REPORT ON THE EFFECTS OF COLD UPON THE SCALE INSECTS OF 
THE ORANGE IN FLORIDA. 
By JOSEPH VOYLE. 
GAINESVILLE, FLA., December 10, 1883. 
Str: I have the honor to present the following report of experiments 
made with cold temperatures on scale insects injurious to orange trees. 
These experiments were made for the purpose of obtaining some infor- 
mation as to the extent of relief given by frost to infested trees, there 
being a very general belief that any damages to the tree by frost are 
fully compensated for by the destruction of injurious insects. Several 
successive winters with cold of such severity as to, in some cases, seri- 
ously damage orange trees, having been followed by heavy swarms of 
destructive scale insects, gave reason for doubting the truth of the 
accepted theory. During the past winter, 1882-’83, by some special 
observations, positive evidence was obtained that often very little dam- 
age was done to scale insects by cold that killed the tender orange 
shoots. On the morning of December 16, 1882, the thermometer was 
reported at various figures, from 19° to 25° F. My own lowest read- 
ing was 25°. On this morning I cut orange branches incrusted with 
seale insects and found young migratory larvee of Mytilaspis running 
about quite lively. 
By your direction I entered upon a series of experiments that should 
as nearly as practicable solve the question of “‘ What temperature is fatal 
to the larvee and to the eggs of these scale insects?” The laboratory 
of the East Florida Seminary, with its apparatus, was placed at my 
service for this work, but fire destroyed the building and contents be- 
fore the work was begun. It was therefore necessary to devise some 
inexpensive means of accomplishing the work. The final result of ex- 
periments for this purpose was a freezer composed of three tin cylinders 
of 10 inches, 6 inches, and 2 inches diameter, respectively. The 6 inch 
was placed within the 10-inch, and by means of a collar both were 
fastened together and the space between them filled with dry feathers; 
another collar then fitted on, and all soldered tight. A suitable collar 
being fitted to both ends of the 2-inch cylinder (which was only 10 
inches in length, the others being 14), it was placed within the 6-inch, 
equidistant from the ends, and soldered tight, thus leaving room for a 
head 2 inches thick and 6 inches diameter at each end, the heads being. 
packed with dry feathers. Thus was obtained a central chamber within 
an empty annular chamber,: surrounded by another annular chamber 
filled with a good non-conductor; the central chamber for the speci- 
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