16 



CIRCULAR 8 2 8, U. S. DEPARTMENT OF AGRICULTURE 



Table 5. — Results of scraping and banding apple trees for codling 

 moth control, in comparison with results on plots not scraped and 

 banded, 1936-J^ 



Variety 



Number of 

 tests 



Mean number of worms per 100 

 apples i 



Treated 



Untreated 



Arkansas Black. 



Delicious 



Jonathan 



Rome Beauty. _ 

 Winesap 



5 

 9 



11 

 4 



14 



6.0 

 12. 6 

 16. 9 

 14. 2 



3. 7 



12. 

 26. 7 

 35. 2 

 32. 6 

 8. 1 



1 All differences highly significant at odds of 99 to 1, except with Rome Beauty, 

 which was not significant because of the variance in the 4 tests. 



As shown in the final results (table 4) , the percentage of worm- and 

 sting-free fruit was increased by the treatment for all plots, varieties, 

 orchards, and years. At the same time the stings per 100 apples were 

 reduced from 90 to 47, a reduction of 48 percent. 



METHODS OF SCRAPING AND BANDING 



Scraping 



Thorough scraping requires the removal of all rough bark and, 

 as far as possible, the cleaning out of all other places where the larvae 

 may hide on branches, scaffold limbs, and trunk, including a depth of 

 2 to 3 inches in the soil at the base of the tree. Unnecessary cutting 

 of the live bark should be avoided. "Peeling" the trees, as is some- 

 times done, is injurious to them, a waste of time, and entirely unneces- 

 sary either in removing the larvae or in preparing the trees for 

 banding. 



Scrapings should be caught in tarpaulins spread under the trees and 

 should be burned whenever five or six trees have been finished. A 

 cupful of stove oil or used crankcase oil poured over each pile of scrap- 

 ings will facilitate starting the fire. Old beta-naphthol bands, dis- 

 cussed elsewhere, may also be used advantageously to aid in burning 

 the scrapings. 



Scraping can be done at any time between fruit harvest and moth 

 emergence the following spring, usually before mid-April in the 

 Pacific Northwest. After moths start to emerge much of the effec- 

 tiveness of the operation will be lost ; however, it is better to have the 

 scraping completed after a few moths have emerged than not to get 

 it done, especially if the trees are to be banded. 



Broken or split limbs should be removed, and holes, cracks, and 

 narrow crotches, where larvae are likely to hide, should be filled with 

 concrete or other suitable material. Concrete has proved satisfactory 

 for this purpose. 



The upper part of the tree should be scraped first, leaving the crotch 

 to be thoroughly cleaned out after all scraping above has been finished. 



The most satisfactory scraping tools are a box or tree scraper (fig. 4, 

 A) for use in removing the rough bark, and a long-handled, narrow 



