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 tliis insect with greater 

 economy, thorouglmess, 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 to the necessary 

 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, but under certain conditions it 

 may be increased from 10 to 25 per cent with advantage. 



If there is 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 ; but 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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