194 THE APPLE 



that the small caterpillars can pass from one to the other by means 

 of their fine threads. A band, to be effective, must remain sticky. 

 When caterpillars are numerous, in their attempt to cross the band 

 they often bridge it with their threads and dead bodies, so that 

 other caterpillars coming later are able to ascend the tree. For this 

 reason, and in order that the caterpillars which collect beneath 

 may be killed, the sticky band should be inspected frequently. 

 If the many caterpillars which often herd below the sticky bands 

 are not killed, they will in time leave the trees for shrubbery, 

 where they are less easily destroyed, and there will complete 

 their feeding period and be transformed into moths. Insect lime, 

 Raupenleim, Tanglefoot, birdlime, printer's ink, or even axle 

 grease are among the materials most used for banding. All may 

 be dangerous to the tree and should be removed after the cater- 

 pillar season has passed. 



Destroying pupce and moths. Pupa? are commonly found under 

 the burlap and in other places frequented by the caterpillars. They 

 are often massed under large branches or in other sheltered places. 

 In similar locations the female moths may be found in numbers. 

 Both forms of the insect may be crushed by hand during July 

 and August. 



Natural enemies of the gypsy moth. The gypsy moth has some 

 natural enemies that seem at the present time to promise help in 

 the warfare of destruction. The most important is the wilt disease, 

 or " flacherie." The disease occurs naturally when the caterpillars 

 are in great numbers and find feeding scarce. It is a bacterial 

 disease which affects the intestinal canal of the caterpillar and soon 

 causes death. There are other diseases which afford help at times, 

 but none of any considerable importance. 



The large carnivorous ground beetles, such as Calosoma sp., 

 and other parasites of the gypsy moth have now been planted over 

 all the worst-infested sections, and it is believed that they are in- 

 creasing in numbers and actually becoming acclimated. Since all 

 these parasites are helps to the suppression of the gypsy moth, 

 their appearance should be studied so that they may not be destroyed 

 by mistake. 



