GRA 



[ 445 ] 



GRA 



The most injurious time for an un- 

 natural disparity of temperature in the 

 air and soil to occur is at night; for, 

 as was justly observed by the late Mr. 

 Knight, an ill effect of high temperature 

 during the night is, that it exhausts 

 the excitability of the tree much more 

 rapidly than it promotes the growth, 

 or accelerates the maturity of the fruit, 

 which is in consequence ill supplied 

 with nutriment at the period of its 

 ripening, when most nutriment is pro- 

 bably wanted. The Muscat of Alex- 

 andria, and other late grapes, are, 

 owing to this cause, often seen to wither 

 upon the bunch in a very imperfect 

 state of maturity; and the want of 

 richness and flavour in other forced 

 fruit is often attributable to the same 

 cause. The Frontignans are among 

 the varieties apt to shrivel under 

 great disparity of temperature between 

 the roots and branches. 



Somewhat allied in its causes to 

 shrivelling, is that unsightly imper- 

 fection where the berries do not come 

 to maturity at the point of the bunches, 

 leaving from five to ten quite colourless 

 and sour, though others on the same 

 bunch are fine and large. In such 

 case the remedies are to give more 

 heat and air, keeping the border warm- 

 er than before, and to avoid cold damps 

 in the house ; leave as much foliage as 

 can be exposed fully to light. The 

 leaves removed must be by little at a 

 time. In thinning, clip off a few berries 

 at the lower extremity of the bunch ; 

 the rest will swell better. 



Slianklny is an ulceration, or gan- 

 grene, attacking the footstalks of the 

 bunches, and appears to be occasioned, 

 like shrivelling, by the temperature of 

 the soil being too much below that in 

 which the branches are vegetating ; 

 and, consequently, the supply of sap to 

 the grapes is much diminished, and 

 the parts which thus fail of support 

 immediately begin to decay ; this is an 

 effect always the consequence of a di- 

 minished supply of sap, apparent either 

 in the leaves, flower, or fruit. The 

 disease, like every other putrefaction, 

 does not advance rapidly unless there 

 be much moisture in the atmosphere. 



The coldness of the soil causes this 



torpidity in the action of the root ; and 

 this, perhaps, at the very period when, 

 the greatest demand is made upon it to 

 sustain the excessive perspiration which 

 is going on in the leaf, and to furnish 

 fresh matter for elaboration ; to both 

 which ends it is frequently quite inad- 

 equate, owing to drenching rains. If 

 the young fibre be examined at such 

 inclement periods, it will be found 

 somewhat discoloured ; and, in some 

 cases, quite rotten. Shanking, we con- 

 ceive, is generally caused by the un- 

 natural disagreement of temperature 

 between the root and top, independent, 

 in the main, of the question of moisture. 

 It generally occurs with vines which 

 have been somewhat forced ; seldom 

 on open walls seldom with vines 

 forced in pots or tubs. The obvious 

 prevention of shanking is securing a 

 congenial relative temperature to the 

 roots and foliage. 



Rust comes upon the berries in the 

 form of a rough, rusty appearance of 

 their skins, which have, in fact, become 

 thick and indurated. Some think it 

 arises from their being handled, or the 

 hair of the head touching them ; but 

 the disease is often too general to 

 admit of this topical explanation. We 

 believe it to arise from an over-heating 

 of the vinery, however unintentional, 

 whilst the grapes were young, and thus 

 tending to force them to a premature 

 rapidity of growth. Any excessive 

 pressure upon the cuticle, whether 

 from within or from without, causes its 

 thickening. This considerable eleva- 

 tion being succeeded by a sudden re- 

 duction of temperature, will almost 

 certainly induce the disease. 



The Spot affecting the berries seems 

 to be the same disease as shanking, 

 only affecting a different part. Like 

 this disease, it is a gangrene, and is 

 probably occasioned by an irregularity 

 in the supply of moisture and vicissi- 

 tudes of temperature, but especially if 

 one of the extremes is much below the 

 degree of heat most favourable to the 

 healthy growth of that plant. Muscats 

 are particularly liable to the spot. Our 

 opinion that sudden vicissitudes of 

 temperature are the causes of this 

 disease, seems to be well sustained 



