178 On the Diseases of Fruit Trees. 



spring, after heading them down low, planted them to a new 

 wall, apart from any others ; they have since thriven well, 

 and out of the entire (about fifty) the disorder made its ap- 

 pearance on one or two only, though all seemed infected in 

 an equal degree in the preceding year. 



The following is also an additional proof, that the disorder 

 is communicated by the dispersion of the seed, and that 

 Peach trees with glandular leaves are not equally liable to 

 the contagion as others. Having planted this year a collec- 

 tion of Peach trees, which I had obtained from France, 

 (about thirty sorts) in one of my houses, they grew remark- 

 ably well until the latter end of the season, when, having 

 occasion to open an end sash, near which, on the wall with- 

 out, a mildewed Peach tree stood, after some time the dis- 

 ease made its appearance on one or two glandless trees, the 

 only ones, of that description, in the house, at the same time 

 the remaining sorts continued perfectly free from attack. 



Such are the appearances which the Mildew presents in 

 those countries, but in warmer climates and higher tempera- 

 tures, it assumes more virulence, and in a greater or less de- 

 gree affects all varieties of the Peach, with few exceptions. A 

 warm dry state of the air appears essential to its growth and 

 extension, which, on the contrary, is checked and repressed 

 by a cool moist atmosphere. 



Dangerous and destructive as this disorder is, to the Peach 

 tree, yet it is satisfactory to know, that it may be rendered in- 

 noxious, and removed by the timely application of sulphur, the 

 only remedy, which I am acquainted with, that can be termed 

 a specific for the complaint. Soot and lime I have tried with 

 very little effect, but sulphur being so easily procured, and 



