138 Report oF THE BoraNIcAL DEPARTMENT OF THB 
of an Kclipse No. 2 pump mounted in a 100-gallon barrel on a 
two-wheeled cart.22 One man did both the pumping and the 
driving. 
The bordeaux used contained six pounds of blue vitriol to 50 
eallons of water with sufficient lime added to satisfy the yellow- 
prussiate-of-potash test. Paris green was used freely with the 
bordeaux—at the rate of two pounds to 50 gallons in the first 
four sprayings. Altogether 110 pounds of paris green were used 
on the 14 acres which is at the rate of nearly eight pounds per 
acre. This is a considerably larger quantity per acre than was 
used in any of the other experiments except the Madrid experi- 
ment. The dates of spraying in the experiment lot were June 
20, July 1, 8, 18, 25, 29, August 3 and 12. 
The unsprayed rows were treated three times with paris green. 
Once, when the paris green was applied with a powder gun some 
of the plants received too much and the foliage was slightly 
injured. 
In this experiment the chief enemy fought was late blight, 
Phytophthora infestans, which first appeared on the unsprayed 
rows about July 22 and soon after became so virulent that the 
unsprayed rows were entirely dead by August 10. On this date 
the sprayed portions of the field, although much superior to the 
unsprayed, were nevertheless, badly blighted. All unsprayed 
fields around Southampton were now dead with blight; but the 
sprayed fields, of which there were a good many, were still 
mostly green. 
Flea-beetles, too, were considerable of a factor in the experi- 
ment and it was plain that spraying materially reduced their 
rayages although it did not wholly prevent them. There was 
also some early blight, Alternaria solani, which was more abund- 
ant on the unsprayed than on the sprayed rows. 
The test rows were dug with a potato digger on September 6. 
The yield were as follows: 
Second sprayed row on the west,**® 675 lbs. of marketable tubers. 
Middle unsprayed row, 474 Ibs. of marketable tubers. 
Yield per acre, sprayed, 295 bu. 25 tbs. marketable tubers. 
Yield per acre, unsprayed, 207 bu. 27 lbs. marketable tubers. 
Gain per acre, 87 bu. 58 lbs. marketable tubers. 
2 Hor an illustration of Mr. Jagger’s spraying outfit see Plate V, Bulletin 
241. : 
“Owing to a misunderstanding, Mr. Jagger had already dug the seeond ~ 
sprayed row on the east so that our usual method of taking the yield of the 
second sprayed row on either side could not be followed in this experiment. 
