PLASMOPARA 121 



the loss of the foliage, and the entire plant is prevented from 

 preparing the store of food necessary for next season's vigorous 

 growth. 



Conidiophores slender, branched near the apex, ultimate 

 branchlets pointed, straight, conidia elliptical, not papillate 

 at the apex, very variable in size, smallest 8x 12, largest up 

 to 17 X3o /A. Oospore subglobose, wall brown, thin, smooth 

 or slightly wrinkled, 30-35 p diam. 



In many vineries the disease has been observed to first 

 appear in one particular part of the house ; this has been 

 traced to draught or comparative lack of light and ventilation 

 at that particular spot. 



Spraying at intervals with dilute Bordeaux mixture until 

 the grapes are set will check the spread of the disease. 

 During the winter, when the vines are resting, thoroughly 

 drench the plants, soil, and every part of the house with a 

 solution of sulphate of iron. Remove all diseased leaves, and 

 be particular to collect and burn all fallen leaves, etc. 



Massee, Gard. Chron., July 21, 1894. 

 Viala, Les Malad. de la Vigne> p. 57. 



Cucumber and melon mildew (Plasmopara cabensis, Hum- 

 phrey) often does serious injury to cucumbers, melons, and 

 other plants belonging to the gourd family in the United 

 States, and has also been recorded on cucumbers in this 

 country. It forms a delicate mildew on the under surface of 

 the leaves of a delicate lilac colour. The patches are small 

 at first, but gradually encroach on each other, forming large 

 areas. Affected leaves become yellow and shrivel up. The 

 disease spreads rapidly during hot, moist weather, and is 

 more prevalent on plants grown in the open than on those 

 under glass. 



Care must be taken not to confound the present disease 

 with the cucumber powdery mildew, caused by Erysiphe 

 polygoni (D. C.), as the two require different methods of treat- 

 ment respectively. 



Conidiophores repeatedly branched, ultimate branchlets 

 pointed, straight, conidia elliptical, 25-32 x 18-20 fj.. Oospore 

 unknown. 



Spraying with Bordeaux mixture at intervals of about ten 

 days is said to hold the fungus in check. 



Plasmopora entospora (Schroter) forms small, whitish tufts 



