INSECTS, FUNGI, PLANT DISEASES. ETC. 



163 



expand, using a solution of sulphate of copper. When the 

 blossoms have fallen repeat the spraying with the Bor- 

 deaux mixture, and make two or three applications if the 

 season is wet. 



Laestadia Mdwelli (Ell.), Via. and Rav. Black rot of the 

 grape. This disease 

 a 1 1 a c k s both the 

 fruit and the leaves, 

 the former most se- 

 verely. When about 

 full grown there ap- 

 pear on the grapes 

 spots of a brown or 

 purple color, which 

 in a few days extend 

 over the entire sur- 

 face, with the center 

 somewhat d a r k e r. 

 Black pimples over 

 the diseased part are 

 characteristic fea- 

 tures of the fungus. 

 The fruit soon 

 shrinks up and re- 

 mains on the vine for 

 a period as late as 

 winter. On the leaves 

 the spots are reddish 

 brown dispersed be- 

 tween the veins. The disease is detected here some days 

 before the attack is made on the fruit. 



Since the fungus makes its appearance so late in the 

 season after the fruit is well advanced, it becomes rather 

 a difficult problem to destroy the disease if the spraying 

 is postponed, without staining the grapes. It is, there- 



Fig. 62— Laestadia huhnW ( Ell ). Via & Rav. 

 Div. Botany, U. S. Dept. Agri. 



