408 



Journal of Agriculture, Victoria. [10 July, 1917. 



Less damage is done to leaves, though they may be more or less 

 severely riddled with black-edged shot holes of varying size, but usually 

 small ; scars occurring on the stalk and veins may cause contractions 

 and distortions of very variable nature, which twist and deform the 

 leaf. 



In case of early attack, the floral organs may be damaged and 

 blackened as though scorched by fire. Even if the visitation be less 

 severe, the setting of the fruit may nevertheless be seriously interfered 

 with. Later on either stalk or berry may be attacked. In the former 

 case a portion, or even a whole bunch, may be cut off or damaged to 

 such an extent that the berries remain small, with little sugar in them. 

 On the berry black bird's-eye like spots are formed, the centre be- 

 comes grey, or greyish-pink, and sinks in, but not so deeply as the 

 cane scars; these spots are surrounded by a black edge. Irregular 



tension often causes affected berries 

 to burst. The quality of the wine 

 suffers quite as much as the quan- 

 tity, the composition of the must 

 being seriously interfered with ; pro- 

 ducts are also secreted by the fungus 

 which alter the flavour of the wine, 

 often causing it to be faulty in con- 

 stitution and keeping qualities. 



The most serious damage usually 

 occurs early in the season, before 

 the blossom, and vines badly attacked 

 at this stage often lose their whole 

 crop, the embryo bunches ajjpearing 

 as though badly charred (see 

 Fig. 1). When the fruit is about 

 half its full size, grave harm may 

 also be done, the appearance of table 

 and drying grapes being more or 

 less damaged, and the quality of 

 wine seriously impaired. 



Damage is not confined to the 

 season of the outbreak ; the crop of 

 the following year often suffers also. 

 It. is, in fact, very generally recognised that during the year following 

 a severe attack, even though climatic conditions do not favour the re- 

 appearance of the fungus, the vines make poor growth and show little 

 fruit at blossom. The vine seems to have a languishing vegetation, and 

 benefits much by stimulation with nitrogenous manures. 



Life History of the Fungus. 

 That Manginia ampelina is a very old fungus is proved by the descrip- 

 tion given of it by agricultural writers of ancient Rome. It differs from 

 most of the vine fungi, such as Oidium, Uncinula spiralis. Berk et Curt, 

 Downy Mildew, PJaitihojKira vifirola (B. et C.) de Toni, Black Rot, 

 Guignardia hidwelii (E.) V. and R., &c. , in that it has always existed in 

 Europe, whereas these other fungi are all of American origin, and were 

 unknown in Europe seventy years ago. 



Fig. 5. 



Blackened and mottled appearance 

 of vine canes <;aused by Oidium — 

 quite distinct from Anthracnose scars 

 — compare Fig. 4. After H. Mares. 



