17 



Artificial Control 



During the last eight years, experiments have been made in Illinois 

 and Ohio to develop effective methods of control by banding, summer 

 spraying with arsenicals, summer spraying and dusting with contact in- 

 secticides, burning in hibernation, spraying and dusting with insecticides 

 in hibernation, poisoned baits oflfered as the insects are leaving hiberna- 

 tion, and cultivation of the soil. 



BANDING 



It was at first thought that the emerging beetles crawled up the 

 trunk of the tree in spring and this suggested the possibility of destroy- 

 ing them by the use of sticky bands. Preliminary experiments with tree- 

 tanglefoot bands placed singly about the trunks of the trees at varying 

 heights and doubly at various distances apart, developed the fact that 

 while fairly large numbers of beetles were caught on the bands, there 

 were about as many on the upper as on the lower where two bands were 

 used, showing that many of the beetles flew to the upper parts of the 

 tree instead of crawling up the trunk. Nevertheless a number of experi- 

 ments with bands were made, with results of which the following is 

 typical : 



On April 10 to 14, 1914, a band of tanglefoot three inches wide 

 was applied to the trunks of 500 mature Ben Davis trees in an orchard 

 of 600 trees which averaged ten to twelve inches in diameter. The loose 

 bark was scraped from the trunks and the tanglefoot was applied with 

 a wooden paddle directly to the bark, three rows in the center of the 

 experimental block being left untreated as a check. (See Figure 13.) 



On April 20 the trees banded on the 10th and 14th averaged 250 

 and 200 weevils per band, respectively, but there were many weevils on 

 the opening leaves of the trees. May 5 there was an average of 700 

 weevils per band, and June 15 practically the same. The insects were 

 distributed quite uniformly over the bands, showing that many had been 

 caught by alighting on the bands and not in crawling up the trunks. 



As a supplementary experiment, on April 20, three bands, 18, 12, 

 and 3 inches wide, were placed on one tree at a distance of 2, 8, and 

 18 feet from the ground, respectively. On May 5 the widest band con- 

 tained over 1500 weevils; the band 8 feet from the ground, 35 weevils; 

 and that 18 feet from the ground, 4 weevils. 



To ascertain whether any benefit had been derived from the band- 

 ing a number of leaves were taken at random from the banded and un- 

 handed trees, and the larval mines were counted. The results are tab- 

 ulated as follows. 



