New York Agricultural Experiment Station. 377 



(8) It appears that three applications of Bordeaux mixture are 

 not sufficient for potatoes on Long Island. In the early part of 

 the season it is necessary to fight flea-beetles and Colorado beetles, 

 in midsummer the early blight must, be kept in check, and in the 

 latter part of the season late blight and flea-beetles make their 

 appearance. The plants need protection throughout the season. 



(9) One-to-eleven Bordeaux gave slightly better results than 

 l-to-7 Bordeaux. As a repellent of insects the weak mixture 

 seems to be fully as effective as the stronger mixture. Had 

 blighlt been prevalent the results might have been different. The 

 use of the weak mixture cannot be recommended without further 

 trial. 



(10) Plants sprayed five times with Bordeaux mixture at the 

 rate of 100 gallons per acre, yielded in one case 15 bushels per 

 acre and in another case 27 bushels per acre more than plants 

 sprayed at the rate of 50 gallons per acre, 



(11) A trial of the Hudson Special Bordeaux Sprayer showed 



it to be an efficient sprayer for applying Bordeaux mixture to 



potatoes. 



INTRODUCTION. 



It is a well-known fact that the ravages of the late blight or 

 rot blight {PhytopMliora infestans) of the potato can be prevented 

 by spraying the plants with Bordeaux mixture. Many carefully 

 conducted experiments have been made, both in this country and 

 in Europe, and in almost every one of these experiments the late 

 blight and potato rot have been successfully controlled by spray- 

 ing. The amount of evidence is so great that we are obliged to 

 accept it as an established fact that late blight can be prevented 

 by spraying. 



The disease makes its appearance in midsummer during warm, 

 moist weather and rapidly destroys the plants, whole fields some- 

 times being ruined in the space of three or four days. At dig- 

 ging time many of the tubers are found to be rotten. Spraying 

 should be commenced before the disease rnakes it appearance 

 and two or three applications made at intervals of about two 

 weeks. In cases where the disease has been severe this treat- 



