100 THE SHANKING OF GRAPES : CAUSES OF 



amount of properly developed leaves ; so that an over-crop of fruit is 

 tantamount to a scarcity of leaves and overstraining of the powers of 

 the plant, and the result is shanking to a very serious extent. 



2. The destruction of the foliage by red-spider, burning, or other 

 causes, which is equivalent to a scarcity of leaves. 



3. The stripping-off of a great quantity of fully-developed leaves 

 at one time, as is frequently done by those who neglect timely stopping, 

 which interference with the foliage affects, in a corresponding degree, 

 the action of the roots, and leads to shanking. 



4. Chills or sudden changes of the temperature of the house, such 

 as may be experienced on the change or approach of colder weather 

 a very frequent occurrence in this climate ; the evil arising from 

 neglect to reduce or regulate the amount of ventilation, or to use the 

 heating apparatus, which, at such periods, is often, but erroneously, 

 dispensed with. 



5. The roots getting into a cold subsoil, or the border becoming 

 sour and soddened, whereby the young spongioles of the roots are 

 destroyed. 



6. Planting in borders composed of too rich materials, containing 

 too much organic matter ; in consequence of which the Vines grow 

 with great luxuriance, but seldom ripen the wood properly. The 

 roots formed, although plentiful, are very soft and spongy ; they do 

 not acquire firmness, but decay during the winter season, and, conse- 

 quently, the next season a fresh supply of rootlets has to be produced ; 

 and then, when the strain upon the energies of the Vine takes place 

 by the demands of the advancing fruit crop, the roots are not in a 

 proper condition to meet it, and, as a result, shanking ensues. This 

 late production of roots, their decay in winter, and the subsequent 

 shanking, may go on year after year. 



7. Excessive dryness at the roots, such as to cause injury to these 

 organs. If the border is allowed to get over-dry whilst the Vines are 

 in full growth, the young roots become paralysed, and if they are then 

 deluged with water, they will, as a consequence, be certainly destroyed. 



These are several of the causes that directly or indirectly lead to 

 shanking, acting either singly or in combination ; yet, when a case of 

 shanking appears, it may be very difficult to trace it to its true origin, 

 or to apply a remedy. Many of the above-named causes may be 

 avoided by good management, as, indeed, they all should ; but where 

 the roots are at fault, either through being in a border which is too rich 

 or too wet and sour, the only remedy that can be adopted is to take 

 the Vines up carefully and renew the border, taking care, if in a low 

 or damp locality, to introduce a greater proportion of porous materials 

 than before, so as to secure good drainage, and then to replant them. 



Adventitious, or Air-roots, fig. 39. These are so called from their 

 being^produced on the stem of the Vine, and their being suspended in 

 the air like so many threads, as represented by fig. 39. They are of 



