56 DISEASES AND INSECTS. 



Where the spider is very plenty, a little flower of sulphur 

 may be dusted over the foliage to advantage. 



A good preventive is to place a pan upon the flue of the 

 greenhouse, fill it with water, and dust into it a few hand- 

 fuls of flower of sulphur : the fumes arising from this when 

 the water becomes heated are death to the spider. Care 

 must be taken not to allow these fumes to rise upon very 

 delicate plants, as they are sometimes injurious. 



The common remedy of putting sulphur on the flue 

 should^be used with great caution, as, though sure death to 

 the spider, it often kills the plants, or causes them to lose 

 their leaves. 



In house-culture, the simplest remedy for spider is syrin- 

 ging, or, where this cannot be done, frequent sponging of 

 the foliage with pure water, or sulphur and water. 



GREEN-FLY. 



The green aphis, or fly, so common in greenhouses, is 

 often found on the foliage of bulbs. 



The easiest and best remedy is a gentle fumigation of 

 the greenhouse, or of the infected plant under a barrel, as 

 in the ordinary treatment of house-plants for this pest. 



