ORCHARD, GARDEN, AND FIELD INSECTS 135 



thirty female cankerworm moths a day. ... If the aver- 

 age number of eggs laid by each female is one hundred 

 and eighty-five, one chickadee would thus destroy in one 

 day five thousand five hundred and fifty eggs, and in the 

 twenty-five days in which the 

 cankerworm moths crawl up 

 the tree, would rid the orchard 

 of one hundred and thirty- 

 eight thousand seven hundred 

 and fifty." These birds also 

 eat immense numbers of 

 cankerworm eggs before they 

 hatch into worms. 



Treatment. The inability 

 of the female to fly gives us 

 an easy opportunity to prevent 

 the access of the larval off- 

 spring to the foliage of our 

 trees, for we know that the 

 only highway open to her or 

 her larvae leads up the trunk. 

 We must obstruct this high- 

 way so that no crawling crea- 

 ture may pass. This is readily 

 done by smoothing the bark 

 and fitting close to it a band 

 of paper, making sure that it is tight enough to prevent 

 anything from crawling underneath. Then smear over the 

 paper something so sticky that any moth or larva that 

 attempts to pass will be entangled. Printer's ink will do 

 very well, or you can buy either dendrolene or raupenleim. 



FIG. 128. EGGS OF THE FALL 

 CANKERWORM 



