PREFACE. The closing decades of the nineteenth century have seen great changes in the principles of citrus fruit culture in America. Twenty years ago the amount of fruit pro- duced was comparatively small, now the industry has at- tained a place among the large horticultural industries of this country. Then, at most, a few hundred boxes of fruit were produced annually now the crop is counted not by hundreds but by millions of boxes. The pomelo was scarce- ly known and the lemon was a fruit imported almost en- tirely from the Old World. Then, the means of transportation closed many a desirable tract of land through which the railroad now runs and from which large quantities of fruit are now shipped. Then, the methods of combating insects and fungous diseases were less perfectly under stood than now. In those days, the fertilizers applied to the soil were mostly made at home, now the nitrogen, phos- phorus and potash, deemed so essential for the production of first-class fruit, in many districts, can be obtained as commercial commodities in any market. Numerous de- vices are now successfully employed in protecting trees and fruit against the effects of frost and freeze, then, noth- ing of the kind was attempted or in fact deemed neces- sary. Then, cover crops were not considered in the light in which they now are. Then, the citrus industry in the New World was more or less firmly linked to that of the Old. Now, we have an American industry on the large, broad lines of American progress. During these past twenty years no work dealing with the fruits of the genus citrus has been produced. The literature has not kept pace with the growth, the de velopment, and the new phases of the industry. To fill a long-felt want, this volume after many urgent appeals from those interested in and engaged in the industry has been produced in the hope that it may, in some measure at least, supply the lack of reliable, up-to-date information. In its preparation the author has had the hearty cooperation, assistance and sympathy of many friends. The chapter on Fertilizers and Fertilizing has been reviewed by Prof. H. K. Miller, of the University of Florida, that on Cover Crops, by Prof. John Craig, of Cornell University, while the chapter on Insects Injurious to Citrus Trees, has been revised and largely re-written from his former publi cations, by Prof. H. A. Gossard. of the University of Flor ida. The chapter on Pot Culture of Citrus Fruits, has been revised by Mr. E. N. Reasoner, of Oneco, Fla. Dr. N. L. Britton, Dr. D. T. MacDougal and Miss Anna Mur- ray Vail, of the New York Botanical Garden, have made it possible to examine the older works on citrus fruits, and have rendered much valuable assistance. Prof. A. W, Blair, of the University of Florida has contributed an analysis of one of the cover crops, heretofore unpublished All the drawings and some of the photographs used in the illustrations were made by Miss Lucia McCulloch for- merly assistant in the Department of Botany and Horti culture in the University of Florida. Prof. Dorsey now of the Mechanics Institute, Rochester, New York, contrib uted a number of photographs, while those illustrating California scenes were secured through the kindness of Prof. C. W. Woodworth, of the University of California, VII Mr. John Isaacs, of the California State Board of Horti- culture and Mr. V. J. Allen, of Bonita, Cal...