590 Keport of Entomologists of the 



Experiments with Rkmediks. 



A large number of washes have been recommended as remedies 

 for scale insects. Before the experiments were undertaken, how- 

 ever, we wrote to Mr. L. O. Howard for his opinion regard- 

 ing a wash which would be effective against the phim scale. 

 Mr, Howard replied strongly in favor of kerosene emulsion. In 

 a letter to the Director of the station dated December 14, 

 1894, he says : "The only absolutely effective wash so far found, 

 viz., strong solution of whale oil or fish oil soap, is too expensive for 

 application in a large orchard. The only substance which could 

 rival the kerosene emulsion as used against your plum Lecanium 

 would be one of the resin washes, but the weather in central New 

 York in the winter time is too rainy to allow us to expect good 

 resuhs from this wash," It will be remembered that this scale, in 

 tommon with other scale insects, obtains its food by sucking the sap 

 from beneath the bark, hence an insecticide which would prove 

 effectual when applied on the trees must be one which kills by con- 

 tact. Kerosene emulsion is one of this class. The experiments 

 ^vere conducted in the orchards of T. Smith & Sons and Maxwell 

 Brothers of Geneva, whose courtesy we wish to acknowledge, and to 

 also express our thamks to Mr. C. K. Scoon of Geneva and Mr. 

 James Wright of Hector for their kind assistance. 



Plan of the ExperhnenU. — The experiments were planned with a 

 view to determining the relative merit of different strengths of kero- 

 sene, emulsion when applied during the winter, when the young 

 scales are hibernating on the trees, when applied in the spring, when 

 he young scales are growing rapidly, and when applied upon the 

 newly hatched scales. The emulsion was made according to the 

 formula usually given. In Bulletin 86 of this station, page 113, 

 directions for making kerosene emulsion are given, as follows : " This 

 is made by dissolving one-half pound of either common soap or 

 whale oil soap in one gallon of soft water. Heat the mixture and 

 when boiling hot remove it from near the fire and add it to two gal- 

 lons of kerosene. The whole is now thoroughly mixed by pumping 

 continuously through a small force pump for from five to ten minu- 

 tes. Mix until the ingredients form a creamy mass that becomes thick 

 when cool and from which the oil does not separate." In all of these 

 experiments the emulsion was sprayed upon the trees, great care being 

 taken to thoroughly drench the trees from the tops to the ground. 



