262 DISEASES OF CULTIVATED PLANTS 



Conidial form. Sterile hyphae prostrate, fertile ones erect, 

 forming dense grey tufts, simple or slightly branched, ends 

 spinulose, bearing heads of conidia; conidia subglobose with 

 usually a minute apiculus, almost hyaline, 10-12 \i. Vines 

 grown under glass alone suffer from the disease in this country, 

 and as the fungus can only thrive in a very damp atmosphere, 

 early morning ventilation is of the utmost importance. Spray- 

 ing with sulphide of potassium arrests the disease ; and when 

 the fungus has once occurred, a thorough spraying of the 

 plants 7vhen resting, and of the entire house, with a solution 

 of sulphate of iron is advisable. 



Infected leaves and fruit should at once be removed. 



De Bary, A., Morphol. and Physiol, of Fungi (Engl, ed.), 

 p. 224. 



Istvanfn, Ann. Inst. Ampel. Hbngr., 2 (1902). 



Snowdrop mildew. A fungus named Schrotinia galdn- 

 thina (Ludwig), but which may prove to be nothing more than 

 S.fuckeliana | 1 >e Bary), often attacks snowdrops as they appear 

 above-ground. The leaves and flowers, instead of developing 

 properly, are much contorted and completer) covered with a 

 dense felt of grey mould. Numerous minute black sclerotia 

 are formed on the diseased leaves and flowers, and also on 

 the outer bulb-scales. The mould is of the usual Botryth 

 type, but the spores differ slightly in size and form from 

 those of other known species, whether this variation is due to 

 the host upon which it grows, or is of specific importance, 

 remains to be proved. The ascophore condition is unknown. 



The conidial condition was first described as Botrytis 

 galanthina (Berk, and Broome). Hyphae shortly branched 

 upwards, branchlets thickened at the tips, coloured ; conidia 

 obovate, 15 iSx 10-11 /', forming heads, springing from 

 slender sterigmata. 



Plants that are once attacked never bloom, but produce the 

 disease year by year. The bulbs of all diseased plants should 

 be removed and destroyed. Remove the upper two inches 

 of soil from places where the disease has existed, and replace 

 by fresh soil mixed with a small quantity of powdered sulphur. 



Ludwig, Lehrb. dcr under. Kryptogamen, p. i^. 



Douglas fir blight. -A grey mould that often kills large 

 numbers of seedling conifers of different kinds, was at one 



