PEACH DISEASES 287 
The prevailing opinion of the modern pathologists is that 
the disease is caused by a parasite which as yet has not been 
seen. It was long ago established that the disease is communi- 
cable, that is, the causal factor may be transferred from a 
diseased tree to a healthy one, and after a time the latter tree 
will show symptoms of yellows which in due time run their 
course. Buds from diseased trees convey the causal factor of 
yellows to the stock on which they are inserted. The inocu- 
lum, whatever its nature, is apparently carried in a few diseased 
cells which, if induced to unite with normal cells of the stock, 
will cause the stock to become diseased. Diseased seeds also 
carry the inoculum; and there are probably other ways in 
which it is carried. 
Control. 
The knowledge of remedial measures is about as meager 
as that of the causal relations. “Cures” are worthless and 
impossible. It has been shown that while fertilizers make the 
trees temporarily greener and apparently more vigorous, yet 
in the end they are of little or no value in the control of yellows. 
Trees have been treated with such materials as lime, wood 
ashes, kainit, muriate of potash, dissolved bone-black, bone-ash, 
nitrate of potash, nitrate of soda, sulfate of ammonia, tobacco 
dust, dried blood and stable-manure. Treated trees are just 
as likely to be attacked as those left untreated. 
The prompt removal and destruction of affected trees has 
been recommended since 1828. The advice is still reliable. 
It has been practiced effectively in the State of Michigan in 
‘ years past. The eradication of diseased trees must be an 
annual operation until no traces of yellows remain. Where 
no such efforts have been made to exterminate the disease, 
it has prevailed to such an extent that orchards have been 
destroyed and the culture of peaches abandoned. In order to 
accomplish general and effective eradication, laws have been 
enacted in many states. The first was enacted by the legis- 
