18 BULLETIN 645, U. S. DEPARTMENT OF AGRICULTURE. 



sell, according to Table 7 (grapefruit), for 41.7 cents more per box, 

 or an increase of $61,182. 



The total increase in value by raising the grade would be $509,955 

 for the entire crop of oranges and grapefruit. 



Elsewhere in this bulletin it has been shown that " russet " fruit is 

 of about one size, or about 12.5 per cent smaller than normal fruit. 

 If it is estimated that one-half of the crop is " russet " there would 

 be a reduction of 475.000 boxes, which, valued at $1, would produce 

 a loss of $475,000. This is extremely conservative. As a matter of 

 fact, 100,000 boxes of fruit in Florida are thrown away because the 

 fruit is too small ! 



In regard to the reduction in yield caused by the devitalization of 

 the trees, it is very conservative to estimate this at 10 per cent, or 

 760,000 boxes. In reality it is probably 20 to 25 per cent, and many 

 sprayed groves prove this to be true, but for this estimate it is placed 

 at 10 per cent. This amount of fruit is valued at $760,000. 



This would make a total of $1,744,955 as a minimum estimate for 

 the increase that could be expected from spraying the entire crop. 

 The cost of spraying groves producing 7,600,000 boxes would be not 

 more than 6 cents per box, or $456,000. This would be a net gain of 

 $1,288,955 in the value of the crop produced. This gain could be 

 divided in half and still a handsome profit would follow spraying. 



In addition to the direct profit, there is the satisfaction, which every 

 enthusiastic orange grower must feel, in maintaining healthy trees 

 and producing high-grade fruit. 



CONCLUSION. 



Of the total damage caused by insects and mites to citrus in 

 Florida, more than 95 per cent may be attributed to six species. 

 These, in the order of their destructiveness, are the citrus white fly, 

 the purple scale, the rust mite, the red scale, the cloudy-winged 

 white fly, and the red spider. 



Aside from the satisfaction of growing fine fruit and owning- 

 healthy trees, it is estimated from the data reported in this bulletin 

 that had the 1915-16 crop of oranges and grapefruit been sprayed 

 according to the schedule recommended, the growers of Florida 

 would have increased their net returns by $1,288,955. 



There is no reason why the standard percentage of fruit in the 

 higher grades can not be raised so that the percentage in the first, 

 second, and third grades will be 35, 50, and 15 instead of, as at pres- 

 ent, 13, 41, and 46. In one of several instances given, spraying in- 

 creased the amount of fruit in the first and second grades from 24.6 

 to 94.9 per cent, and reduced that in the third and fourth from 75.4 



