270 



at the time the most feasible, we find that it is entirely impracticable 

 and at once proceed to accomplish the desired result by some other 

 means until a method is found that proves to be a complete success. 

 The complete failure of the first method, while it may be very dis- 

 couraging, ijuts us on our metal to discover something that will 

 prove effectual ; whereas if a partial success had been secured in the 

 first instance, we would in all probability have been content to rest on 

 our laurels and have adopted that method as the best one available ; at 

 least such has been my experience during the past season. 



Early in the spring a letter was received from Col. J. J. Eoss, an ex- 

 tensive fruit grower residing in the vicinity of Seaford, Delaware, stat- 

 ing that the peach trees in his young orchard were being destroyed by 

 the Aphis, and requesting me to visit his place and see what could be 

 done to destroy the insects. Upon arriving there I found a large num- 

 ber of the trees literally covered with the species now known as Aphis 

 versicce-niger, the name and description having since been published 

 by Dr. Erwin F. Smith, in Entomologica Americana. These Aphids 

 may be found in an infested orchard at all seasons of the year, located 

 either upon the roots or upon the limbs and twigs of the trees. 



The trees were from 4 to 5 feet in height and the leaves upon many of 

 them were already withered, and in some instances entirely destroyed. 

 I began spraying the trees in the afternoon with kerosene emulsion in 

 proportion of 1 part to 15 parts of water, using the Nixon Little Giant 

 spraying machine and Kixon nozzle. An examination of the sprayed 

 trees the next morning gave such assurance of the effectiveness of the 

 treatment that Colonel Eoss immediately ordered one of the Lockport 

 machines by telegraph. After showing method of preparing the emul- 

 sion, I returned to the Experiment Station to attend to other work. 

 Subsequent sprayings under Colonel Eoss's direction he informed me 

 did not succeed in destroying the Aphids. Whether the failure was 

 due to faulty preparation of the emulsion or the lack of thoroughness 

 in the application, I am unable to say. 



Upon hearing of this failure, I at once sprayed with the emulsion 

 several badly infested trees in an orchard near Dover, and upon exam- 

 ining twigs from the sprayed trees about 20 hours after treatment, 

 by actual count I found that 80 per cent, of the Aphids had been de- 

 stroyed by a single treatment. Upon my recommendation, Dr. Hugh 

 Martin used the kerosene emulsion upon infested trees in his orchard 

 near Bridgeville and one application resulted in entirely freeing the 

 trees from the insects. 



I advised several other parties to use a decoction of tobacco and water. 

 Mr. E. G. Packard, of Dover, Delaware, took 5 pounds of tobacco stems 

 and steeped them in 3 gallons of water for 3 hours. After straining 

 the decoction, he added sufBcient water to make 7 gallons. This 

 amount was sufficient to spray two hundred two-years-old peach trees 

 that were badly infested with the Aphids. One treatment proved ef- 

 fectual. 



