I OS! OF EQUIPMENT. 57 
The cost of the sheet tents would be considerably reduced by the 
use of one or two widths of 6^-ounce drill, sewed around the margin 
as a skirt, as described under the subject of construction of fumigat- 
ing tents. The difference between the cost of tent materials in Cali- 
fornia and in eastern citrus-growing States, owing to the greater 
distance of the former from the factories, should result in a reduction 
i)i' from 2 to 5 per cent in the cost of an outfit ;it any point in the 
( rulf States. In Florida theseason for rumigal ing against t he white fly 
extends over from seven to ten weeks. During this time a fumigating 
tent, used between thirty-five and fifty days on an average of eight 
hours per day with forty-live 4 minute 4 exposures, would he used to 
cover between 280 and 400 trees. A tent large enough to cover the 
largest trees should ordinarily not cost over $110. It lias been 
stated thai the tents used in the author's experiments in January 
and February, 1007, have not deteriorated appreciably. With 
proper care tents should last several seasons, whether untreated 
or mildew-proofed. If such a tent as referred to above should he 
used for only three seasons, and be used to cover only between 280 
and 400 trees each season, the cost of the wear and tear of the tent 
would amount to only from 9 to 12 cents per tree. Even taking into 
consideration interest on the money invested, the cost per tree 
would not exceed 15 cents. This is fully twice the cost of a tent 
large enough to cover trees of average size. 
In many cases it would not be advisable for an orange grower to 
invest several hundred dollars in fumigating tents for his exclusive 
use, although many with extensive groves would doubtless prefer 
to do this. When possible individual ownership of an outfit is desir- 
able. In some citrus fruit growing countries where fumigation is 
practiced against scale insects several growers form a club and 
-hare the cost of the fumigating outfit, which is left at the disposal 
of each of the members in turn. Such a plan might be followed in 
many eases in Florida. It is especially to be recommended where 
several groves constitute a naturally isolated group, and cooperation 
lias all the advantages of individual ownership of a single isolated 
grove. A few citrus growers with a crop worth on an average $25,000 
would not he put to unreasonable expense in the joint ownership of 
an outfit costing SI, 200 or $1,500. The rapid growth of the idea of 
orange growers' associations in Florida during the past few months 
leads to the hope that a means is at hand for providing for systematic 
campaigns against citrus pests. In some cases associations for this 
purpose have already been organized. Fumigation by the contract 
system, as it is now done to a large extent in California, may also 
come into use in Florida. The plan which can he most strongly rec- 
ommended is for the work to he done by the various counties. Each 
