1919] Coit-HodgsoH : Abnormal Shedding of Washington Navel Orange 285 



excessive, ami various pliysiological derangements of nutrititm are of 

 frequent occurrence. 



In many interior localities where there are l)ut few pests to hinder 

 the growth of the tree and where the climatic conditions favor the 

 production of cai-Iy maturing fruit of good color and hiirh sugar con- 

 tent, the excessive shedding of young fruits, or "Juiu' drop." as it is 

 called, is particularly exasperating to growers, who would undoubtedly 

 make much greater profits if some way could be devised to prevent 

 that part of the drop which is in excess of the normal and necessary 

 amount. An investigation of this problem wa.s undertaken by the 

 writers in response to a resolution pas.sed by the California State Fruit 

 Growers' Convention calling the attention of the university authorities 

 to the urgent need of an investigation of this subject. The results 

 secured from observations and experiments during the summers of 

 191 () and 1917 are brought together in his paper. 



Jlost of the field experiments from which our data have been 

 obtained were carried on at two stations in Kern County; one at 

 Edison in the orchards of the Edison Land and Water Company, about 

 eight miles southeast of Bakersfield, and the other about two miles 

 and a half di.stant at East Bakersfield in the orchard of Dr. C. W. 

 Kellogg. Both .stations, on account of being situated to leeward of a 

 considerable stretch of desert typical of the southern San Joaquin 

 Valley, experience the extreme climatic conditions referred to above. 

 The Navel orange matures early and is of exeellent (|uality. and wei-e 

 it not for the light crops borne this district would he considered 

 excellent for the production of Navel oranges. Under these climatic 

 conditions, unmodified, the drop occurs every year and is not de- 

 pendent on the occurrence of dry hot winds, a.s is the case in southern 

 California. 



At Edison the Navel orange trees appear healthy and \igorous, the 

 leaves and branches being quite free from fungous parasites and scale 

 in.sects. Except for an occasional slight showing of mottled-leaf disease 

 the trees may be considered very thrifty and of good size for their age. 

 which i.s eigiit years. A general view in this orchard is shown in plate 2o. 



The soil conditions are good. The type is Delano sandy loam of 

 good deptii. No general layer of hardi)an exists. Although certain 

 bodies of hard conglomerate occur occasionally these are not in layer 

 formation and do not interfere with the drainage. The soil is rich in 

 most plant foods, though low in iiiti'iiirii, wliicli. according to an 

 analysis kindly made by Dr. ('. B. Lipiiiaii. runs from .0'2'i per cent in 



