12 BULLETIN 71, HAWAII EXPERIMENT STATION 



of the fruit. The crown or head, where the first, or framework, 

 branches develop, should be 2 to 3 feet above the surface of the 

 ground, depending on the frequency and severity of the winds 

 to which the tree is exposed (fig. 2, A, d) . The lower the crown, 

 the less likely it is to be injured by strong winds, but a crown 

 within 3 feet of the ground is suitable for orchard culture. At 

 the end of a year the trunk should be headed back to about a 

 foot above where the lowest branch of the crown is desired. All 

 other growth than that intended for framework should be re- 

 moved from time to time during the first season. 



The young lateral branches forming the framework should 

 be cut back to 8 to 10 inches to permit secondary branches to 

 develop. These secondary branches are later thinned, leaving 

 only two or three of the framework branches on the outside 

 (fig. 2, A, e) . Pruning should be done preferably following the 

 gathering of the crop which, in most parts of Hawaii, is about 

 midwinter. In the removal of large branches the under side 

 should be cut about an inch deep Vo foot from the trunk. Then 

 the limb should be cut on the upper side in front of the under cut 

 to avoid danger of splitting the tree. The stub should be cut off 

 close parallel to the trunk. 



All cuts more than half an inch across should be covered 

 with melted asphaltum paint or with melted grafting wax to 

 prevent decay or the entrance of insects. Exposed parts of 

 the trunk or of the branches should be liberally coated with 

 whitewash to protect them from sun injury. Shamel, Pomeroy, 

 and Caryl (2i, p. 31) state that trees propagated from fruit- 

 bearing wood secured from superior performance record parent 

 trees of fruitful strains require little pruning under normal con- 

 ditions. 



The tools used in pruning citrus trees are simple and compara- 

 tively inexpensive and include a hand shears about 9 inches long, 

 a saw, and a knife (fig. 2, B). The shears used at the station 

 consists of a single blade and a guard (fig. 2, B. d). A small 

 curved saw having a continuous series of teeth along one edge 

 of the 12-inch or 14-inch blade (fig. 2 B. e) is used for large 

 limbs. A 7-inch or 8-inch knife is used to smooth off surface 

 wounds before they are painted (fig. 2, B, /). This knife should 

 be large, strong, and sharp. A long-handled tree pruner may be 

 used to remove small branches in the tops of tall trees (fig. 2, B. 

 h). A strong, light ladder may be used for reaching parts of 

 the tree not readily accessible from the ground (fig. 2, B. i) . 



INSECT ENEMIES 

 The Mediterranean Fruit Fly 



The Mediterranean fruit fly (Ceratitis capitata) reached Ha- 

 waii from Australia in 1907 (2, p. 9), although it was not dis- 

 covered here until 1910 {2, p. 7). Conditions in Hawaii are 

 favorable to its rapid increase. The life cycle of this destructive 

 pest is described by Ehrhorn (9). Government entomologists 

 and others have done much to control the fruit fly through a 

 study of its habits and the introduction of destructive parasitic 



