68 



ANNUAL REPORT 1918 AND 1919 



except by the experimenter. They have not withstood the cold at all 

 well, and from the appearance of the trees I have seen do not seem to be 

 well adapted to some of the other conditions, possibly the extreme warm 

 period in summer. Personally, I am rather partial to the flavor of this 

 fruit but find few who share my judgment among those who are most 

 familiar with the best Mexican and Guatemalan varieties. Nurserymen 

 should be especially careful to keep their stock plantings free of West 

 India seed. 



Among our better known kinds which are recommended for plemting, 

 the Fuerte impressed me as withstanding cold much better than the others, 

 and the Taft seemed to be the most severely injured. There appeared to 

 be considerable difference between these two varieties. Other varieties 

 recommended for commercial planting and a large list which are being 

 grown experimentally, or in a small way, excluding some of the thin- 

 skinned Mexicein varieties and those from the West Indies, fall pretty well 

 between the two above extremes and appear to differ but little in their 

 cold resistsmce. 



Special care should be given new introductions to prevent them from 

 being eliminated by cold while the trees are young and before the value 

 of the fruit or the cold resistance of the tree has been proven. Mr. Knight 

 solved this problem very satisfactorily on his place during the past winter 

 and his method of spraying trees with water while low temperatures pre- 

 vailed should be considered by those equipped for it. 



In conclusion avocado growers should remember that the weather 

 breaks a record almost every day somewhere and make their plantings and 

 care for their trees accordingly. 



THE AVOCADOS OF MEXICO: A PRELIMINARY REPORT 



Wilson Popenoe, Agricultural Explorer for the College 

 OF Agriculture. University of California* 



The outstanding importance of Mexico as a field for the study of 

 avocados and avocado culture is evident at a glance. The great extent 

 of its territory, the immense range in elevation cuid consequent differences 

 in temperature, the widely diverse soils found in various parts of the repub- 

 lic, — these and other factors combine to produce an almost endless series 

 of environmental conditions. Added to this the fact that avocados are not 

 only cultivated in abundance, but are found also in the wild state, and 

 nothing further is needed to convince the student of avocado culture that 

 here are opportunities for investigation and research such as are offered by 

 no other country in the world. 



In the development of the avocado industry in California the great- 

 est factor up to date has been Mexico. Glance over a list of the varieties 

 which have been tested in California, and you will find that the majority of 

 them are of Mexican origin. It is natural, therefore, that the horticulturists 

 of California should be deeply interested in Mexican avocados and avo- 



*Now Agricultural Explorer for the Office of Foreign Seed and Plant 

 Introduction, Bureau of Plant Industry, U. S. Dept. of Agriculture. 



