1 



JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



In such cases dusting with dry sulphur is likely to be the most 

 effectual treatment. In America the application of the ammoniacal 

 solution of carbonate of copper is recommended. 



QreviLleOy xvi. 10. 



Apple-twig \Yhite Mildew. 

 SpluerotJieca malt (Duby). 



A century ago one of the fungi closely allied to that of the Rose and 

 the Hop was imperfectly described in France under the name of 

 Erysiphe viali, but very recently it has been revived by Dr. Magnus, who 

 has seen and figured one of the conceptacles. It was said to be broadly 

 eftused ; the thin arachnoid threads of the mycelium interwoven ; the 

 conceptacles rare, and scattered, subglobose, rugulose, and black. 



The mould already described here under the name of Oidium 

 farinosum appears to be the mycelium and conidia of the above fungus, 

 but at present the more perfect and complete condition with the con- 

 ceptacles has not been met with in this country. In this instance we 

 appear to have a " perennial mycelium in the host plant, which grows along 

 with the shoot each season, stunting its growth and eventually killing 

 the tree." (Fig. 1.) 



Journ. B.II.S. (1902), xxvi. p. 737, fig. 310; Duby, Bot. Gail. 869. 



Fruit-tree Pustule. 

 Eutypella prunastri (Pers.). 



This compound Splicer ia is only parasitic in the early stage, when 

 spermogonia are evolved in tendrils through punctures of the bark. No 

 one has seen the complete or true Eutypella stage, except on dead tissues. 

 In this condition the perithecia are clustered together in definite pustules, 

 some five or six, with long converging necks, which are sulcate or grooved 

 at the extremity or ostiolum. The fructification is contained within the 

 perithecia, consisting of eight sporidia, enclosed within a transparent 

 MOU8, of which there are several. The sporidia are cylindrical, curved, 

 and but slightly coloured (6-8 x 1! p). 



Ttit spermogonia, which are developed earlier, ooze out in tendrila 

 from the mouths of the receptacles, and are known in this stage under 

 bhe name of Oytispora rubescensy. they are not more than half the length 

 of the conidia. It is reported that this is a wound parasite, and enters 

 through wounds made by pruning, finally causing discoloration 

 in the centre of the stem (see figs. 2 and 8). The trees will continue to 

 grow for several years after infection. 



Destructive to Apple and other fruit trees, especially Plum and 

 Cherry. 



Sacr. Syll. i. 566; 0ool< /A/A/,-. No. 2460; Juiim. B.E.S. (1902), 

 ml p. 742, fig. 818; Z bid. xwii. pp. 691, 986,1152; Gard. Ghron. 1908, 

 ... 2:i:». lig. SO ; lirrlcsc Icon. iii. pi. 85. 



