New Yorn AGRICULTURAL EXPERIMENT STATION. EVD 
ing of the margins and tips, and foliage lighter green than 
normal.” | 
On both sprayed and unsprayed rows fully two-thirds of the 
plants were more or less aifected, some of them badly. Spraying 
seemed to check this disease only slightly. 
The test rows were dug with a potato digger on October 15. 
The middle unsprayed row and the second sprayed row on either 
side were weighed separately with results as follows: 
Second sprayed row on the west, 364 pounds marketable tubers. 
Second sprayed row on the east, 397 pounds marketable tubers. 
Average of two sprayed rows 38014 pounds marketable tubers. 
Middle unsprayed row, 316 pounds marketable tubers. 
Yield, sprayed, 166 bu. 9 lbs. marketable tubers per acre. 
Yield, unsprayed, 137 bu. 59 lbs. marketable tubers per acre. 
Gain, 28 bu. 10 lbs. marketable tubers per acre. 
The yield of culls was as follows: 
Second sprayed row on the west, 27 pounds. 
Second sprayed row on the east, 27 pounds. 
Average of two sprayed rows, 27 pounds. 
Middle unsprayed row, 19 pounds. 
Difference in favor of sprayed rows, 314 bushels per acre. 
The west field.—In this field there were three varieties—Gold 
Coin, Carman No. 3 and Rural New Yorker No. 2. In the last 
named variety three rows were left unsprayed. These rows were 
920 feet long, three feet apart and 15.78 rows were required to 
*8\WWe have observed this disease before, most frequently on Long Island. 
In 1903 there was a little of it in the ten-year experiment at Geneva (see 
Bul. 241, top of page 260). In the Spencerport experiment no effort was 
made to determine the cause. In former years we have made a careful 
examination of the underground parts without being able to locate the 
trouble. Usually, there are no lesions on the subterranean stem and the 
seed piece is quite as likely to be sound as otherwise. The roots are scant... 
It is neither tipburn nor sunscald as these diseases are generally understood. 
Neither is it the stem blight described in our Bulletin 101, page 83. The 
symptoms above ground are different and there is no discoloration of the 
fibro vascular bundles at the stem end of the tubers as in the case of stem 
blight. In some ways it resembles the rosette disease described by Selby 
(Ohio Exp. Sta. Buls. 139 and 145), but Rhizoctonia is not associated with 
it. Undoubtedly, the cause of the trouble is to be sought below ground. In 
the Spencerport experiment the “seed” appears to have been weak. Many 
of the “ seed” pieces failed to grow, the result being a thin stand of plants. 
