INSECTICIDES 131 



from a recurrence of the trouble, BO that preventive measurei are 

 justified even though no sign of the enemy is apparent ; indeed, 

 many gardeners consider the use of insecticidal solutions advis- 

 able just to make sure that no trouble comes. Apply powders 

 when the foliage is a little damp. Practically all insecticides, 

 solid or liquid, should be used when the sun is not shining 

 brightly. If rainy weather follows the application it may be 

 necessary to repeat it, but at all events one spraying is seldom 

 satisfactory, for few insecticides can kill the vitality of eggs not 

 yet hatched. Syringe lightly and often, rather than hope for 

 immunity by one drastic course of treatment. 



The aim in using insecticides is to cover all parts with the 

 preparation. Dust the powders through a muslin bag or tin 

 perforated with tiny holes, and syringe liquids in such a way 

 that a fine white mist falls on the leaves like dew. Syringe from 

 below ; in fact this is even more important than from above, for 

 many pests hide on the under surfaces of the leaves, and are only 

 reached by liquid sprayed upwards ; keep going round the plant, 

 too, and syringe from all sides. Stir the liquid up now and again, 

 squirting some back into the pail occasionally to ensure uniformity 

 of composition by continual agitation of the liquor. 



