Peach 
In the Fast bacterial spot is probably the most serious disease 
with which the peach grower. has to contend. No really satisfac- 
tory control measure is known, and the continued defoliation year 
after year weakens the trees and predisposes them to winter injury. 
Brown rot, scab, and peach leaf curl are three fungus diseases 
widely distributed in the United States. In certain seasons they 
can cause extensive crop losses, particularly in the humid East, 
and sometimes even western orchards suffer from brown rot and leaf 
curl. Control measures that are effective in a1] but extremely 
rainy seasons have been developed and are widely used by commercial 
growers. 
Coryneum blight is a destructive disease confined to western fruit 
orchards. It causes shot-hole of the leaves and twig blighting and 
spotting of the fruit. Like the leaf curl fungus, the organism is 
a constant threat, and growers regularly apoly a dormant spray which 
gives effective control. 
Phony disease was first ohserved in central Georgia in 1890. It 
oceurs in the Southeastern United States and in scattered areas as 
far west as Oklahoma and north to Illinois and Pennsylvania, The 
affected trees develop shortened internodes, numerous lateral 
branches, and flattened dark-green Jeavas. The fruit becomes pro— 
gressively smaller and inferior in quality. In addition to peach 
the disease attacks nectarine, apricot, almond, and wild and culti- 
vated plum. The virus that cuases it is spread by insects. Affect- 
ed trees are not killed, but their productive capacity and conse- 
quentiv their commercial usefulness is impaired by the second vear 
after infection can be diagnosed. 
Phony peach is particularly destructive in Georgia, where it is 
not uncommon for an orchard to be 99 percent infected by the time 
it is 12 vears old. The only control measure known is removal of 
affected trees. and in a definite eradication program begun in 1929 
ahout 1,600,000 trees have been removed and destroyed. Losses 
in 1952, based on trees removed from 19l)9 to 1951 on account of 
the disease, were estimated to be in excese of $1.5 million. These 
losses include, besides direct loss of crop, losses to the trans- 
portation, container, and insecticide industries and losses affecting 
sales of nursery stock. Should the disease be introduced into 
California, it would threaten an $80 million industry. Insect 
species closely related to the vectors of phony disease are know 
to occur in California. 
Peach mosaic, another virus disease of peach and certain horticul- 
tural varieties of plum, is general in the Rio Grande Valley, 
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