576 [ DISEASES OF THE VINE. 



size of small peas. The action of bees and other insects 

 which visit the flower, is said to cause the bunches to 

 shank, but there is no positive proof of this, although 

 these insects may break off a few of the delicate flowers 

 of the vine here and there, in their busy flight. On the 

 other hand shanking is often ascribed to defective fertili- 



o 



zation, in which case the visits of pronubal insects should 

 prove rather useful than detrimental. Moreover, there 

 are many varieties of vines, such as the Muscats etc., 

 which have a natural and invincible habit of shanking, and 

 therefore in their case a shanky bunch is more normal 

 than otherwise. The habit of shanking in very vigorous 

 vines is sometimes markedly persistent, recurring year 

 after year, and occasionally the vine becomes quite 

 sterile. This habit may be corrected by thoroughly 

 draining the land, by frequent trimmings, by late pruning 

 which provokes some bleeding from the exposed tissues, 

 and by exposing the bunches to the action of the sun as 

 soon as they are put forth by the plant, that is long 

 before the blooming period. 



Weak buds. This condition is often complained of, 

 and is noted both on the terminal bud of the cane which 

 has been pruned long, as well as on the spur retained in 

 short pruning, and is often seen also on lower buds. 

 These weak buds do not show signs of parasitism, and 

 seem quite healthy and good, but develop into very weak 

 shoots, with short internodes and often with rickety 

 leaves, exactly as in the initial stages of roncet. The 

 causes of this diseased condition are unknown. It has 

 been ascribed to traumatism, that is to bruises produced 

 by rubbing or striking against stones and other hard 

 objects, but in the case of the terminal buds it is general- 

 ly due to the mistaken method of pruning, according to 

 which the cane is cut just above the terminal bud. The 

 pith is thus laid open close to the bud, which cannot but 

 suffer the consequences of a partial drying up of the 



