224 Curl of the Peach- Leaf. 



One such is the genus Spharonema, a little swollen wart filled with minute 

 curved spores, or seeds. Some distorted and discolored leaves which had 

 fallen from my peach-trees a few weeks ago were covered with the Sphcero- 

 nema protubcrans (Berkeley), and the microscope revealed the beaded fibres 

 {inycelium) and the curved spores. 



Now, I have no reason to suppose that the cold and tardy spring, nor 

 the frequent cold rains, had any agency in the matter \ but from what 

 source these skin-humors, pathologically speaking, proceeded, further discov- 

 eries in the nature and origin of vegetable growths, whether by chemical 

 combination or other causes, must ultimately decide. 



At one time, I supposed it might be from sudden check of the rapidity 

 of growing by some cold winds or low temperature of the night ; thus 

 arresting the development of the foliage, which in all plants is most felici- 

 tous when heat and light and moisture are present. 



Having noticed in the peach-houses of a friend the identical condition, 

 some of the leaves of trees trained near the heated flues being quite as much 

 affected as if growing out doors, this supposition had to be relinquished. 



The presence of the aphides merely showed that the morbid growth 

 secreted some saccharine-juices, on which they greedily fed. 



Several sorts of ants always attend aphides, in order to solicit from them 

 drops of honey, which they have the power to extort by some pleasant 

 process : so entomologists assure us. 



Does the Sphczronema injure the peach-tree? I have come to the con- 

 clusion that little injury need arise from its presence. The shedding of 

 these diseased leaves is succeeded by a \-igorous growth of healthy ones ; 

 though, occurring as it does about the time of blossoming, it may injuriously 

 affect the crop : but this is only conjectural. 



I think it advisable to treat trees, thus affected, with wood-ashes piled at 

 the base of the trunk : the alkali, washing slowly out by each showier and 

 rain, soaks into the ground, and feeds the roots, thereby effecting some 

 chemical change in the fluids which permeate the growing tissues, and 

 which may prevent the development of the fungus. 



Whether this disorder has any thing in common with the yellows, I am 

 unable to say, not being familiar with that pest of peach-growing. 



Salem, July .9, .867. ^'^'^ ^- R^^^^^i^- 



