198 ORAPE CULTURE AND 



the vine, sometimes it takes all, while in another season it 

 may be healthy again, ripen its fruit, and have healthy leaves. 

 The leaves become spotted, like if drops of hot water had 

 fallen on them, becoming livid at first, they soon change to 

 almost scarlet, and finally drop; the fruit, if small, shrivels 

 up and dries; if larger, it becomes marbled with dull gray, 

 and does not attain full size. I think some injury to the 

 vine, either by injudicious and severe pruning, or by tearing 

 the roots with the plow, or by gophers or other animals, 

 mostly the cause of it. The bluestone remedy has been 

 recommended against it, and may prove effectual. It is pre- 

 pared as follows: Dissolve in 25 gallons of water 16 Ibs. of 

 copper sulphate (bluestone), also shake 20 Ibs of quicklime 

 with seven and a half gallons of water into a milk of lime, 

 which then rinse with the bluestone solution; this will pro- 

 duce a light blue mixture, which should be frequently stirred 

 during use. This is sprinkled on the vines by means of a 

 little broom. Care should be taken not to sprinkle the 

 grapes. It is recommeded by Professor Millardet also as a 

 remedy against peronospora, and Prof. Hilgard thinks it may 

 be a remedy against mildew. I think that an application of 

 this solution, applied as a whitewash to the body of the vine in 

 the winter, would be very beneficial as a prevcntative of 

 diseases, and also destroy a great many injurious insects and 

 their eggs. 



BLACK KNOT. 



This disease, which appears sometimes on the trunk of the 

 vine; sometimes on its head or below a spur, is mostly due to 

 external injuries, either too short or injudicious pruning, 

 bruises, breaking of the vine, or severe frosts; in short, by 

 some cause which effects a bursting of the sap vessels. For 

 instance, if all the young growth of the vine is so badly frosted 

 that even the wood is affected, and the dormant buds killed, 

 there is nothing left to conduct the flow of sap, and stagnation 



