8 BULLETIN 645, t'. S. DEPARTMENT OE AGRICULTURE. 



callv 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 clay. 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, 3.3 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 1st 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 3, 

 sprayed and unsprayed fruit was grown during 1911 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, 13.6, 19.7 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 3, 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 19.7 per cent, was russeted on the un- 

 sprayed trees. In grove 1 the poorer results were due to the ineffi- 

 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, 11 per cent 

 second, and 16 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 Xo. 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 IX 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 gradinsr it is very difficult to show the difference in size of 



