INJURIOUS INSECTS. 113 



powder and dusted on bj" means of bellows prepared for that pur- 

 pose, or it may be used in solution in water, which is believed to 

 be the most economical and efficient method. The bulk of the 

 powder is dissolved in the water, to which it at once imparts its 

 insecticide principle. No stirring is necessary, but it should be 

 applied in a very fine spra}' ; the finer the more economical is its 

 use and the greater the chance of its reaching all the insects. 

 This solution should be used when first made, for it gradually loses 

 its power when it is allowed to stand. 



Pj'rethrum is also an excellent insecticide for the cabbage but- 

 terfly, all kinds of plant lice, flea beetles, thrips on rose bushes 

 and grape vines, and many other insects, but it is liable to be 

 adulterated and one should be very careful to purchase only that 

 which is pure. This insecticide has the decided advantage of 

 being harmless to man and the domestic animals, and maybe used 

 with impunity where Paris green or London purple would require 

 to be used with great caution. Experiments have shown that half 

 an ounce stirred in two gallons of water was sufficiently strong to 

 kill any ordinary naked caterpillars when showered on them, but 

 was not strong enough to kill the most hardy or such as are pro- 

 tected by a dense, hairy covering. 



The rose beetle is a ver}" common pest and feeds on so many 

 different plants as to make it much more troublesome than if it 

 confined its attacks to one plant alone. If they are infesting a 

 shrub or tree upon which it is safe to use Paris green, this will 

 prove a most effectual remedy, but if for any reason it is not safe 

 to use a poisonous insecticide, pyrethrum may be used. 



To destroy currant worms and slugs on rose bushes and pear 

 trees and, in fact, larvae of any of the saw-flies, dissolve one ounce 

 of powdered hellebore in a little warm water and then dilute it 

 with two gallons of water and spray it onto the bushes. Paris 

 green could be used in spray on our ornamental and shade trees 

 for any saw-fly larvae which might be injuring them. 



Another very valuable insecticide is the kerosene oil emulsion. 

 This is made of two parts of kerosene oil and one part of milk, 

 either sweet or sour, but preferably sour. Mix these in a pail or 

 tub, by continuously pumping with a force pump, through the 

 spray nozzle, back into the pail. After a short time, the liquids 

 unite and form a creamy emulsion and finally a white and glisten- 

 ing butter perfectly' homogeneous in texture and stable in char- 



