372 Fruit-growing in Arid Regions 



The treatment consists in spraying with white hellebore or 

 with arsenate of lead. Most of the insects may also be killed by 

 simply dusting the trees thoroughly with air-slaked lime, wood 

 ashes, or with road dust. 



San Jose Scale. See under Plum. 



DISEASES AND INSECTS OF THE PEACH 



Fungous Diseases 



Crown-gall. See under Apple. 



Mildew (Podosphcera oxyacanthce .) This is the only disease 

 for which our orchardists have found it necessary to spray, and 

 that in only Comparatively few instances. This is a surface- 

 growing fungus, and in its early stages appears as white frost-like 

 patches on leaves, twigs, or fruit. The leaves on new growths are 

 most susceptible to attack and are often much crumpled and 

 dwarfed, and later many of them fall. Thus the twigs are checked 

 in their growth or killed outright, and the leaf surface reduced. 

 It attacks the fruits when they are young, and the flesh under the 

 spots becomes hard and the skin takes on a brown color. The 

 hardening of the flesh arrests development at that point, and 

 consequently the peaches are unmarketable. Entire crops have 

 been ruined in this way. 



Fortunately, mildew is easily controlled by spraying with 

 bordeaux mixture, preferably in early spring before the leaves 

 are out. If spraying is deferred until the leaves have started, 

 only half of the amount of copper sulfate may be used. Bordeaux 

 mixture of full strength is usually fatal to peach foliage. 



Yellows. The true peach-yellows has never been found in 

 this region. In a number of localities, however, peach trees have 

 developed yellow foliage, and some of the trees have died, and 

 thus the suspicion has been aroused in some quarters that this 

 dread disease has at last made its appearance in our orchards. 



The first thing one notices in going into such localities is that 

 not only are the peach trees affected, but that other trees present 

 a similar appearance; even the cottonwood is not exempt. But 

 there is in reality little similarity between this condition and true 



