southern California, Utah, Arizona, New Mexico, and other parts 
of Texas and Mexico. It has been reported from southern Oklahoma, 
western Arkansas, and western Colorado. The virus is present in 
many forms, some of which are very mild in:their effect and others 
very destructive, particularly on the J. H. Hale, Elberta, and 
Rio Oso Gem varieties. In some areas fruit production is markedly 
reduced both in quality and quantity. 
Control of peach mosaic is difficult owing to its extensive range 
plus the presence of some mild forms that make detection difficult. 
Removal of affected trees coordinated with a nursery-inspection 
program and quarantine procedure is preventing further spread of 
the disease. Where no effort is made to control the disease, in- 
fected orchards become unprofitable within a few years. Thus far 
about 400,000 peach trees have been destroyed by the infection. 
Direct losses during 1952, on the basis of trees removed because 
of the disease between 1950 and 1952, were estimated to be about 
$93,000. The value of the 1952 peach crop in the infected areas 
of States where control programs were conducted was estimated to 
be in excess of $10 million, not including the nursery products 
regulated under State quarantines, which were estimated to be 
worth around $700,000. 
Pears 
The destructive effect of pear blight has restricted the commer- 
cial production of high-quality pears almost exclusively to the 
Pacific Coast States. Under the more arid climate in these States 
pear growing can be profitable even though none of the orchards 
are entirely free from the threat of pear blight. 
However, pear scab and stony pit are important problems facing 
commercial growers in the Far West. Pear scab is present every 
year and causes spots on the leaf, fruit, and twigs. The fruit 
is distorted and rendered unmerchantable, and sometimes the trees 
are partially defoliated. Organic fungicides will control the 
organism, but they must be applied at proper intervals. Stony pit, 
a virus disease, causes hard pits to form on the fruit. Badly 
distorted fruit is worthless. Severity of the disease fluctuates 
from year to year. No control measure is known, but fortunately 
the Bartlett pear, although a symptomless carrier, shows no bad 
effects from infection. 
Pecans 
The commercial pecan industry is located in the Southern States 
from South Carolina through Georgia, Florida, and westward to 
Texas and Oklahoma. Scab is present throughout this region and 
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