250 FUNDAMENTALS OF AGRICULTURE. 



Potato Blights. Under this term are included sev- 

 eral different leaf troubles. Two of these are early 

 blight and late blight. Besides these, there may be 

 the shot-hole injury to leaves caused by flea-beetles. 

 Spraying will protect from the blight fungi, if begun 

 in time and thoroughly done. For early blight, it 

 should begin when the plants are six or eight inches 

 high, two applications of Bordeaux being given two 

 weeks apart; these should be followed by three or four 

 applications of Bordeaux at like intervals. A fourth 

 trouble, more properly termed leaf-burn, is the drying 

 out of leaflets from the tips and margins caused by lack 

 of water. Deep plowing, addition of humus, and fre- 

 quent shallow cultivation will tend to correct the con- 

 ditions that induce this trouble. 



Peach Leaf Curl. Affected leaves are swollen and 

 puckered in an irregular and characteristic way; their 

 color becomes yellowish-green or dull red. They fall 

 early in the season, and when a tree is severely attacked 

 it may be practically defoliated by mid-season. Trees 

 affected with leaf curl do not properly mature fruit 

 during the current season; or make vigorous wood 

 growth; or develop a full number of good fruit buds 

 for the next season. The fungus causing this disease in- 

 fects the young leaves when the buds break. It can be 

 readily controlled by a single application of a good fun- 

 gicide made in early spring just before the buds begin 

 to swell. Either Bordeaux mixture or the lime-sulphur 

 wash used commonly for scale insects is satisfactory. 



Brown Rot. This is the common rot which affects 

 peaches, plums and cherries at the time of ripening, 

 and most seriously in warm, wet weather. It is caused 

 by a fungus, the threads of which grow rapidly inside 

 the tissues of the fruit, and produce here and there 

 over the surface small ash-colored tufts of spore bear- 

 ing branches. The rotted fruit often remains hanging 

 on the trees as dry shriveled mummies during the win- 

 ter. The fungus threads in the dry flesh remain alive, 

 and during the following spring may renew their 

 growth and produce spores that infect the new crop. 



