14 FUMIGATION FOR THE CITRUS WHITE FLY. 
the practice of some fumigators who, as has been stated, increase the 
dosage when the tents and foliage are wet with dew. It seems that 
the difficulty in handling wet tents is the only consideration for 
winch it is necessary to cease work on foggy nights, everything else 
being favorable. 
SIZE OF TREES AND REGULARITY OF SETTING. 
While it is true that it is possible to place a fumigating tent over 
any citrus tree regardless of size, the author strongly recommends 
that orange growers make a practice of pruning large seedling trees 
so that they will not exceed 28 or 30 feet in extreme height. Such 
pruning will greatly reduce the cost of labor in fumigating and will 
be of considerable advantage from the standpoint of picking the 
fruit. It is probable that the now generally recognized all-around 
advantage of low-pruned fruit trees applies squally well to citrus as 
to other kinds of fruits. Another consideration of importance is 
the regularity in the setting of orange groves and the proper spacing 
of trees. In Florida various factors have resulted in many groves 
being too crowded or too irregularly set to permit of the easy handling 
of fumigating tents. While it is well to bear these things in mind 
to the end that all Florida groves may gradually be adapted to 
reduce the labor and expense of fumigation, }^et even under present 
conditions it is exceedingly rare that fumigation is rendered abso- 
lutely impracticable by the size of trees or the irregularity of their 
setting. 
EQUIPMENT. 
TENTS. 
Styles of fumigating tents. — Two styles of tents are now in use for 
orchard f umigation, the bell or hoop tent (PL I.) and the sheet tent. 
The first is bell-shaped and held open at the mouth by a hoop of J -inch 
gas pipe. Tents of this style are preferable for use only when the 
trees in a grove are uniformly less than 12 feet in extreme height. 
Sheet tents are made in the form of flat octagons and, being adapt- 
able for trees of all sizes, are in California used almost exclusively. 
Plate I, figure 3, shows a tree which is 14 feet in extreme height and 
14 feet in extreme expanse, covered by a hoop or bell tent. When the 
tent is in position covering the tree the measurements are: Height, 
13 feet, and diameter, 12 feet. Hoop tents are not always easily 
placed in position over trees of this size, and it is believed that ordi- 
narily a sheet tent is more desirable for trees of all sizes. A third 
style of tent which will be found useful in fumigating small trees is 
the box tent in the form of a rectangular prism. This will probably 
prove advantageous for trees 5 feet or less in height. The light 
wooden framework supporting the cloth cover gives a form to the 
