2l8 FUMIGATION METHODS 



The front of the fumigator can be opened as a double 

 door of a width equal to the shortest diameter of the 

 box. Unbleached sheeting so treated as to be gas- 

 tight is used as a cover. Careful tests with this fumi- 

 gator showed that it was practically gas-tight. 



Fumigation of orchard trees near Albany. A series 

 of tests were made by Dr. E. P. Felt, State Kntomol- 

 ogist, in the spring of 1900, with hydrocyanic acid gas 

 for the purpose of ascertaining its efficiency and prac- 

 ticability in the latitude of Albany, N. Y. A canvas 

 tent 6x6x8 feet with a fixed pyramidal hood 7 feet 

 high, as shown in Fig. 81, was constructed of eight- 

 ounce duck thoroughly oiled with boiled linseed oil. 

 The rectangular part of the tent was supported on a 

 light wooden frame, to reduce the variation in cubic 

 contents as much as practicable. The tent was lifted 

 with a thirty-foot pole and eight-foot gaff, and thus 

 dropped over the tree. The hood was kept extended 

 during the process of fumigation, as shown in the fig- 

 ure, illustrating also the manner of guying the pole 

 and tent. The tent and apparatus for handling it cost 

 about $38, but they could undoubtedly be made for less 

 when several were needed. A good pole and gaff from 

 near-by woods could be gotten at little expense. The 

 bottom of the tent was provided with what Dr. Felt 

 calls a " sod cloth." It consists of a flap six to eight 

 inches wide, which was covered with earth to prevent 

 the escape of the gas. An uncovered space was always 

 left on the windward side for the insertion of the 

 chemicals. The trees in these tests were exposed to 

 the gas for 35 minutes. After fumigation the guy- 

 lines were released, the sod cloth uncovered, and the 



