10 July, 1917.] Anthracnose or Blink SjM)t oj the Vine. 



407 



alone seems to l>e caused by the true Blaok Spot, or Manginia Fungus. 

 it forms tlie subject of the present article. Concerning Punctuate and 

 Deforming Anthracnosis, various opinions have l>een expressed. Ac- 

 cording to Chappaz, tliey are merely manifestations of the rather ob&cure 

 disease known in Southern France as " Court-noue " and are seldom of 

 any gravity. 



Maculate Anthracnosis, the disease we know as Black Spot, is un- 

 doubtedly caused by the fungus now botanically known as Maiu/inia 



fi»i pe/iitfi, V. and P.,* 

 which may attack the 

 young canes almost imme- 

 diately after the break- 

 ing of the buds in spring. 

 The earliest manifesta- 

 tions consisti of small, 

 isolated. light-brown 



spots, mainly on tiie 

 green bark of the young 

 shoot. They remind one 

 of a miniature bruise, 

 rather smaller than a 

 pin's head at first. 

 These spots become 

 darker and increase in 

 size, mainly lengthwise, 

 assuming irregular sha]3es 

 and ultimately forming 

 the scars characteristic 

 of the disease ; these sink 

 in as they spread, and 

 eat more and more 

 deeply into the woody 

 tissues, sometimes pene- 

 trating as far as the pith 

 (Fig. 3). Should several 

 scars form close to one 

 another the can© may be 

 so weakened as to be 

 easily broken off by wind. 

 In early summer the 

 centre of the scar is 



Fig. 1. 



Anthracnose sears on ripened wood on the vine in 

 winter. After Viala and Pacottet. 



usually of an ashy-pink colour, surrounded by a black rim ; this is char- 

 acteristic. The pinkish appearance of the centre is caused by the sum- 

 mer spores or conidia, which are produced in enormous numbers at this 

 season. The canes tiwist as though burnt; the partial destruction of 

 vessels interferes, with the sap supply, and the resulting starvation causes 

 the canes to become stunted, and to send out numerous laterals and sub- 

 laterals, which give the vine a shrubby appearance. Sears varying in 

 shape and size are thus formed on tbe canes, the appearance of which 

 in the winter following is shown in Fig. 4. 



• This fungu*; was formerly known by the n.-nne^ of Sphacetoma ampetinc and QUeosporum 



ampelophayum. 



