8 BULLETIN 645, U. S. DEPARTMENT OF AGRICULTURE. | 7 
cally the same treatment as regards cultivation and _ fertilization. 
The fruit in the sprayed and unsprayed blocks grew on trees about 
30 feet apart, or in adjoining rows, and was picked and packed 
on the same day. The carload of sprayed -fruit shipped 87.4 per 
cent first and second and 12.6 per cent third and fourth grades; 
the unsprayed carload shipped no first, 3.8 per cent second, and 96.6 
per cent third and fourth grades. A more striking example of what 
a maximum infestation of rust mites will do and the benefits derived 
from spraying can scarcely be conceived. The carload of fruit left 
unsprayed after June shipped 80.3 per cent first and second and 19.6 
per cent third and fourth grades, thus indicating that if rust mites 
are controlled thoroughly until the ist of July on grapefruit little 
damage will result. In other groves russeting has been observed in 
January and February. | 
Grove 4.—In this grapefruit grove, 1 mile distant from grove 38, 
sprayed and unsprayed fruit was grown during 1914 in adjoining 
rows. The fruit from the sprayed trees shipped 18.8, 58.1, 15.1, and 
7.9 per cent, respectively, in the four grades known as “ fancy,” 
“bright,” “russet,”’ and “plain.” The fruits from the unsprayed 
trees shipped 6.6, 48.6, 49.7 and 6 per cent, respectively, in the same 
four grades. The percentage of second grade, or “bright,” fruit 
from the unsprayed trees is much greater than from unsprayed trees 
of grove 38, since the rust mites did not do so much damage in this 
grove. It will be noticed that 15.1 per cent of the fruit from sprayed 
trees was russeted, whereas 49.7 per cent was russeted on the un- 
sprayed trees. In grove 4 the poorer results were due to the inefii- 
ciency of the spray solution. 
The foregoing data, under the general head of grades of fruit, 
should convince any grower that it is possible to raise the grade 
‘of fruit by killing pests so that the fruit will grade at least 35 per 
cent first, 50 per cent second, and 15 per cent third, instead of the 
present average for the State, which is 13 per cent first, 41 per cent 
second, and 46 per cent third. Fruit usually will grow to a remark- 
able state of perfection on healthy trees if only the insects and mites 
are controlled. One grove, the fruit of which was packed by an asso- 
ciation noted for its high-class work, produced 90 per cent “ Blue,” 
or A No. 1 grade. The writer has seen 120,000 boxes of grapefruit 
from sprayed trees that graded 60 per cent first and 25 per cent 
second. 
REDUCTION IN SIZE CAUSED BY INSECTS. 
Insects and mites not only lower the grades of the fruit by the 
blemishes they cause, but reduce the size to a considerable extent. 
In raising the grades of the fruit by spraying, large benefits are 
obtained in preventing the pests from reducing the size. In com- 
mercial grading it is very difficult to show the difference in size of 
=| 
, 
