FUKGOUS DISEASES 357 



cause an early and rapid growth and is followed by very 

 low temperature, the growth of the leaves is so checked 

 that this fungus finds the right conditions in which to 

 develop; the leaves become thickened and distorted and 

 after a time drop off, to be followed by another set of 

 leaves a little later. If the trees are vigorous and 

 healthy the growth will be but little checked by this 

 attack, but if the trees are not vigorous the injury is 

 often very great. It is not often seriously injurious in 

 orchards in rather light land and on high elevations. 

 In the orchards of the Massachusetts agricultural college, 

 which the author has had charge of for thirty years, 

 no serious injury has occurred, but two seasons, and 

 none to speak of for fifteen years, or since the practice 

 of spraying has been a part of the routine of the care 

 of the orchards. 



Remedy — Spraying before the leaves unfold with 

 the standard bordeaux, and again soon after they are 

 well developed with dilute bordeaux (4:4:200), is a 

 certain remedy. 



Peach Yellows — This is an obscure disease, or 

 condition of growth, of which no specific fungus or 

 bacterial germs or growth has been discovered. It 

 shows itself in many different ways. When it attacks 

 the tree it may be known by a smaller growth of leaf, 

 narrow, of a lighter color in its first stages, and as it 

 advances they grow in clusters or tufts and are often 

 of a reddish color; sometimes only one branch is 

 affected, but sooner or later the whole tree will die 

 unless it be severely headed back and fertilized abund- 

 antly. The fruit ripens prematurely, is of a more 

 brilliant color than is usual, and often bitter to the 

 taste. It is also of small size. Most old trees as they 

 approach maturity show all of the symptoms of the 

 yellows. The disease is probably of a physiological 

 nature and may be brought on by any cause that 



