SCRAPING AND BANDING FOR CODLING MOTH CONTROL 



Table 2. — Proportion of larvae that left the fruit and were captured 

 in beta-naphthol bands, 1935-^1 



Variety 



Year 



Trees 



Larvae captured— 

















Leaving fruit 



In bands 







Number 



Number 



Number 



Percent 





( 1935 



5 



213 



183 



86 





1936 



9 



1, 109 



698 



63 





1937 



26 



6,098 



3,769 



62 



Jonathan 



< 1938 



19 



10, 849 



7,274 



67 





1939 



18 



2,545 



1,321 



52 





1940 



6 



2,517 



1,290 



51 





I 1941 



6 



166 



86 



52 



Total _ 





89 



23, 497 



14, 621 



62 









Rome Beauty __ 



J 1939 

 I 1940 



2 

 10 



268 

 938 



119 



465 



44 

 50 



Total 





12 



1,206 



584 



47 











( 1936 



2 



28 



14 



50 





1937 



7 



1, 312 



794 



61 



Winesap 



J 1938 

 ) 1939 



4 



6 



1, 598 

 412 



625 

 165 



39 

 40 





1940 



8 



1, 116 



396 



35 





( 1941 



12 



165 



54 



33 



Total . _ 





39 



4, 631 



2,048 



43 











( 1935 



5 



859 



691 



80 





1936 



6 



213 



117 



55 



Delicious 



{ 1938 



4 



1, 558 



487 



31 





1939 



6 



1, 180 



353 



30 





{ 1940 



6 



575 



158 



27 



Total 





27 



4,385 



1,806 



45 









Grand total 





167 



33, 719 



19, 059 



57 









any worms that had recently left the fruit to enter them. Dropped 

 fruits at the preharvest examinations and picked wormy fruits were cut 

 open to make certain that the larvae had left. In every test but one 

 a larger percentage of the larvae were caught in the three preharvest 

 examinations than in the after-harvest examinations. For all or- 

 chards and in all preharvest examinations the percentage caught before 

 picking averaged 82, but the after-harvest percentage dropped to 40. 

 In other words, about twice as many of the larvae left the fruit before 

 the preharvest examination as left it thereafter. The seasonal av- 

 erage of larvae captured was 61 percent, which is substantially the 

 same as the 57 percent shown by the first method (table 2). 



Since the growing larvae feed within more than one apple, it seems 

 that by this method the number of larvae caught in the bands, as 

 compared with the number of exit holes, is greatly underestimated. 

 Nel (6) stated that a single well-grown larva can leave several exit 

 holes against which but one capture in the bands can be recorded. 



