CALIFORNIA AVOCADO ASSOCIATION 



71 



fying to notice the large number of native seedlings that already 

 are playing an important part in the development of the Cahfornia 

 industry. In the work of improving the varieties, the Experiment 

 vStation should also be able to assist. Here also growers can do 

 a valuable work, and it seems to me that every means should be 

 taken to encourage the growing of seedlings and the selection and 

 trial of the superior types that may be discovered. I would sug- 

 gest to the Association the desirability of holding an exhibition 

 of seedlings each year at the annual meeting, and the awarding 

 each year of a medal to the seedling adjudged the best by a compe- 

 tent committee. In this way in the early days of America, the 

 Massachusetts Horticultural Society greatly stimulated the breed- 

 ing of new varieties of apples, pears, strawberries, and other fruits. 

 In this way the gooseberry in England was developed from a fruit 

 three-eights of an inch in diameter to one nearly as large as an 

 average hen's egg. 



The problems of propagation, cultivation, fertilization, irriga- 

 tion, pruning, and the like are all before us for solution. For- 

 tunately, the studies of soil management that are now being made 

 with citrus fruits will doubtless be of great value as a guide to 

 similar operations with the avocado. As an illustration, the experi- 

 ments in fertilization that have been under way at the Citrus 

 Experiment Station for the last eight years indicate the paramount 

 importance of nitrogen in fertilization and the addition of organic 

 matter to the soil. Potash fertilization has given no indication of 

 value as yet, and phosphoric acid has shown but little effect. 

 Doubtless in a general way these results will apply to the avocado 

 almost as fully as to citrus trees, as they point out the general 

 soil requirements. Again our citrus experiments have indicated 

 very forcibly the importance in orchard practice of using winter 

 cover-crops of some legume, such as bitter clover (Melilotus indica) 

 or purple vetch (Vicia atropurpurea) to supply organic matter and 

 nitrogen and keep the soil in good physical condition. Doubtless, 

 this same practice will prove just as important in groves of avo- 

 cados. 



Lastly, I wish to speak of the diseases. We are, I beUeve, and 

 I am sure you also believe, laying the foundation of what is des- 

 tined to become an important California industry. It behooves us in 

 this early stage to take full account of all diseases and strive in every 



