DISEASES OF THE VINE. ] 581 



virulent at the time of flowering and until the berries 

 have reached the size of a small pea. It makes its 

 appearance usually in April, on the tender foliage which 

 becomes blotched with yellow pellucid spots, with a 

 whitish or silvery efflorescence on the corresponding part 

 of the under surface, but this whitish efflorescence is 

 sometimes absent. The disease spreads with alarming 

 rapidity, and may infect all the leaves of the young shoot, 

 which soon dry off and take a light brown colour. The 

 infection reappears in autumn, and then the yellow or 

 yellowish blotches have an angular form, with a silvery 

 lustre on the under surface, and whitish tufts of fructifica- 

 tions, especially along the nerves. The vine deprived 

 of its foliage so early in spring remains stunted, the 

 canes do not develop well, so that not only that year's 

 crop is lost but the promise for next year is seriously 

 affected. 



However, the principal injury is caused to the flowers 

 and the fruit. The bunches are attached chiefly, and 

 with great virulence, at the time of flowering, but may be 

 attacked some days before the flowers begin to bloom, 

 although the most dangerous period, at least for this 

 Island, is from the moment that the flowers begin to 

 bloom until the berries have reached the diameter of 

 about 3 m.m. 1 he extremities of the bunch become 

 flaccid, assume a whitish or ashy mouldy appearance, and 

 dry off, the infection progressing quickly and may involve 

 the whole of the bunch. So rapid is the progress of 

 infection that one day there may be only slight traces 

 of disease, and in two days not a single bunch remains 

 unaffected. 



A form of vine-blight in which no fructifications are 

 produced may attack the terminal berries of a bunch, or 

 the entire bunch, when the berries have reached the size 

 of a large pea, that is late in June or in July. These ber- 

 ries shrink and become wrinkled, take a light chocolate 



