62 
FLORIDA STATE HORTICULTURAL SOCIETY. 
all of the eggs deposited by these 
adults may have time to hatch. It 
should be remembered that the pres¬ 
ence of adults is practically a positive 
indication of the presence of unhatched 
eggs. It is impracticable to attempt to 
destroy the egg stage by fumigation 
or, as a rule, by any other direct 
means. The scale-like stages, techni¬ 
cally kno'wn as the larval and pupal 
stages, are readily destroyed when the 
dosage is properly estimated. 
Ordinarily, it would be undesirable 
to continue fumigation after the adults 
begin to emerge in considerable num¬ 
bers in the spring. This time, of 
course, varies according to locality and 
weather conditions, but in general is 
between the middle of February and 
the first of March. 
For some not well understood rea¬ 
son, fumigation with hydrocyanic acid 
gas in bright sunlight is liable to cause 
injury to the foliage even though in 
the absence of bright sunlight the same 
dosage might give entirely satisfactory 
results. On cloudy days, it is safe to 
fumigate during the middle of the day, 
but on clear days the work should not 
be started until between four and five 
o’clock in the afternoon. Fumigation 
should not be attempted in a strong 
breeze particularly if the tents have 
not been made gas tight or nearly so 
by one of the treatments which will 
be referred to hereafter. The presence 
of moisture on the leaves in the form 
of dew does not seem to have any del¬ 
eterious effect upon the foliage al¬ 
though in California it is considered 
necessary to increase the dosage in 
such cases to ensure effectiveness of 
work against scale insects. The tents 
are more difficult to handle when wet, 
and it has not yet been determined 
whether, everything considered, it is 
desirable to continue to fumigate when 
the foliage has become wet with a 
heavy dew. 
EQUIPMENT. 
Many different styles of fumigating 
outfits have been employed in orchard 
fumigation in California since the first 
discovery of the process. Ordinarily 
a person unfamiliar with the practices 
of recent years, pictures to himself 
some clumsy process of shifting bell or 
dome shaped tents from tree to tree 
by means of huge derricks, mounted 
on wheels and provided with gafts and 
an intricate system of ropes and pul¬ 
leys. Such methods, however, have 
long since become a thing of the past 
and their use is remembered only as in¬ 
teresting incidents in the early history 
of the fumigating process. 
Practically all modern tents for fum¬ 
igating purposes are made in the form 
of regular flat octagons, and are gen¬ 
erally made of six-ounce drill and eight- 
ounce duck. A tent of this pattern is. call¬ 
ed a “sheet tent” and its size is stated 
according to its diameter. In general 
a sheet tent is large enough for a tree 
that measures not over two-fifths of 
the given size. For trees up to 14 feet 
in height, bell or dome shaped tents, 
held open at the bottom by means 
of a gas pipe hoop are sometimes used. 
With small trees of uniform- size, they 
are easy to handle and they require 
less material in their construction, but 
they are not as adaptable for general 
use as are sheet tents, and hence are 
not as extensively used. 
It is the general custom in Califor- 
