268 THE PEACH. 



powers of nature may, for once, twice, or even thrice, restore a 

 growth of leaves, the shock must at length impair the vitality, and 

 induce an unhealthy condition." This curl of the leaf is produced 

 by the punctures of a small plant-louse, the " Aphis persica" fully 

 described by Dr. Harris in his work on Insects. 



A mixture of tobacco water and strong soapsuds applied with a 

 syringe, early, or as soon as the leaves are one third grown, will be 

 found a good remedy. Barry regards the curl of the leaf induced 

 by sudden change of weather a number of warm days that cause 

 the expansion of the young leaves, followed by a cold, rainy day ; 

 the more severe and protracted the cold, the more severe and fatal 

 the curl. 



The Yellows. What is regarded as the Yellows is little known 

 throughout the West ; neither have we ever observed it, to any ex- 

 tent, in the New England States, except where trees were procured 

 from, or grown on poor, sandy soils, enfeebled and imperfect from 

 their first start. That it may be perpetuated by innoculation, or 

 sowing seeds from trees diseased, we have no doubt ; it therefore 

 behooves every tree grower to be careful from whence he procures 

 his pits for stocks. Prof. Kirtland says : " It is questionable whether 

 any distinct disease occurs, to which this name is applicable. Per- 

 haps it is only a collection of symptoms arising from causes acting 

 either individually or collectively. Facts seem to favor this view, 

 though the insight of popular opinion is in favor of its being a spe- 

 cific and contagious disease." Depredations of the ^Egeria exitiosa, 

 Aphis persica, exhaustion of elements in the soil, and want of correct 

 pruning appear to be the primary causes, and, in reference thereto, 

 Prof. Kirtland further remarks : " In estimating the power and ex- 

 tent of these causes, it should be recollected that an injurious im- 

 pression, acting constantly upon successive generations of either 

 animal or vegetable species, may ultimately establish a hereditary 

 entailment that may be propagated in the form of predisposition 

 to disease, or disease itself. The converse is equally true in pro- 

 ducing health or physical development. 



These several causes have been exerting their influence on the 

 Peach tree for a long term of years, impairing the stamina and 

 health of its fruit germs. These impressions have been propagated 

 and re-propagated, in conjunction with the action of the primary 

 causes of impairment, till at length we have only a sickly progeny." 



The remedy is to cut down and destroy all diseased trees ; the 

 preventive is judicious cultivation. 



Mildew. This is the name applied to a minute fungus which at- 

 tacks the ends of the young branches of some particular varieties, 

 termed serrated or glandless. It checks growth, and renders the 



