172 



THE GREEN-HOUSE, 



house. Washes of soap-suds and of soft soap and 

 sulphui' have been recommended for destroying it ; 

 but things must have been in a very neglected state 

 when it becomes too numerous to be picked off by 

 hand, or brushed off with a brush and a little warm 

 water. From the under sides of the leaves of the 

 orange tribe and other plants, it may also be washed 

 off with a sponge. 



The acarus, or red spider, is the most pernicious 

 of all the insects which infest plants ; but happily 

 there is a specific antidote for this enemy, as certain 

 in its effects as sulphur is in curing the itch, the ulcers 

 of which in the human body are infested by another 

 species of acarus. This is the application of water 

 to the leaves of plants infested by this insect. In 

 common cases water may be applied liberally from 

 the rose of the watering-pot, or from the watering- 

 engine or syringe ; and in cases where this mode 

 might over-water the roots, water must be applied in 

 the form of steam, by watering the flues after they 

 have been heated by a brisk fire, or by raising the 

 temperature of the house in a cloudy day, or in any 

 afternoon or evening, to 50° or 60°, and then water- 

 ing all the paths and floor where it will not injure 

 the plants. Other modes might be mentioned for 

 generating steam for the destruction of these insects ; 

 but they are never so prevalent in a green-house as 

 they are in hot-houses, and other forcing-houses, and 

 even in cucumber and melon frames, and therefore 

 the less care is requisite to destroy them. 



