20 FUMIGATION FOR. THE CITRUS WHITE FLY. 



now raised from the water and after dripping ceases it is spread out to dry. The tank 

 is filled again and the tannin is added until the color is a reddish brown, and then 

 another tent may be dipped. 



In Florida fumigating tents become thoroughly wet nearly every 

 night they are in use, but even when untreated will not deteriorate 

 to any great extent during two or three months' use if thoroughly 

 drietl each day, and more especially before being finally rolled up for 

 storage during the seasons when not in use. Tents are conveniently 

 dried each day by simply leaving them on the last tree covered until 

 dried by the sun. The edges of the tent should be straightened out as 

 soon after sunrise as possible, and folds in the tent should be arranged 

 from time to time to facilitate drying. Such work, of course, shouhl 

 not ordinarily be considered as part of the work of the fumigating crew, 

 but can be readily attended to by some laborer employed at the grove. 

 It is considered by some fumigators that when tents are treated with 

 oil it is unsafe to leave the trees covered during bright sunlight, but 

 untreated tents can be safel}^ dried in this manner. Drying is prob- 

 ably hastened by pulling the tents partly off so as to make an open 

 space on one side to give circulation of air. Frequently it is a good 

 practice to pull a tent wholly or partially over two trees in order to 

 facilitate drying. When tents are dry, to prevent wetting by rain 

 and subsequent trouble in drying, they should be rolled up as com- 

 pactly as possible and arranged to shed water as well as practicable, 

 or they may be covered with waterproofed ducking or stored for the 

 time being in a dry place. 



Tents must be kept in repair during the fumigating season and 

 examined frequently during the daytime for holes which need patch- 

 ing. If tents are always pulled lengthwise of the strips of the cloth, 

 there is little danger of tearing, except when there is much dead wood 

 on the trees. One of the tents used by the agents of the Bureau of 

 Entomology during the winter of 1906-1907 was used to cover 

 upward of 100 trees without any injury of this Idnd. 



POLES AND UPRIGHTS. 



Poles and uprights are used, as shown in the illustrations (Pis. II, 

 III) , for raising the front edge of the fumigating tents when covering 

 a tree or pulling the tent from one tree to the next in the row. The 

 simple poles are as a rule used for tents not exceechng 48 feet in 

 diameter, and usually vary from 12 to 20 feet in length, according to 

 the height of the trees to be covered. In California straight-grained 

 Oregon pine 2 inches in diameter is generally preferred for poles not 

 exceeding 18 feet in length; for poles longer than 18 feet the diameter 

 should be 2^ inches. In the Gulf regions it is recommended that 

 seasoned cypress poles be used, as these are much lighter than the 

 available pine. Although onl}^ a single pair need be used with an 



