POTATO BLIGHT. 



The potato crop is liable to serious losses from two sources, 

 which losses are to a great extent preventable. These two 

 sources of loss are the Colorado beetle, or potato bug, and the 

 blight or rust. Every farmer knows how to deal with the potato 

 bug. Paris green is the sovereign remedy, but it is only within 

 a comparatively few years that a successful treatment has been 

 found for the blight. It seems now, however, that an effective 

 remedy has been found in the Bordeaux mixture. 



The blight is caused by the growth in the potato vines of 

 minute parasitic plants, known as fungi. There are two dis- 

 tinct species of fungi which produce the blight in potatoes, — one, 

 known botanically as Macrosporiian sohuii, causes what is now 

 known as the early blight, the other, Phytophthora infestans, 

 causes the late blight which has been the most common and 

 destructive. Blight, rust, and rot are the various names by 

 which it has been called. This disease seems to have been 

 especially prevalent during the last few years, doubtless owing 

 to the peculiar conditions presented by the weather, a warm and 

 moist season being most favorable to its development. 



It usually makes its first appearance during the month of 

 August when the vines of the later varieties are in full growth. 

 Early varieties often escape its attacks altogether. The leaves 

 are the first to show its effects. They become more or less dis- 

 colored, then begin at the edge to turn brown and curl up, or, if 

 the weather be very damp, to rot. If a leaf which is only partly 

 dead is closely examined there will be seen on the under surface, 

 especially along either side of the line separating the dead por- 

 tion from the living, a very fine white fuzz ; this consists of 

 the spore stalks of the fungus which is growing within the 

 tissues of the leaf and which constitutes the sole cause of the 

 disease. If a portion of the leaf thus affected be placed under 



