136 



THE GYPSY MOTH. 



cation of a coating on the trunks of peach trees made early 

 in the season will prevent oviposition by the adult of the 

 peach tree borer." But it may be questioned how far this 

 covering the bark with such a material can be carried with- 

 out eventually injuring the tree. Our experiments go to 

 prove that raupenleim will usually prevent the ascent of 

 the female canker-worm moth. It is quite probable, however, 

 that after wet or cold weather, some of the moths may cross 

 the band before the warmth of the sun has rendered it viscid, 

 as the lime hardens somewhat in such weather and does not 

 again become soft until affected by the sun's warmth. 

 Climbing cutworms and many other caterpillars have been 

 caught on the bands. iSlost insects, however, seem to prefer 

 to turn back rather than attempt to cross. The larger gypsy- 

 moth caterpillars will cross when the bands have become 

 somewhat hardened by rain or cool weather, but the smaller 

 caterpillars seldom crawl over the bands. The raupenleim 

 was therefore very useful for banding trees which had been 

 cleared of the moth, providing the J^oung caterpillars could 

 be destroyed by fire or other means before they attained 

 sufficient size and strength to cross the lime. The bands are 

 useful also in preventing the ascent of such common pests 

 as the tent caterpillar and tussock moth after trees have been 

 cleared of the caterpillars or eggs of these species. * Dr. Smith 

 says that as a protection against mice and hares, *'dendro- 

 lene will serve an entire season when put on one-fourth of an 

 inch thick or more." As much cannot be said of the raupen- 



* The application of bands of insect lime appears to prevent tlie common tent 

 caterpillars from crawling either up or down trees. A wild cherry tree which con- 

 tained a great number of these caterpillars was banded with insect lime. When the 

 caterpillars had devoured all the foliage upon the tree they crawled down the trunk 

 to the band and there remained clustering upon the trunk within two feet of the 

 upper edge of the band, where they died, apparentlj of starvation. This would 

 indicate that by banding worthless trees infested by this insect it might be prevented 

 from migrating to other trees, and compelled to perish from lack of suitable food. Yet 

 no instance of this kind has been observed with any other insect, and no record was 

 kept of the number of caterpillars originally on the tree, so it is impossible to tell 

 how many may have escaped. It is not safe to base any conclusions on a single 

 observation of this sort. It is given here merely to show the necessity of further 

 observation and experiment with insect lime, which can probably be used in many 

 ways as a preventive to insect attacks or an insecticide application. 



The application of the insect lime to egg-clusters has already been mentioned 

 (page 125), but it has been superseded in Massachusetts by more economical and 

 effective measures (page 123). 



