SCRAPING AND BANDING FOR CODLING MOTH CONTROL 



21 



medium, and large trees at a wage of 60 cents per hour is shown in 

 table 6. Bands on both trunks and limbs on older, larger trees would 

 triple the cost for the banding (but not for the scraping) and would 

 increase the total costs by 30 to 40 percent. The worm captures would, 

 however, be increased by approximately 50 percent. Estimates on 

 the net gain from scraping and banding under certain conditions are 

 given by Yothers and Carlson {26) . 



Table 6. — Approximate cost of scraping and handing apple trees in 

 the Yakima district of Washington 



Size of tree 



Small (rough bark) 



Medium 



Large 



Maximum 



fruit yield 



per tree 



Time re- 

 quired for 

 scraping 





Cost per tree 



Labor 



(average at 



60 cents 



per hour) 



Material 



Boxes 

 10-15 

 20-35 

 40-50 



Minutes 

 10-15 

 20-35 

 40-50 



Cents 

 10-15 

 20-35 

 40-50 



Cents 

 3- 5 

 5- 8 

 8-10 



Total 



Cents 

 13-20 

 25-43 

 48-60 



SUMMARY 



Investigations on the value of scraping and banding apple trees to 

 destroy the larvae of the codling moth (Varpocapsa pomonella (L.) ) 

 and related studies were carried on near Yakima, Wash., from 1935 

 to 1943. 



On trees not previously scraped and banded 85 percent of the over- 

 wintering larvae were located on the trunks and scaffold limbs, 13 

 percent on other branches, and the remainder in trash and soil. On 

 such trees 86 percent of the larvae were in rough bark and crotches. 

 On trees that had been scraped and banded the previous season, only 

 41 percent were on the trunks and scaffold limbs, 50 percent on the 

 secondary branches, and 9 percent in trash and soil. Only 46 percent 

 of the larvae were in rough bark and crotches. The average popula- 

 tion per tree, however, was reduced from 168 to 22. 



Thorough scraping at any time between apple harvest and moth 

 emergence the following spring destroyed about 80 percent of the 

 overwintering population the first season. On trees that had been 

 scraped the previous year only about 50 percent of the larvae were 

 removed by the second scraping. 



On well-scraped trees 50 to 60 percent or more of the larvae were 

 trapped in the bands. 



Chemically treated bands on the scaffold limbs caught 29 percent 

 more larvae than did bands on the trunks, and a combination of both 

 trunk and limb bands caught 50 percent more than did trunk bands 

 alone. 



The heavier the infestation the greater was the proportion of larvae 

 caught in bands as they were leaving the fruit. 



Scraping and banding were most effective on varieties such as 

 Jonathan and Kome Beauty, which were readily scraped. 



Larvae entering beta-naphthol bands were killed within a few hours 

 to a day or so. The higher the temperature the quicker was the kill. 



Sticky banding materials were comparatively ineffective. 



