FUNGOID PESTS OF CULTIVATED PLANTS. 157 



As an epiphyte, the application of sulphur has been the only success- 

 ful remedy, or sulphur in combination with lime. 



Gard, Chron. May 15, 1886 ; 1847, p. 779 ; 1878, p. 74. Journ. R.H.S. 

 1878, p. 68. Thiim. Pih. Wein. p. 1, t. 3, f. 1. 



POWDERY MILDEW OF VINE. 

 Uncinula spiralis (B. & C.), PL XIV. fig. 13. 



American botanists are generally satisfied that this vine disease of 

 theirs is a fruitful development of the English vine disease, which we 

 only know, in the conidial form, as Oidium Tuckeri, for which reason, 

 therefore, it is entitled to some notice here. 



It forms white or greyish patches on the surface of the leaves, young 

 shoots, and fruit. This is composed of the interwoven threads of the 

 mycelium, from which afterwards arise short erect branches, the upper 

 portion of which becomes converted into a chain of conidia, the final one, 

 which is the oldest, falling away when mature, giving to the white patches 

 a still more powdery appearance. 



Towards the end of the summer the globose conceptacles make their 

 appearance amongst the mycelium, at first yellow, afterwards dark brown, 

 attached at the base by delicate threads. Encircling the base, a series of 

 spreading, straight, simple appendages radiate around the conceptacles, in 

 number from ten to twenty, the tips of which are hooked or spirally 

 twisted, and the lower part, next the conceptacles, coloured. The asci, or 

 sacs, within the conceptacles, enclose from four to six elliptical sporidia 

 (20x8-10^). 



Journ. JK.H.S. 1878, p. 68 ; Thiim. Pilz. Wein. p. 183 ; Grevillea, iv. 

 159 ; Gard. Chron. 1878, p. 74 ; Mass. PL Dis. pp. 93, 360, fig. 14 ; 

 Tubeuf, Dis. p. 176. 



In the United States another species of the same genus (Uncinula 

 subfusca) attacks the living leaves of Vitis Labrusca. 



AUSTRALIAN VINE MILDEW. 



Erysiphe vitigera (C. & M.). 



This is the vine mildew which in Australia corresponds to the powdery 

 mildew of the United States, and to our own Oidium Tuckeri. In its early 

 manifestations, and the conidial stage, it might be taken for Oidium 

 Tuckeri, and probably was so accepted before the discovery of the perfect 

 fruit. 



The first stage is the creeping mycelium and white mould, which 

 covers the leaves, wholly or in patches, and this is followed by the 

 presence, amongst the mycelium, of the little globose conceptacles, attached 

 at the base, and furnished with a circle of appendages or flexuous 

 threads, as in other species of Erysiphe, such as the one upon the Garden 

 Pea, but less distinct and more interwoven with the mycelium. The 

 receptacles contain four pear-shaped sacs or asci, each of which contains 

 two sporidia (18 x 9 ^u), which are elliptical and colourless. 



It was first made known and described in 1887. 



