358 SUCCESSFUL FRUIT CULTURE 



weakens the tree, as severe weather in winter following 

 a season of coarse and immature growth, overbearing, 

 injury from insects, etc., etc. 



Remedy — The disease being of so obscure a nature 

 it is not profitable to spend much effort in trying to 

 doctor sick trees, especially as young trees can be grown 

 to bearing size in three years' time, and when trees 

 show unmistakable signs of the disease it is best to pull 

 them out and burn them at any time during the summer, 

 fall or v/inter, and plant young trees in their place. 

 This is the practice in the large peach growing sections 

 of Michigan and other States. Anything that can be 

 done to increase the hardiness and firmness of the wood 

 and bud growth will tend to protect them from this 

 disease, as frequent cultivation, or the application of 

 an abundance of potash and phosphoric acid, with only 

 nitrogen enough to produce a moderate amount of 

 wood, etc. 



Peach Rosette is a disease somewhat of the same 

 nature of the yellows, but appears earlier in the season 

 and is characterized by a more leafy growth, and should 

 be treated the same as the vellows. 



Powdery Mildew (Podosphaera oxyacanthae) — See 

 under the apple. 



Leaf Rust {Puccinia pruni-spinosa) — See under 

 the plum. 



FUNGOUS PESTS ATTACKING THE PLUM 



BlacTc Knot, Blach ^yart, etc. (Plowrightia mor- 

 hosa) — More of the plum trees of both the European 

 and Japanese varieties are destroyed by this pest than 

 by any other causes. It is known by the large black 

 excrescences seen on neglected plum trees, and is a 

 fungous growth, the spores of which enter the tissues 

 at some soft place, and, growing rapidly, soon cause the 

 death of the tree unless checked in its early development. 



