74 



BULLETIN 813, V. S. DEPARTMENT OF AGEICULTURE. 



these strains is so low as to make them expensive boarders for the 

 grower. 



This difference in time of production between the trees of two of 

 the most important strains is very clearly shown in figure 14. This 

 diagram indicates the relative percentage of the total yield of fruit of 

 the Green grade that was produced each m.onth by the trees of the 

 Eureka and Shade-Tree strains, showing the large proportion of fruit 

 borne by the trees of the Eureka strain from February to May, in- 

 clusive. During that period the trees of the Shade-Tree strain were 

 yielding a relatively small proportion of their crop, the time of their 

 heaviest production being from September to December, inclusive. 



Additional data regarding the season of production is given in 

 Table XV, which shows the production from the entire study plat at 

 each picking during the 3-year period from July, 1914, to June, 1917, 

 inclusive. This is the record of the number of field boxes of fruit 

 produced each month, including the culls. Stated in this concise 

 form, the normal variations in yield from month to month are clearly 

 shown. A study of the second half of the table shows that there are 

 variations in the season of production in succeeding years. These 

 differences are probably due partly to varying climatic conditions in 

 the different years, partly to unavoidable changes in the intervals be- 

 tween the pickings, partly to changes in the size of the ring used for 

 picking the fruit of the Green grade, and partly to variations in the 

 plan for picking the fruit of the Tree-Ripe grade. 



Table XV. — Fruit yields of the lemon trees of the Eureka variety in the investigational 

 -performance-record flat for each month during the 3-year period from July, 1914, to 

 June, 1917, inclusive. 



[The yields are expressed in terms of the number of field boxes of fruit, including the culls.] 



Month. 



Total production (held boxes). 



1914-15 



1915-16 



1916-17 



3-year 

 total. 



Monthly percentage. 



1914-15 1916-16 1916-17 



July 



August 



September. 



October 



November . 

 December.. 



January 



February . . 



March 



April 



June. 



Total. 



Heaviest . 

 Lightest . 



18 

 51 

 16i 

 19i 

 43J 

 92 

 133 

 112 

 95 

 147 

 126J 

 62 



25 

 39 

 50i 

 564 

 44i 

 69 

 32 

 50-J 

 84 

 97| 

 143 

 37 



10 



19i 

 26J 

 53i 

 18 



76J 

 123J 

 109 



18 



57 



53J 



77 



954 



114| 



214J 



63i 



t200| 



217J 



368i 



3784 



117' 



2.40 



0.73 



2.20 



2.60 



5.79 



12.25 



1.83 



14.91 



12.65 



19.57 



16.84 



8.25 



3.43 



5.35 



6.93 



7.76 



6.07 



9.47 



4.39 



6.93 



11.53 



13.42 



19.63 



5.08 



2.93 

 1.88 

 2 09 

 4.08 

 5.55 

 11.20 

 3.77 



16.02 



25.86 



22.83 



3.77 



7511 



7284 



477i 



1, 957:1- 



April. 

 August. 



May. 

 July. 



April. 

 August. 



May. 

 August. 



2.91 



2.73 



3.93 



4.88 



5.84 



10.96 



3.26 



a 10. 26 



11.10 



18.81 



19.34 



5.98 



a February is credited with half of the production for March in 1917. 



In order to show in a more striking manner the variations in fruit 

 production by trees of the different strains, Table XVI has been pre- 

 pared. This presents the calculated yields per acre of fruit of the 



