SHADE TREE INSECTS 21 



Life History. Farther south the fall webvvorm may have two generations; 

 in northern Connecticut, Massachusetts, and northward, however, it is reported 

 to have only one. 



The adult moths are abroad in June and Jul\' and lay their eggs in clusters on 

 the under side of a leaf. The eggs soon hatch and the tiny young caterpillars 

 working gregariousK- begin at once to enclose in a silken web the leaves on which 

 they feed. As more food is needed, the web is extended to include more leaves 

 until finally the webs may be of considerable size and include whole branches. 

 These webs usually become noticeable during August and September. The 

 young caterpillars feed mostly on the upper surface of the leaves, skeletonizing 

 them, but the older larvae eat the entire leaf leaving only the midrib and larger 

 veins. After feeding for about a month the caterpillars become mature, leave the 

 nest, wander off individually, and soon select a protected place in which to 

 pupate — under loose bark or in a crevice of a tree, on a fence, or under rubbish, 

 leaves or stones on the ground. Some may even burrow below the surface. The 

 lar\a spins a loose cocoon in which long hairs from its bod>' are enmeshed. It 

 then pupates and passes the winter in that condition. The adult moths appear 

 the following June. 



Control. Spraying the trees with lead arsenate at the rate of 3 to 4 pounds of 

 the powder to 100 gallons of water with 2 pounds of flour or 1 pound of calcium 

 caseinate added should protect the foliage from injury if done when the cater- 

 pillars first appear. It is difificult to kill with this spray caterpillars that are 

 more than half grown. 



When the webs are within reach of pruning tools thej' may be removed and 

 burned, provided they have not become so large that removing the infested parts 

 disfigures the tree. When the webs can be reached by hand and are still small, 

 they may be removed and the caterpillars crushed or dropped into a can of 

 kerosene and water. 



Burning the webs on the tree by means of an ignited kerosene-soaked rag on a 

 pole is not advised because the branches may be scorched in the process. 



Parasites, predators, and diseases do much to hold this insect in check. 



Britton, \V. E. Conn. State Ent. Rpt. 17:319-324. 1918. 



Britton, W. E., and Friend, R. B. Conn. Agr. Exp. Sta. Bui. 369:281-282. 1935. 



Felt, E. P. N. Y. State Mus. Mem. 8(1) :142-146. 1905. 



Fernald, C. H. Hatch Exp. Sta. Mass. .A.gr. Col. Bui. 20:10-12. 1893. 



Fernald, H. T. Mass. .A.gi-. Exp. Sta. Bui. 125:54. 1908. 



McDaniel, E. I. Mich. Agr. Exp. Sta. Spec. Bui. 243:18-20. 1933. 



Riley, C. V. U. S. Dept. Xgv. Div. Ent. Bui. 10:33-53. 1887. 



Snodgrass, R. E. Smithsonian Publication 2693: 395-414. 1923. 



White-Marked Tussock Moth 



Hemerocampa leucostigma S. & A. 



This native insect is generally distributed from Nova Scotia to Florida and 

 west to Nebraska but has been most troublesome in southern New England and 

 the Middle Atlantic States. It is more of a pest in cities and towns than in rural 

 sections, and prefers the foliage of broad-leaved trees such as poplar, elm, linden, 

 soft maple, and horsechestnut, but feeds on many others, including coniferous 

 trees such as spruce, fir, larch, and cypress. 



The young caterpillars feed at first on the lower leaf surface but later devour 

 all the tissue, leaving only the midrib. The caterpillars have been reported to 

 girdle the twigs of elm by eating the bark around the twig near the beginning of 

 the season's growth. The affected tips soon die, break off, and fall to the ground. 

 The fruit of orchard trees is occasionally attacked. 



