[ 507 ] 



AN OLD GARDEN IN IRELAND. 



INSECTICIDES. 



BEFORE selecting an insecticide it should always be remembered that some insects 

 teed by sucking the juices of plants, others by eating away the part of the plant 

 on which they are feeding, and that some insecticides are destructive to insect life 

 by poisoning the food, others by choking up the breathing pores of the insects, or 

 acting as a caustic to their skins. Those insects that have jaws and eat their food can be 

 poisoned, but those that live by suction cannot, for it is impossible to impregnate the juices 

 of a plant with a poison. Whatever insecticide be used will probably not kill the eggs (except 

 the very caustic ones), so that, particularly in the case of those insects that undergo their 

 transformations very rapidly, it is essential to use them two or three times, with an interval 

 of three or four days between each application, so as to make sure of killing the young as soon 

 as they are hatched. An ordinary syringe, as a rule, is not a very good instrument to apply 

 insecticides with, as they are not thrown on to the plants in such a finely-divided form as when 

 a spraying machine or a syringe with a spraying nozzle is used, and more of the insecticide is 

 wasted than when applied as a spray. There are various spraying appliances sold by those 

 who supply horticultural implements ; perhaps the most useful are the "knapsack" sprayers, 

 so called on account of their being carried on the back" like a knapsack. Thev hold about 

 3 gallons, but spraying nozzles are sold that can be attached to ordinary syringes or garden 

 engines. Whatever form is used, it is important that it should be capable of applying the 

 spray to the under sides as well as to the upper sides of the leaves, as it is there that red 

 spider, thrips, aphides, etc., most frequently congregate. 



In making up the following recipes, soft water should always be used ; if it is impossible 

 to procure this, a little soda should be added to the water before it is used. The following are 

 the insecticides which are generally found most useful, and instructions for making them 



