180 On the Diseases of Fruit Trees. 



attacked are crisp, and assume a swollen, crumpled and suc- 

 culent appearance ; the shoots themselves are affected by it 

 in the same manner, and never produce either good blossom 

 or healthy wood. It is probably occasioned by the sudden 

 contraction or destruction of the vessels, and extravasation of 

 the sap, when cold chilly winds and frosts immediately suc- 

 ceed warm sunshine, and soft genial weather ; in such case, 

 the diseased shoots should be rubbed off where they can be 

 spared ; where not, the tops should be pinched down to 

 that healthy part, which is generally at their lower end ; and 

 from the remaining eyes, fresh shoots will push in sufficient 

 time to ripen perfectly. 



The Curl principally attacks those sorts of the Peach, 

 which have leaves deeply serrated and devoid of glands, and 

 it probably proceeds in part from the same causes which oc- 

 casion the blister, aided by the operation of drying winds. 

 The leaves and tops of the shoots affected curl up and emit 

 a saccharine secretion, which attracts the Aphides, these, by 

 extracting the juices of the leaves and shoots, destroy them, 

 and the tree consequently perishes. 



Mulching round the stem of the tree, and keeping its head 

 and the mulch moist by watering, will act as a preventive, 

 or restore it to its health. The insects should be destroyed 

 by fumigation with tobacco, or by washing the tops of the 

 shoots with tobacco water, or by sprinkling them with snuff 

 after watering. 



Gum. This complaint is of frequent occurrence, and pro- 

 ceeds from a variety of causes ; and it is a more formidable 

 enemy than either Mildew or Blight ; being in most cases in- 

 curable. It may be distinguished in the early stages of its 



