22 WHITE FLIES INJURIOUS TO CITRUS IN FLORIDA. 
be found in the market. When trees are supplied with as much 
fertilizer as they can use to advantage the white fly does not ordi- 
narily affect the flavor of the fruit to such a noticeable extent as is 
commonly believed. It is suspected that a well-grounded prejudice 
against the white fly rather than a discriminating taste is responsible 
for a large part of the supposed effect on the flavor of the fruit in 
infested groves. 
Increased injury from scale insects and from 'plant diseases. — The 
number of culls is in some cases very much increased by diseases and 
insect pests which thrive after the trees have been weakened by the 
white fly. There are no data available showing the usual increase in 
percentage of fruit injured by scales and by diseases of the trees as 
a result of white-fly infestation, but this is a consequence observed 
by many citrus growers and is properly considered a factor of white-fly 
injury. As such it is conservatively estimated to vary from 1 to 5 
per cent in groves thoroughly infested, although an instance of a 
valuable crop being completely ruined by secondary scale attack has 
come under the authors' observation. 
Market value. — Imperfections in fruit rind due to diseases and 
insect pests as followers of the white fly and to failure of fruit rind to 
color up normally, in addition to the direct effect on the size of the 
marketable crop as heretofore discussed, usually lower the average 
grade even after the fruit is cleaned by the most approved methods. 
A few growers claim that after being cleaned their oranges and tanger- 
ines bring as good prices as any, and leaving out of consideration 
instances where it is claimed that most or all of the fruit is rendered 
absolutely unsalable under any conditions, we may conservatively 
estimate the depreciation in market value to range from none at all 
to 10 per cent. 
Sooty-mold-blackened oranges shipped without cleaning have a 
market value . ordinarily from 25 to 50 cents less per box than the 
same fruit would have cleaned. 1 Certain Florida brands of oranges 
well advertised, carefully graded, and packed, would fail to bring within 
a dollar a box of their average value if they appeared on the market 
blackened by sooty mold. 
Losses to growers estimated on basis of prices paid by orange buyers. — 
The authors are indebted to Mr. E. H. Walker, of Orlando, for the 
information that during the season of 1907-8 orange buyers in Florida 
paid from $0.75 to $1.45 for oranges free from white-fly effects, and 
from $0.50 to $1 per box for fruit blackened by white fly; during 
the season of 1908-9 the price paid for clean fruit varied from $0.60 
to $1 per box, and from $0.50 to $0.75 for fruit blackened by sooty 
mold. The loss to the growers is not entirely represented by these 
1 Statement based on information from Mr. E. H. Walker, Orlando, Fla. 
