322 



( iiKiic or less, as corrected for autumn rainfall), the end of the stage may 

 be predicted a week or more in advance. Individual variation may permit 

 the first moth to emerge when the sum of developmental units is 8% less 

 than the normal total, so that this correction should be applied in predic- 

 tion of first appearance. 



e. If temperatures above 62° F. occur during cloudy weather or 

 after sunset, the moths will begin laying eggs two days after emerging; if 

 the temperatures are lower, egg-laying is delayed. 



Eggs. 



From the time the first moth is estimated to have begun laying eggs, 

 proceed with the hygrothermograph records and the velocity values from 

 Table I, as in the case of the pupa, but consider the approach of a total of 

 3864 developmental units as the time for hatching of the eggs. 



Larvae. 



From the observed or estimated date of hatching of the eggs of the 

 first generation, in order to compute the time in the apple and in the 

 cocoon, use the rates of development for one-hour (or two-hourj read- 

 ings of temperature as given on Table V (p. 323). As the sum 

 approaches 18,000 (more or less, depending upon rainfall, as shown on 

 Table VI), forecast the time of pupation of the first generation. 



The same procedure may be carried through the season for the later 

 generations, using Tables I-IV for pupae and eggs and Tables V and VI 

 for larvae. Attention must always be given to corrections for individual 

 variation (see footnotes to Tables IV and V) and to corrections for fall- 

 ing temperatures, as shown in Table IV. 



Table IV. Falling-Temperature Corrections for Pupa ana Egg. 

 (Based on Tables IX and X.) 



Week of Falling 

 Temperature. 



Ratio to Normal 

 Total. 



Developmental Total.' 



Pupa, 

 (hour units) 



Egg. 

 (hour units) 



• Note: Individual variation permits first emergence when the accumulated num- 

 ber of developmental units is S% less than the totals given here. These develop- 

 mental totals represent averages for all individuals of any lot. The reverse cor- 

 rection of 2% per week of rising temperatures may be applied for the late-pupating 

 individuals of the hibernated generation. See ratio of actual to standard time in 

 Fig. 28. 



