2 9 THE HOP APHIS IX THE PaCIEIC REGION. 



ADVANTAGES OF FUOUB PASTE OVER WHALE-OIL SOAP AS A SPREADER 



FOB CONTACT INSECTICIDES. 



Flour paste costs S I Qts per 100 gallons of spray. Cheap flour 

 is always available, and the paste has no odor. Whale-oil soap costs 

 _ cents per 100 gallons of spray, is not always available, and has 

 a disagreeable odor. 



Both materials have to be heated before using. 



The neutrality of flour paste was proven by the fact that when 

 applied upon the foliage and blossoms of the hop. in proportions as 

 high as 12 gallons of paste to 100 gallons of spray, no injurious 

 effects resulted. When sprayed upon the hop burrs and delicate hop 

 cones, it did not prevent pollination or injure the appearance of the 

 scales. 



QUASSIA. 



Quassia is the extract from the wood of Picrsena txalsa. a tree 

 airing in Jamaica and containing the alkaloid quassin 'C ; _H._ ( 

 in the form of crystalline rectangular plates. Quassia chips contain 



no tannic acid. 



EFFECT OF QUASSIA ON* APHTPE- 



A solution of quassia containing the extract from 5.33 ounces of 

 quassia chips in 1 quart of water was diluted one-half and sprayed 

 on Hy on piune. It was found necessary to wash 



the waxy pulverulence from the insects before they could be wetted. 

 The leaves were tagged with the numbers of aphides present and the 

 twigs set into water in the laboratory. A check branch was sprayed 

 with pure water. That the strong quassia solutions have a decided 

 insecticidal value is shown by the following data: 



Aphides present before sprayinr I ". 140. 40: total. "_ 



Aphides present after spraying. 0. 30. 3. 1. 0. 25, 0. 0: total. 

 Pef cent killed I 



Quassia solution at the rate of 7 pounds of chip:* to 250 gallons of 

 water was applied to the aphides with the following result- 



Aphides present before spraying. 4S. 60. 30. 40. 73. 30. 200. 100. 63. 12- _ 

 Aphides present after spraying. 0. 0. 5. 0. 0. 0. 1. 2. 7. 9. 10: total. 34. 

 Per cent killed. 96. 



The aphides on sprayed leaves turned brown when dead. The 

 check leaves contained living insects only. 



