INSECTS INJURIOUS TO THE APPLE AND PEAR 611 



The caterpillars arc held in check by numerous parasitic 

 insects, some 24 species having been found preying upon them 

 by Mr. W. F. Fiske in New Hampshire,* as well as by predaceous 

 soldier bugs (Podisus spp.) and many of our common birds. 

 Large numbers of the caterpillars arc also carried off by a bacterial 

 disease. When nearly full grown the caterpillars become sick 

 and sluggish, and soon become flaccid and the skin is easily 

 ruptured, permitting the escape of the body fluids. Several 



FI.G. 464. Tent caterpillars, back and side view lj times natural size. 



species of little chalcis-flics arc parasitic in the eggs and destroy 

 a large proportion of them. Were it not for these natural enemies 

 the tent caterpillar would become a much more serious pest. 



Control. The egg-masses may easily be detected and pruned 

 off during the winter, and it would be well to leave them in a box 

 covered with netting so that the parasites may escape. Neglected 

 apple and wild-cherry trees should be destroyed, as they harbor 

 this and other pests and are usually valueless. The caterpillars 

 may be quickly destroyed by spraying with Paris green or arsenate 

 of lead just after the foliage comes out, before the trees blossom. 

 * See W. F. Fiske, Tech. Bulletin 6, N. H. Agr. Exp. Sta. 



