11 
affected by the difficulties in fumigation presented by excessive 
height of trees, closeness of planting, unevenness of ground, and other 
conditions. The systematic treatment of groves to overcome these 
difficulties, so that the trees may be easily fumigated, will not only 
be of value in this respect, but will constitute a good cultural practice. 
Trees planted too closely for fumigation to be practicable are too 
close for best results in productiveness. Limiting the height of trees 
by pruning not only lessens the expense of fumigation, but reduces 
the expense of picking the fruit without reducing the quantity. 
a 22122777 2 2) 
ere 
ete 2} | ia] SE 
=e a HES asl = Bar 
Hee nO SSSEerce Hel 
ea Sane) be 
515 + PIE [kg i 
=a aS 
180 827/85 8 
om Scececcend aan 
[19 | 
ae SSoscnee = 
21 |22\2 
23| 24/26/27 
Lig {2 
+ sossizoasisose 
BS 
RRS 
TATA 
OD 
BSRRs| [ZIRVSl | 
° 
g S 
DOVE Brot TI 
9 
a 50167 168 OzloG 123 
8 |103|/O7| IH [115/119 [123] 127 
aS 98 |103] 1071/2 |116|/20)124|128 133474 
76 98 [lo2[107,2[Ni7 121 ]125 139176. 
Fic. 4.—Dosage schedule for use in fumigating for the citrus white fly. (Original. ) 
In preparing for the fumigation of a grove, if the branches inter- 
lock to any extent, either pruning of branches or transplanting of 
alternate trees or rows of trees is advisable. Deadwood on the outer 
parts of the trees should be thoroughly removed in all cases to avoid 
the tearing of tents. Watershoots should be thoroughly removed 
at the same time, since about 1 per cent of the white fly pupz present 
during the winter months survive fumigation and the resistance of 
the insects on watershoot leaves is much greater than elsewhere on 
the trees. 
[Cir. 111} 
