174 TREATISE ON THE CULTURE AND 



1/et water them with the grounds of the lime, which will 

 make the trees look very unsightly, and also injure the leaves. 



When aphides are numerous at the ends of the shoots, the 

 leaves there will be curled up ; these should be all stript off, and 

 the insects crushed with the foot. 



Of the Acarus. 



The Acarus, or Red Spider, is one of the most de- 

 structive insects that can infest plants, particularly in forcing- 

 houses. 



These insects have no wings, and the female is oviparous. 



There are no less than 82 species of this genus. The 

 acarus is very common on trees, particularly the currant, on 

 the fruit of which it is frequently seen running. 



These insects attack the vines, nectarines, peaches, and 

 cherries ; and forced French beans are very subject to their 

 depredations, as are also peaches and nectarines on the natural 

 wall, in hot weather. Melons in frames are very much in- 

 fested with them. I once saw a ridge of melons, of seventy 

 lights, so much injured by them, that when the fruit was full- 

 grown, it v/as good for nothing, and the stems and leaves 

 were completely exhausted of their moisture by these insects 

 feed'ng on them. They are equally hurtful to most exotics in 

 hot-houses. 



The best thing that I know for destroying these perni- 

 cious insects is moistLire ; which will also destroy many other in- 

 sects in hot-houses. 



Frequent watering of wall-trees, standards, &c. with lime- 

 water (the making and using of which is described in the di- 

 rections for destroying the aphis), and throwing it plenti- 

 fully on the underside of the leaves, where the acarus is ge- 

 nerally found, will in a short time extirpate that destructive 

 insect. 



For plants, &c. in hot-houses, I would recommend using 

 water only, and in the following manner: 



Between three andrfour o'clock in the afternoon, fill the 

 barrow engine with soft water, or such as has been exposed to 

 the sun all day and wheel it along the foot-paths of the house, 

 where they are wide enough to admit it, and sprinkle all the 

 plants, pressing your finger on the top of the pipe to spread 

 the water like a fine shower of rain, playing also against the top 

 lights and shelves till the water stands an inch deep in the paths 

 of the housed. If you cannot conveniently get the engine into 



* I hare lately seen a small copper engine, made by Mr. Philips, engine- 

 maker, Blackfriars road, which answers very well, when a barrow engine 

 Uiiiipot be got into the house. 



