GRAPE VINES SPOT. 



329 



leaf, and again when the grapes are thinned. Lime, calcined oyster-shells, Thomas's 

 phosphate, and coprolites are good applications to 

 vine borders which are not mechanically wrong in 

 texture, and a good dressing of a calcareous ferru- 

 ginous gravel, mixed with the soil as deeply as the 

 roots admit, is good for borders that are too close 

 in texture. 



Spot. There are two affections of the berries 

 of grapes which are termed spot. 1, Muscat of 

 Alexandria and Canon Hall Muscat are subject 

 to a small, uneven, whitish spot on the berries 

 while young, tender, and swelling quickly. On 

 the depressed patches a series of minute dots 

 shortly afterwards appears, and under the micro- 

 scope they prove to be a fungus, Glaeosporium 

 Iseticolor, which grows outwards, and its mycelial 

 threads traverse the interior of the fruit. The 

 occurrence of this form of spot is attributable to 

 sudden chills, such as admitting air too freely and 

 too late on a sunny morning, or after a period of 

 sunless weather, during which the house has been 

 kept very close and moist. The preventive, there- 

 fore, is careful attention to the ventilation (see 

 " Scorching "). 



2. Spot also appears on ripening or ripe Muscat 

 of Alexandria, Duke of Buccleuch, and other 

 grapes with skins highly susceptible of injury by 

 damp. Brown spots appear on the berries, and 

 spread rapidly. This disease is very disastrous, 

 often causing serious loss of fruit in a short time. 

 It also is associated with, if not caused by, Glaeo- 

 sporium Iseticolor in the half-ripe fruit, whilst 

 tfiat of the ripe fruit is probably Gla3osporium fructigenum. There is no remedy, but 

 it is advisable to remove and burn all affected fruits ; the best preventive is a free 



VOL. n. u u 



',X400 i-c{* 



Fig. 104. Ftmatrs PRODUCING SPOT ox TRAPES. 

 (From the Gardeners' Chronicle, Vol. VIII., 

 third series, page 657.) 



References: A and B, first appearance of 

 spot in grapes small whitish bruise-like 

 patches, from which the pulp beneath at 

 length recedes or contracts, and a depression 

 more or less extensive forms on the side of the 

 berry, as shown. C, five transparent cells of 

 the grape pulp at the base; skin of the grape on 

 the right and left, with orifice formed in the 

 thick skin ; and fungus threads bearing an 

 abundance of spores. D, tops of spore-capped 

 threads enlarged 400 diameters. E t single 

 spore, enlarged 1,000 diameters. 



