iTTER OF TRANSMITTAL. 
U. s. Department of Agriculture, 
Bureau of Entomology, 
Washington, J). C, June 11, 1908. 
Sir: I transmit herewith, for publication as Bulletin No. 76 of this 
Bureau, a reporl on fumigation for the while fly, as adapted to Florida 
conditions, by Dr. A.W. Morrill, special field agent. 
The investigation of the white fly problem in Florida is now in its 
second year, and the results gained of immediate practical importance 
are those which indicate host methods of control. Fumigation with 
hydrocyanic-acid gas during the short dormant period in winter, when 
there are no winged insects, seems to afford the greatest measure 4 of 
control orpossible extermination. Gas fumigation under the horticul- 
tural conditions obtaining in Florida orange groves and the peculiari- 
ties of climate presents rather a distinct problem. This bulletin gives 
the results of the fumigation experiments of two winters in Florida, 
and demonstrates the entire applicability of this method of control to 
the white fly. This investigation has been under the general direc- 
tion of Mr. C. L. Marlatt, Assistant Chief of this Bureau, with Doctor 
Morrill in field charge. The latter was aided during the winter of 
1906-7 by Mr. Stephen Strong, formerly horticultural commissioner 
of Los Angeles, Cal., and an experienced fumigator, and Mr. A. 0. 
Morgan, and during the winter of 1907-8 by Messrs. E. A. Back, 
W. W. Yothers, and R. S. Woglum. 
The white fly is the big insect problem of Florida and other citrus 
districts on the Gulf coast, and the information given in this bulletin 
will be of immediate practical value to all citrus growers of the region 
indicated. 
Respectfully, L. O. Howard, 
Entomologist and Chief of Bureau. 
Hon. JAMES Wilson, 
Secretary <>J\ [gricu/ture. 
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