FUMIGATION OF CITRUS TREES. 25 



usually an hour or thereabouts, the tent is removed to the next tree 

 and the process repeated. The work is carried on at night. 



Let it be supposed that a man owning an orchard of several acres 

 has made arrangements to have this fumigated. Before entering on 

 the actual work certain preliminaries are attended to. The fumigator 

 prefers and usually requires that the orchard shall have been culti- 

 vated recently so that the ground shall be clean and smooth. This 

 condition of the soil is not only an advantage to the fumigator but to 

 the grower as. well, for in loose level soil the tents will lie closer to the 

 ground and thus allow less escape of gas underneath than would be 

 possible on weedy or roughly furrowed land. The moving of the 

 chemical cart or wagon is also more difficult on the rougher ground. 



An outfit usually consists of about 30 tents. Before placing the 

 outfit in the field the fumigator makes a survey of the orchard in 

 order to determine in what manner the tents can be used to best 

 advantage. This depends on such considerations as the arrangement 

 of the trees, the length of the rows in different directions, slope of the 

 soil, whether irrigation furrows are present, location of water supply, 

 and similar factors. Having decided the direction in which the tents 

 shall be pulled, the wagon which has moved the outfit from the pre- 

 ceding field to the present one is driven along the first row to be 

 fumigated and a tent and generating pot dropped off at each tree. 

 The " commissary," or place where the supply of chemicals and water 

 is located, should preferably be near one end of the row of tents. 

 The location of the source of water will, of course, determine this 

 position. If no source is bordering the field, barrels should be pro- 

 vided for this purpose. The acid is usually furnished in large iron 

 drums. It is. convenient to remove the acid from the drums into 

 10-gallon glass carboys of the nature shown in figure 6. These car- 

 boys are easy to handle and two or three hold enough for a full 

 night's work. 



Immediately preceding the treatment the tent-pullers unfold the 

 tents and have them in position for covering the trees. This position 

 should be with one end facing the tree on the side away from the 

 direction in which they are to be moved. Covering the trees is 

 commenced at one end of the row. Two poles of the character 

 described on pages 20-21 are required, one for either side of the tree. 

 If rings are in the tents the ends of the poles are attached to the 

 rings. However, it is very much easier and more satisfactory not 

 to use rings on tents manipulated by poles, but to double-lap the 

 edge of the tent over the end of the pole and attach it by a half hitch 

 of the pulling rope (Plate III, fig. 1). This is quickly done, does 

 not subject the tent to undue wear, and prevents detaching, as 

 sometimes occurs with rings, but the greatest advantage is that the 

 distance between the poles can be gauged in accordance with the 



