GRAPES UNDER GLASS 203 



dener. In a grapery devoted exclusively to grape-growing, it 

 should never be seen, but, since gardeners must often grow 

 other plants in the grapery, mealy-bug sooner or later appears 

 and is often hard to dislodge. It is best repelled by removing 

 the loose bark on the trunks which harbor the pest and then 

 washing with kerosene emulsion. When this becomes neces- 

 sary, not only the vines but the rafters and all parts of the house 

 should be sprayed with the emulsion. 



Red-spider is another pest usually found in the grapery, but 

 it thrives only in a dry atmosphere and is easily gotten rid of 

 by syringing. As soon as red-spider appears in a house its 

 appearance is usually known by the reddish tinge on the foliage ; 

 syringing should be kept up until the pest is disposed of, keep- 

 ing the house damp in all except dull weather. Syringing is 

 done only when plenty of air can be given and when it can be 

 followed by sunlight so that the water remains on the vines 

 as short a time as possible. 



Thrips, another small insect, is sometimes troublesome but 

 not often and is now easily controlled by applications of nicotine. 

 Much care must be taken in the application of nicotine late 

 in the season, otherwise the fruit will be injured. 



The only fungous disease of the grape troublesome in the 

 greenhouse is mildew. Mildew is usually brought on by a 

 sudden change of temperature or by draughts in the grapery. 

 Gardeners are of the opinion that east winds, in particular, 

 give unfavorable conditions for mildew and prefer to open the 

 ventilators to the west. If taken in time, mildew is easily 

 kept in check by preventing the conditions which favor it, 

 and by dusting the vines in dry sunshine with sulfur. 



