108 STATE BOARD OF AGRICULTURE. 



swell. Au application of Bordeaux inixtiire should be made when the 

 blossom buds are ready to open, and it should be repeated when the 

 fruit is of the size of a pea. In case the diseases have bt^n troublesome 

 in previous years, and especially if the weather during July and August 

 is wet and muggy, this can be continued with good results every ten 

 days up to w^ithin three weeks of the ripening of the crop. For the 

 first application it will be well to use four pounds of copper sulphate 

 and five pounds of lime in fifty gallons of water, but this can soon be 

 reduced to three and four pounds respectively, and for the last s[»raying. 

 if made after the middle of August, use only two pounds of copper sul- 

 phate and the same of lime in fifty gallons of water. In cases where the 

 rot is very troublesome late in the season, it is often advisable to use soda 

 Bordeaux, which will not spot the fruit. 



rOTATO BLIGHT. 



During the summer of 1905 the conditions were quite favorable for the 

 development of the blight and rot of the potato, and serious loss re- 

 sulted. It had been conclusively shown by experiments carried on 

 at this and other stations that this disease also could be held in check 

 by thorough spraying with Bordeaux mixture, and in lOOG, although 

 the disease was less prevalent than in the previous year, it was prac- 

 ticed with good results in many sections. 



The rot and blight are caused by a fungus which develops rapidly un- 

 der the same conditions as are favorable to the rot of the grape. It 

 seldom does much harm to potatoes that ripen before August first, but 

 the later varities, particularly if on low and wet land, are sometimes 

 entirely destroyed if the weather in August is muggy. Bordeaux mix- 

 ture is also a specific for the early blight whicjj comes in June and 

 July, and if it becomes necessary to spray for the potato beetle, the ad- 

 dition of Paris green will be helpful. For the late or true blight the 

 spraying need not begin until the latter part of July or early August. 

 One application can always be made to advantage, and this should be 

 followed at intervals of ten days with two or three others, if the weather 

 is favorable to the development of the blight. In seasons when un- 

 sprayed vines are entirely destroyed, it is possible to carry a crop through 

 with little or no loss if the vines arc kept covered with the spray. As 

 it is only valuable as a preventive, it is desirable that one application 

 be made before the season comes for the appearance of the disease, but 

 if the weather during August is dry, the periods between the sprayings 

 can be extended, but whenever blight appears, or the Aveather becomes 

 favorable for the development of blight, the vines should receive an 

 application. 



That spraying for blight is a safe investment, even as an insurance, it 

 should be noted that it only costs about one dollar to spray an acre 

 of potatoes, and that as the crop is often entirely destroyed when attack- 

 ed hy blight, four or five ai)plications will result in saving several times 

 their cost. 



