APPENDIX. 
TABLE OF DOSAGE FOR THE CITRUS WHITE FLY. 
The table of dosage herein given is based upon the author's experi- 
ments conducted in January and February, 1907. The mathe- 
matical calculations are tabulated and explained in the body of this 
bulletin. The most important object of fumigation experiments 
against the white fly has been the development of methods for the 
practical utilization of the fumigation process in Florida and the 
gaining of a knowledge concerning the dosage requirements. The 
former subject has already been disposed of through the methods 
herein described. The investigations concerning the latter subject 
have resulted in placing fumigation for the white fly on a basis 
whereby the process may be used against this insect with greater 
economy, thoroughness, and certainty of results than at present it 
can be used against any other species. Incidentally it should be 
remarked that the dosage requirements for the white fly are greater 
than for the Florida red scale and perhaps greater also than for 
the purple scale. It is beyond the scope of these investigations to 
determine the possibility of reducing the dosage below the white fly 
standard without interfering with its efficiency against these other 
pests. It is sufficient to know in most cases that the white fly dosage 
is equal to the actual requirements for the pests of secondary impor- 
tance. The dosage table here presented does not necessarily repre- 
sent the exact amounts for greatest utility in the case of the different 
sizes of trees. The extensive tests of the dosage table during the 
past winter, when, as has been stated, nearly 4.000 trees were fumi- 
gated under the direction of the agents of the Bureau of Entomology, 
show the doses recommended to be very close 1 to the aecessary 
amounts with tents of equal tightness with those used in the original 
experiments. The dosage should never be decreased when effective 
work against the white fly is desired, hut under certain conditions it 
may be increased from 10 to 25 per cent with advantage. 
If there i> a slight breeze of sufficient strength to make the advisa- 
bility of fumigating questionable, an increase in dosage of 10 per 
cent or more may allow the work to proceed without interfering with 
the efficiency; hut with ordinary tents of 8-ounce duck such increases 
do not offset the effects of strong or gusty breezes, which sway the 
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