158 BEAUTIFUL FLOWERS 



middle of April, the cultivator might practise vaporisation once a 

 month until the middle of October. He may appear to be working 

 in the dark. He may not see any insects, and he cannot follow 

 all the movements of the vapour ; but he may depend upon it that 

 there are insects lurking in some corners or crannies, and be equally 

 sure that the vapour will search them out and destroy them. 



Another great help in keeping down insects under glass is to 

 provide plenty of atmospheric moisture, and to apply it vigorously. 

 For example, if there are roof plants, souse them once a week with 

 water applied forcibly through a syringe. The water will cleanse the 

 plants on to which it is driven, and, falling in a heavy shower 

 on those on the stages below, will cleanse and freshen them also. 

 Mealy-bug, red-spider, and green-fly are all so seriously incom- 

 moded by these vigorous washings that they never get a chance to 

 settle down. It is a dry atmosphere, and freedom from bustling, 

 that gives them their chance. 



Plants that are subject to the attacks of leaf-miners indeed, 

 plants that are attacked by any kind of insect may be protected 

 by being sprayed over every three weeks or so with a paraffin-oil and 

 soft soap emulsion, which may be made by boiling a pint of soft soap 

 in two pints of water, stirring in, after removal from the fire, half a 

 pint of paraffin-oil, and diluting in five gallons of water. The 

 mixture should be thoroughly worked up by filling a syringe from, 

 and emptying it into, the vessel repeatedly. It is best sprayed 

 lightly on the plants towards evening. 



Fungoid Enemies. There are several fungi which attack indoor 

 plants, but mildew is much the most common. It coats the leaves 

 with a grey powder, and they lose their substance and fall ; the 

 plant becoming thoroughly unhealthy, or even dying outright. 

 These fungi, and particularly mildew, are commonly the result of 

 faulty ventilation. They are almost certain to appear if a house is 

 subject to cold draughts, as is the case sometimes when the venti- 

 lators are opened at the side on which the wind is blowing. But 



