57 



sulphur or other fine sulphur-powder. This should be applied 

 by means of a sulphur bellows or sulphurator and is best put 

 on early in the morning when the foliage is damp. It is 

 possible that a lime sulphur solution such as is used for 

 American Gooseberry Mildew (see Leaflet 195) may be useful, 

 but no records as to the use of this fungicide for vine mildew 

 are available. Bordeaux Mixture, although used with success 

 on the Continent for the other vine mildew (Downy Mildew), 

 is not regarded as satisfactory for keeping down Powdery 

 Mildew. 



2. Under glass. Mildew may very largely be prevented by 

 careful attention to cultural details. The atmospheric c ndi- 

 tions of the house, which to> a great extent can be controlled 

 by careful ventilation, are most important. Air should be 

 given early and gradually increased as the temperature rises; 

 draughts should always be avoided. During dull, wet periods 

 a buoyant atmosphere should be maintained by increased fire 

 heat and by giving some ventilation for at least a short perio4 

 of the day. The same or even more care should be exercised 

 as in the open with regard to the thinning out and pinching 

 back of laterals so that plenty of light and air are admitted. 

 The maintenance of a steady temperature and the avoidance of 

 dryness at the root also tend to prevent mildew from obtaining 

 a footing. 



If mildew appears sulphur should at once be applied. The 

 safest method is to blow a fine sulphur powder on to the foliage 

 by means of a sulphurator. The old fashioned plan of painting 

 the hot water pipes with a mixture of milk and sulphur and 

 then heating them steadily for a few hours is effective, but the 

 work should be entrusted only to an experienced hand. By 

 far the most effective method is the use of the apparatus known 

 as a Sulphur Vaporizer. With this apparatus Vine Mildew 

 can be completely suppressed, but here again great caution is 

 needed and the instructions accompanving the vaporizer should 

 be strictly attended to. In the case of these last two methods, 

 any ferns and other plants with delicate foliage which are 

 present in the house should be removed during the vaporizing 

 operation. 



REVERSION ' OR NETTLEHEAD OF BLACK 

 CURRANTS. 



(Cause Unknown.) 



Introduction. One of the most serious diseases of Black 

 Currants at the present time is that termed " Nettlehead " or 

 " Eeversion." Owing to its ravages hundreds of acres of Black 

 Currants have ceased to bear as they did formerly and many 

 have become so unprofitable that the bushes have been grubbed 

 up, The precise nature and cause of the disease are still 



