64 MANUAL OF TROPICAL AND SUBTROPICAL FRUITS 



shade often results in serious sunburning of the more tender branches, 

 and the low state of vitality lays the tree particularly liable to the 

 inroads of disease, especially of the anthracnose fungus which seldom 

 loses such an opportunity for making an attack. Finally the tree is 

 compelled to drop practically its entire crop of fruit and is left in a 

 condition which means, at the very best, a set-back of two seasons ifl^ 

 its development and not infrequently results in its actual death. 



"To obviate overblooming, particularly in the case of young trees, 

 is very difficult, for the better the cultural condition of the tree, the 

 more likely this is to occur. The usual procedure has been to thin 

 the over crop of fruit and this method of handling works quite satis- 

 factorily provided the set-back to the tree has not already been brought 

 about through the excessive bloom. However, the avocado requires 

 a longer period than most fruits between the first appearance of the 

 bloom and the setting of the fruit and it often happens that the damage 

 to the tree has made considerable advance before relief by stripping 

 can be obtained. In this event removal of the entire crop and further 

 careful attention is necessary. 



" In an effort to overcome this difficulty, I have during the past two 

 seasons resorted to frequent applications of fertilizer, in order to offset 

 the heavy drain upon the vitality of the trees during the blooming 

 period. In the spring of 1916, following a season favorable to growth, 

 the avocado trees at Medora Grove began to bloom about the middle 

 of March. Immediately afterward a light application of fertilizer, 

 carrying ammoniates from readily available sources was made. The 

 bloom was the heaviest known in a number of years and persisted until 

 about the middle of April. Between April 15th and 20th, another 

 light application of the same fertilizer was made and this was followed 

 by a third application the latter part of May, when a fertilizer some- 

 what higher in phosphoric acid, largely derived from low grade tank- 

 age, was used. As a result of this treatment a full crop of fruit was 

 set and in most cases carried through to maturity without damage to 

 the trees. When an over crop was set at first, as a rule dropping took 

 place without a reduction in vitality, until the proper carrying capacity 

 had been reached, and the remainder of the crop was matured. In a 

 few cases stripping was necessary, but among nearly two thousand 

 trees of varying ages, not more than eight or ten showed any appre- 

 ciable damage." 



In both California and Florida, avocados sometimes crack 

 open while hanging on the tree. This has occurred in varieties 

 of the Guatemalan and Mexican races, but is most common in 

 the latter. The cracks are usually situated towards the apex 



