6 BULLETIN 616, U. S. DEPARTMENT OF AGRICULTURE. 
boxes, of navel oranges were shipped. The loss suffered from grade 
reduction due to thrips by the Lindsay district alone, and in a season 
of comparatively light infestation, was therefore about as follows: 
Forty-three per cent, or 255,742 boxes, reduced to second grade at a 
loss of 37 cents per box, making $94,624.54; and 23 per cent reduced 
to third grade at a loss of 65 cents per box, making an additional 
$88,914.80, or a total loss of $183,539.34. 
EXTENT OF DAMAGE IN SOUTHERN CALIFORNIA. 
It is calculated that from 20 to 40 per cent of the 1910 orange crop 
of Riverside County was sufficiently marked to keep it out of first 
grade. The injury was most severe in groves in the hills to the south 
and east of Riverside and in the vicinity of Highgrove, where con- 
ditions are similar to those along the foothills in the San Joaquin 
Valley. In this section about 55 per cent of the crop was lowered in 
grade because of thrips marking. Of the 1911 crop in the same 
groves, however, only 16.9 per cent was marked sufficiently to throw 
it out of the first grade. 
At Redlands the injury was somewhat less severe than at River- 
side. Only from 2 to 5 per cent of the first-grade fruit running in 
the packing houses was marked, and that slightly, while from 50 to 
60 per cent of the second-grade fruit was more seriously damaged. 
The writer was informed that fruit from some of the groves was 
injured more severely than that then passing, and when such fruit 
was being packed an additional or third grade was added to accom- 
modate the thrips-marked oranges. 
In the Pomona- Claremont-Upland section damage by the citrus 
thrips was much less severe than at Riverside and Redlands. The 
grades of fruit then running were " fancy " and " choice," and it was 
estimated that about 10 per cent of the first-grade oranges had traces 
of marking and about an equal percentage of the second, or choice, 
fruit was more conspicuously marked. The most severe marking oc- 
curred at Claremont, which is nearer the hills, a little warmer, and 
produces very vigorous trees. First-grade fruit was scarred about 
equal to that at Pomona, but a third grade was run at Claremont, 
about 25 per cent of which had been reduced because of thrips 
scabbing. 
The injury decreases toward the coast, so that at Whittier only 
about 10 per cent of the entire crop was scabbed. About 2 per cent 
of the first and 5 per cent of the second-grade fruit had been slightly 
marked. Less than 1 per cent of the marked fruit of second grade 
would be placed in that grade because of thrips injury alone. Lemons 
were blemished about as much as oranges. At Pasadena 90 per cent 
of the 2,000 oranges examined in the field was entirely free from 
