62 
FUMIGATION FOB THE CITRUS WHITE FLY. 
that the owners' fruit-shipping records show annual losses from this 
source amounting to between 15 and 20 cents per tree. Live scales 
in all stages, particularly the egg and adult, were very abundant 
before fumigating, but up to the 1st of June careful examinations of 
thousands of leaves, twigs, and green fruits by Mr. Yothers and the 
writer have not led to the finding of a single living specimen of this 
>|>ecies in the section of the grove which was the most heavily 
infested. At this season of the year there is usually no difficulty in 
finding more or less abundant specimens of the spring brood of this 
insect even where it was so scarce the previous season as to occasion 
no appreciable damage to the crop. 
COST OF FUMIGATION COMPARED WITH SPRAYING. 
In Florida the average cost of spraying is between 2\ and 3 cents 
per gallon of spray applied. When spraying is done with such effi- 
Fig. 11.— Purple scale (Lepidosaphes beekii), showing different stages of female: o. Newly hatched larva: 
b, same with first waxy secretion; c to/, different stages of growth: a. mature scale; //. same inverted, 
showing eggs: i and ./'.half-grown and full-grown female insects removed from scale. All much enlarged 
(after Marlatt). 
ciency that blackening of the foliage and fruit by the sooty mold is pre- 
vented, at least three applications per year, and usually four or more. 
are necessary. The mechanical difficulties of spraying with as much 
effectiveness as tins are so great as to make the results with ordinary 
practices far inferior to those from fumigating. In fact the results 
with sprays have with few exceptions been unsatisfactory in con- 
trolling the white fly or preventing the blackening of the fruit and 
foliage. In many cases this is largely a result of the character of the 
labor which it is necessary to employ for such work. For the pur- 
pose* of comparing spraying with fumigating in regard to cost, it may 
be considered that three applications of sprays per year will control 
the white fly in a satisfactory manner, although in actual practice 
this is rarely accomplished unless drought or fungous diseases offer 
material aid 
