144 Forty-third Report on the State Museum. [48] 



are liable to suffer from tlieir injuries should know how they may 

 best be destroyed. Although serious pests, they are not beyond con- 

 trol if the proper remedies are resorted to. 



When scale-insects are discovered infesting a few trees in an 

 orchard, or are confined to a quite limited locality, the trees contain- 

 ing them should be cut down and burned at once, as the best way to 

 arrest the spread of the evil. 



The species that attack only the trunks and larger branches of 

 shade and other trees, may often be destroyed by scrubbing with a 

 stiff brush, wet with strong soap-suds. 



When the foliage is infested, a garden syringe or a force-pump 

 must be employed for spraying the insecticide used. The two 

 best insecticides for the purpose are soap and kerosene. The 

 first has been thoroughly tested in many experiments made by, 

 or under the direction of, Professor Comstock, and is strongly 

 recommended by him, to be used in the following manner: In a 

 gallon of hot water one-fourth of a pound of whale-oil soap is 

 dissolved, and its application is made at a temperature of about 100° 

 Fahr. It should be repeated after an interval of a few days. As 

 the result of other experiments subsequently made, it is stated that 

 one pound of concentrated lye to one gallon of water, will effectually 

 destroy all scale insects, drying up the scales and the eggs beneath 

 them, and killing the young insects if hatched. It is asserted, how- 

 ever, by Professor Riley, that whale-oil soap and lye both fail to kill 

 the eggs of scale-insects, and he therefore urges the iise of kerosene 

 as greatly superior to them, and decidedly preferable to any other 

 known substance for the eradication of these pests. 



The most simple way to apply the kerosene is to mix it with water, 

 for undiluted it is destructive to many kinds of vegetation, while not 

 affecting others. As it separates quite quickly from the water — in less 

 than a half-minute — it requires to be kept in constant agitation, 

 which may be done by discharging the syringe or pump several times 

 into the vessel before applying the liquid to the trees, and continuing 

 to alternate the discharge from the tree to the vessel. 



The Kerosene Emulsion. — But, by far, the best way in which to use, 

 with perfect safety, kerosene for insecticidal purposes, is to make an 

 emulsion of it with some substance that will bring it into the desii'ed 

 condition. Milk was first employed, but subsequently it was found 

 that soap was preferable, from several considerations, such as cost, con- 

 venience, permanency, etc. The method of preparing this emulsion has 

 been repeatedly given in entomological publications and agricultural 



