New Yoek Agricultueal Experiment Station. 461 



preventive treatment which can be recommended is digging out 

 and burning the infested plants immediately upon the first ap- 

 pearance of the disease. This treatment will materially check 

 the disease. Affected plants may usually be detected before the 

 rust breaks out on the leaves. The diseased leaves have a pale 

 orange tinge and present a sickly appearance which one soon 

 comes to recognize as characteristic of rust-infested plants. Di- 

 seased canes are also apt to be much freer from prickles than 

 are healthv canes. 



LEAF-SPOT. 



(Septoria rubi Westd.) 



A leaf-spot of raspberries is caused by the same Septoria which 

 attacks blackberries. It is discussed on page 419. 



The disease seems to be less troublesome on raspberries than 

 it is on blackberries. 



ROOT KNOT. 



The roots of raspberries are often covered with galls which 

 are similar to those found on peach roots (see page 43Y) and are 

 probably due to the same cause. Our knowledge of these root 

 galls is imperfect. To both raspberry and the peach they are 

 very injurious. There is some reason for believing that the di- 

 sease may be communicated from the peach to the raspberry and 

 vice versa. Hence it is advisable to avoid planting peaches on 

 soil in which raspberries have knotted badly. N'either should 

 raspberries be planted where peaches have been affected with the 

 root knot. 



EASPBERKY INSECTS. 



CANE MAGGOT. 



(Phorhia sp.) 



Description. — This insect works only in the new shoots causing 

 them to wilt and finally die. This wilting of the shoots is first 

 noticeable in May. The adults first appear in spring toward the 



