10 



Remedial Measures. 



To control these insects, persistent work is required. Where they 

 have reached the flying stage it is necessary to fill the air around the 

 treated plant with the spray mist, so that the insects, even if they 

 leave the plants and fly, will encounter the insecticide and be killed 

 by it. As they feed like plant lice, they are equally immune against 

 arsenical preparations, and must be reached by contact poisons. To- 

 bacco is not nearly so satisfactory as the soap mixtures, and of the soaps 

 those carrying kerosene or naphtha are best. Instead of soap mixtures, 

 the kerosene emulsion or one of the soluble preparations of kerosene 

 or crude oil may be employed, and all these are effective in proportion 

 to the thoroughness with Which the application is made. Here, also, 

 the element of time is of importance. If the applications are made 

 before the insects are winged, they will be easily hit upon the plant 

 and most of those touched will be killed. If the application is jmade 

 afterward, many will get away; or, even if they are hit by the spray 

 when upon the plant, it does not reach the spiracles. Which are pro- 

 tected by the wing covers. It is really better, therefore, to disturb 

 the insects so as to cause them to fly, the spray being directed in such 

 a way as to hit them in the air. As to the strength of the mixtures, 

 that may be as recommended for plant lice. 



SCALE INSECTS. 



Scale insects are among the worst pests of the garden, and some are 

 seriously troublesome on shade trees as well. Among the latter, the 

 soft maples are especial sufferers from the cottony maple scale; the 

 hard maples suffer to a less extent from a Pseudococcus, and the tulip 

 tree is attacked by a soft scale. Nut trees are often infested by the 

 oyster-shell bark louse, which is also quite common on poplar and 

 willow, while only occasionally troublesome on elm and maple. In the 

 garden, scale insects are even more plentiful, almost all shrubs and 

 most of the ornamental plants suffering to some extent. The San 

 Jose or pernicious scale attacks almost everything except privet and 

 cherry ; the oyster-shell bark louse sometimes ruins lilacs, is common 

 on Cratcegus, Euonymous and many other shrubs, as well as on apple. 

 The scurfy scale is usually less abundant, but is sometimes common 

 enough on apple and pear. The rose scale attacks blackberry and 

 raspberry, and on roses sometimes causes considerable trouble. 



