60 FUMIGATION FOR THE CITRUS WHITE FLY. 
had increased sufficiently to cause blackening of the foliage and 
fruit before repeating the treatment. 
The extent of the damage due to the white fly is difficult to estimate. 
After supplementing his personal observation with direct information 
and estimates on this point from more than 50 orange growers who 
have had experience with the pest, the author would consider 50 per 
cent a conservative estimate of the average annual loss in white-fly- 
infested groves. 
The consensus of opinion of the orange growers referred to is to 
the effect that the reduction in the size of the crop alone amounts to 
50 per cent or more, leaving out of consideration the loss through the 
checking of the growth of trees, the retardation of ripening, the 
expense of washing the fruit, and the impairment of its shipping 
quality and flavor. In many cases the damage from the fly renders 
citrus fruit growing unprofitable, although such losses are usually 
unnecessary if proper care be given to cultivation and fertilization. 
The beneficial effect of the fungous diseases of the white fly and the 
economy of fumigation where the diseases are prevalent will be 
discussed under another heading. The data at hand concerning the 
cost of fumigation indicate that in most cases the expense would be 
sustained by the increase in production if the losses of the white fly 
were only 10 per cent, instead of the 50 or more as generally estimated. 
Losses from scale insects. — In calculating the benefits derived from 
fumigation, the effect of the treatment on other citrus pests is an 
important consideration. Fortunately the high average of humidity 
in the citrus-growing sections of the Gulf States results in the partial 
control of scale-insect pests which would otherwise make direct 
remedial measures necessary for profitable crops. The thoroughness 
of this natural control varies greatly in different groves according to 
local conditions. Fruit infested with the purple or the long scale is far 
less valuable, as a rule, than is clean fruit. If such fruit is cleaned 
before packing, the cost is usually from 10 to 15 cents per box. In 
the markets scaly fruit in rare instances brings as much as fruit free 
from scale, but ordinarily it brings from 25 to 75 cents less per box, 
even after being cleaned by hand. If not cleaned it may fail to find 
a market at any price. When handled by orange buyers and sold 
upon the tree, even a small percentage of scaly fruit frequently 
results in a considerable loss in selling value of the entire crop. 
Direct information has been obtained from many orange growers 
and shippers concerning the effect of scales upon the value of fruit. 
The damage reported ranges from none at all to 26 per cent of the 
total value of the crop. Ordinarily from 5 to 1 5 per cent of the crops 
of oranges and grapefruit are sold as of an inferior grade owing to 
infestation 1>\ the long and purple scales. One grower in Lee County 
reported that last season (fruit shipped in December, 1906) he suffered 
a loss of si ,500 on a crop of 1,000 boxes of oranges and 2,000 boxes of 
