26 



POTATO. 



Early Blight. 



Spray with Bordeaux mixture when the potatoes are five or six 

 inches high, about June 20th, or preferably with Bordeaux and Paris 

 green or arsenate of lead, (Nos. 20 or 21). Repeat application 

 every two weeks. 



Late Blight. 



A continuation of the treatment recommended for early blight 

 answers for this blight. To prevent the rotting of tubers, avoid 

 poorly drained soil. 



Scab. 



To destroy germs on seed potatoes soak one and one-half hours 

 in corrosive sublimate, (No. 7) or two hours in formalin (No. 8.). 

 Dry the potatoes after soaking in formalin or corrosive sublimate. 

 Avoid fertilizers containing stable manure, and as scab develops 

 freely in alkaline soils do not use fertilizers containing free lime. 

 The tendency to produce scabby potatoes may be lessened by the 

 use of such fertilizers as acid phosphate and sulfate of ammonia. 



Cf. Wheeler et al. in R. I. Bulletins Nos. 26, ^^ and 40. 



Potato Beetle. 



Spray with a strong stomach poison (Nos. 9, 10, 11 or 12); repeat 

 as needed. 



Flea Beetle. 



Spray with Bordeaux mixture and Paris green or arsenate of lead. 



For the control of blights and insects on potatoes it is best to use 

 a combined fungicide and insecticide, (either No. 20 or 21) as potato 

 beetles are usually troublesome. Paris green acts more quickly on 

 the potato beetle than arsenate of lead, but the latter is more adhe- 

 sive than Paris green, and many growers are using formula No 21 in 

 preference to No. 20. 



