New York Agricultural Experiment Station. 137 



unsprayed fields in the neighborhood were dead and brown. During 

 the following week the contrast between the sprayed and unsprayed 

 rows become more and more conspicuous until about September 19 

 at which time the unsprayed rows were dead throughout one-half 

 their length and had only one-fourth to one-third their foliage over 

 the other half. On the same date the adjacent sprayed rows were 

 still quite green except toward the south end where they had lost 

 about one-third their foliage. 



On September 28 the north half of the field was in almost full 

 foliage and even as late as October 9 some of the plants here were 

 still quite green. This field continued green fully three weeks longer 

 than unsprayed fields in the same neighborhood. 



Nevertheless, over the south half the plants were considerably in- 

 jured by blight, and there was also considerable loss from rot all 

 over the field, being worst on the unsprayed rows. 



There was no damage done by early blight, and flea-beetles caused 

 no damage of any importance. " Bugs " were thoroughly controlled 

 both on the sprayed and unsprayed rows by the one application of 

 poison. The soil was a sandy loam. The potatoes were of two 

 varieties, mixed — Carman No. 3 and Rural New Yorker No. 2. 

 They were planted June 8 to 10. 



The method by which the increase in yield was determined can be 

 best explained by the use of a diagram as follows : 



