118 BXTLLETIN 624, XJ. S. DEPARTMENT OF AGRICULTURE. 
small size. Since that time this prejudice has gradually disappeared 
and thousands of buds from such wood have been used successfully 
in both experimental and commercial propagations. 
If bud wood is desired at times when the fruits are unripe or when 
the bud wood is not in condition for use, it should be cut when the 
ripe fruits are available for inspection and stored in sterilized moss 
until needed. 
The identification of a valuable strain is of vital commercial im- 
portance to the entire orange industry. The segregation of the in- 
ferior strains is of interest only from an experimental standpoint. 
The propagation of valuable strains will result not only in an in- 
creased production, but what is equally important, in a uniform pro- 
duction of crops of greater commercial value. 
TOP- WORKING UNDESIRABLE TREES. 
Healthy Valencia orange trees of inferior or undesirable strains 
can be successfully top-worked, using the kind of bud wood de- 
scribed in the preceding paragraphs. This bud wood can be used 
either as grafts or, as is the usual practice, for budding directly into 
some of the main limbs. 
The selection of trees to be top-worked should be made before their 
fruits are picked. TVhile trees of some inferior strains are easily 
recognized from their habits of growth or foliage characteristics, it is 
desirable wherever possible to base the selection of trees to be top- 
worked on their performance records and fruit characteristics. The 
selection of bud wood for top-working purposes should also be based 
on individual-tree performance records associated with an intimate 
knowledge of tree and fruit characteristics secured from careful 
observations in the orchards. 
In top-working established trees, two or three of the main limbs 
should be selected for the foundation of the new heads. Two buds 
should be inserted in each of these limbs, from 12 to 24 inches above 
the fork of the trunk. After the buds have united with the older 
limbs, these limbs should be cut off about 6 inches above the point of 
insertion of the buds, and the cut surfaces covered with grafting wax 
or some pruning compound. The trunks and remaining portions of 
the limbs should be heavily whitewashed or otherwise protected, in 
order to prevent injuries from exposure. About a year later the 
stubs of the original limbs should be cut back close to the young 
buds, making the cuts oblique in order to facilitate their healing, and 
the cut surfaces should be again waxed or painted. In every case 
great care must be exercised in removing all sprouts from the trunk 
and old limbs in order to develop the new heads entirely from the 
inserted buds. 
