34 



use of the blow torch is of little practical value, and under some condi- 

 tions may prove harmful because of the possible injury to low-hanging 

 branches and because it may result in the weevils leaving hibernation 

 early. 



Burning with the blow torch is decidedly effective in partly culti- 

 vated orchards where the beetles are forced to concentrate for hiber- 

 nation around the base of the tree because the spaces between the tree 

 rows are either barren or the covering is not such as to attract the 

 beetles seeking winter quarters. Where the orchard is in heavy sod 

 of long standing, burning is not a satisfactory means of control be- 

 cause so much time is required for the operation and because the 

 beetles do not concentrate around the base of the tree. 



CULTIVATION 



By all odds the cheapest and most effective control measure tried 

 under Ohio conditions is clean cultivation, the object being either to 

 destroy the insects in hibernation by plowing them under in fall or 

 early winter, or else by summer cultivation to eliminate all sod and 

 refuse in which they could find winter quarters. 



In November, lOlS, four acres were plowed to a depth of 4 inches 

 in the midst of the Delaware Apple Company's 40-acre orchard at 

 Delaware, Ohio, then owned by Mr. Hudson. This particular four 

 acres was chosen because it was the very worst infested section in 

 the property. It had been in grass for twenty years or more, and a 

 very tough sod had developed. Only 15 to 20 square feet remained 

 unturned about the base of each tree, and part of this was unsuitable for 

 the hibernation of the beetles because it was covered with cinders, and 

 because some of the protecting refuse blew away. 



The following summer the injury in the plowed plot was very 

 slight, particularly from the beetles as they left hibernation in spring 

 and from the mining larvae ; but it became somewhat greater when 

 beetles of the new generation spread over the cultivated plot from sur- 

 rounding trees. However, the total injury to trees in the cultivated 

 plot was not of commercial importance. 



This original four-acre plot has been kept in clean cultivation up 

 to the present time, and at no time during the four seasons have the 

 beetles caused commercial injury. Indeed during most of the time it 

 has required searching to find evidence of the 'beetles' presence in 

 the more, central parts of the plot. Moreover, the cultivation has 

 proven of benefit to the trees. They have taken on new vigor and have 

 been markedly more productive than trees of the same age and variety 

 where the ground had not been plowed. 



In the summer of 1821 the remainder of the orchard was broken 

 up by numerous cuttings with a double disc and Fordson tractor, the 

 latter so covered as to pass under low limbs without injury t<3 them 

 (see Figure 16). The following season saw a marked limitation in the 



