72 
BULLETIN 813, II. S. DEPARTMENT OE AGRICULTURE. 
securing the investigational performance records the same standard of 
picking was followed each month as that used in the regular commercial 
picking. Table XIV shows the ring size used for Green-grade fruit at 
each picking from July, 1911, to June, 1917, inclusive. Fortunately 
for this study of seasonal variation, it will be noted that there was 
no change in ring size during the last two years of the study period. 
Fruit of the Tree-Ripe grade is sometimes picked as soon as it appears, 
and sometimes it is not picked until it reaches a certain size, which 
is usually smaller than the standard being used for fruit of the Green 
grade. The practice varies in different orchards, and in any one or- 
chard it is usually influenced by climatic and market conditions. On 
this account it is believed that a consideration of the fruit of the Green 
grade alone will give the truest index of the production habit of the 
various strains but the data for the fruit of the Tree-Ripe grade are 
included as a matter of interest. 
Table XIV. — Diameter of rings used in picking fruits of the Green grade from the lemon 
trees of the Eureka variety in the investigational performance-record plat during the 
5-year period from July, 1912, to June, 1917, inclusive. 
Month. 
Diameter of picking ring for 
Green-grade-fruit (inches). 
July 
August 
September 
October... 
November 
December. 
1911- 
12 
2A 
2A 
2A 
2& 
2A 
2& 
1912-1913- 
13 14 
2J4 
m 
2H 
2& 
2& 
2A 
Ol o 
910 
1914- 
15 
2-^ 
2& 
2& 
2A 
2A 
1915- 
16 
2-h 
2& 
2A 
2^ 
2& 
2^ 
1916- 
17 
2^ 
2A 
2A 
2h 
2& 
2& 
Month. 
January. . 
February 
March 
April 
May 
June 
Diameter of picking ring for 
Green-grade fruit (inches). 
1911- 
12 
2& 
2A 
2A 
2& 
2A 
2& 
1912- 1913- 
13 14 
1914- 
1 
2tt 
m 
m 
2^ 
2A 
1915 
16 
2& 
2& 
2-h 
2^ 
2-h 
1916- 
17 
2A 
2A 
2A 
2A 
2& 
In figure 12 the graphs representing the monthly production of 
fruit of the Green and Tree-Ripe grades are arranged by strains from 
left to right, according to their rank for average total production as 
shown by Table XL To bring out more closely the variations in pro- 
duction each month between the trees of the different strains the data 
were rearranged as shown in figure 13. Each graph represents the 
proportions of fruit produced during a month by the trees of the vari- 
ous strains, which are presented in each month in the same order from 
left to right as in figure 12. 
The low production in January of fruits of both the Green and Tree- 
Ripe grades by the trees of all the strains is quite marked, and it 
is probable that if all conditions had been normal the records would 
indicate a gradual upward curve at that time instead of the break that 
is shown. Table IX shows that in 1914 and 1916 the time between 
the November and December pickings was longer than usual, which 
