INSECTS OF THE CHERRY 261 



disease is very unsightly. It consists of wart-like bodies 

 which cover a considerable area on the twigs and the limbs. 

 It is confined entirely to the woody parts and is usually 

 found on one side of the branch. As the infected part 

 increases in size the bark is broken and the fungus is seen. 

 These knots will have reached full size by early summer. 

 Since the knots are points of infection, and the fungus is local 

 in its habit, it is evident that by the pruning out of the knots 

 the disease can be eradicated. In fact only a few knots are 

 present when the infection begins, and by carefully watching 

 the tree and cutting off and destroying the knots as soon 

 as they appear, little trouble will be experienced with this 

 disease. 



Shot-hole Disease. — The name of this disease is significant, 

 referring to the appearance of the leaf, which resembles one 

 that has been shot full of holes with a shotgun. This disease 

 occurs on the cherry and the plum and occasionally on the 

 other stone fruits. Small infected areas appear on the leaves 

 and as the disease advances these diseased spots gradually 

 die, shrink in size and fall out, leaving a small hole in the leaf. 

 A number of these diseased areas occasionally coalesce and 

 make a larger hole. This disease can be held in check by 

 destroying all leaves, which is best done by cultivating the 

 soil and turning the leaves under. If the trees are sprayed 

 with the standard 4^-50 Bordeaux mixture early in the spring 

 while they are dormant it will aid considerably. Successive 

 sprays should follow, with a dilute alkaline Bordeaux mixture, 

 although on some plants the use of Bordeaux may be accom- 

 panied by some injury to the foliage. 



INSECTS OF THE CHERRY. 



Plant Louse. — The plant louse often becomes troublesome, 

 and especially on the sweet cherries, which are more liable 

 to injury by the louse than the sour varieties. The damage 

 to this plant by the plant lice is similar to that of any other 

 plant. These insects are always more abundant on the under 

 side of the leaves, and this irritation causes them to curl 



