variety. A farmer near Cutchogue, who 

 raised 180 bushels of "pimply"' potatoes of this variety, was 

 obliged to sell them at five cents per bushel below the market 

 price because of their condition. Outwardly, the tubers are per- 

 fect, except for the so-called " pimples," which are low convex 

 elevations, usually scurfy at the summit, from 3 to 5 millimeters 

 in diameter, and distributed irregularly over the surface. Ninety- 

 three such pimples w ere counted on a single medium-sized tuber. 

 Upon removing a thin jjaring the flesh of the potato aj)pears to be 

 punctured here and there with short, brown, woody slivers, which 

 give it an unsightly appearance when cooked. There is but a 

 single " sliver " underneath each '' pimple." Ten of the " sliv- 

 ers " which were measured, varied in length from 2 to 5 millime- 

 ters, the average length being 2.9 millimeters (^.-inch). Micro- 

 scopic examination shows that the " sliver " consists of a small 

 tube surrounded by cork-cells. The surrounding cells within a 

 radius of from one to two millimeters are markedly deficient in 

 starch, while, curiously enough, the tube itself is filled with loose 

 starch grains. 



As to the cause of the " slivers," the most rational theory is 

 that some insect punctured the skin of the iuber while it was 

 growing and the plant, in its effort to heal the wound, produced 

 cork-cells around the puncture. Almost any slight injury to the 

 skin of a potato tuber will result in the formation of cork-cells. 

 The absence both of insect eggs and of larval castings from the 

 tubers indicates that the punctures were made for feeding pur- 

 poses, rather than for the deposition of eggs. 



A New Fusarium on Potato Stems. 



In July of the past season a farmer in the vicinity of Canan- 

 daigua, N. Y., sent to the Stalion some potaio stalks which were 



