DISEASES OF PLANTS. 



21 



but taking care not to use too much ; and it should be used 

 only when the pipes are warm. There should be a good 

 supply of moisture at the same time, but not too much 

 heat. The green fly, which makes its appearance in spring 

 on the young flower-buds, may also be destroyed by tobacco- 

 smoke. 



The brown and white scale and mealy-bug I keep 

 under by constantly sponging the leaves and bulbs with 

 water ; the white scale is very troublesome if not looked 

 after. Cattleyas are very subject to this ; the following 

 recipe for destroying these insects was given me by Mr. 

 Veitch of Exeter, who is a very successful grower of Or- 

 chids, viz. to one gallon of rain water add eight ounces of 

 soft soap, one ounce of tobacco, and three table-spoonsful 

 of turpentine ; stir well together, and leave the mixture for 

 forty-eight hours ; then strain it through a cloth : what 

 you have to spare must be bottled off. It is necessaiy to 

 rub the plants over two or three times, if they are much 

 infested, but once will be sufficient in most cases. 



Diseases or Rot in Orchids. 



Orchids are subjected to disease in their leaves and 

 bulbs, especially during the damp months of winter. The 

 rot, which is apt to assail the thick, fleshy bulbs, is caused 

 by too much moisture in the house ; sometimes the drip 

 from the glass will fall on the crowns of the bulb, and they 

 soon rot. Steam is also very bad in a house during the 

 winter, particularly to such plants as Cattleyas, Peristerias, 

 Odontoglossums, and any other Orchids that have fleshy 

 bulbs. When the rot takes the bulbs it should be seen to 

 at once, and may be easily stopped by cutting the diseased 

 part entirely away with a sharp knife. No portion of the 

 diseased or decayed bulb should be left ; the wound should 

 then be filled up with sulphur, keeping it dry. When the 



