TREE INSECTS AND THEIR CONTROL 203 



When fully developed the caterpillar 

 becomes a chrysalis resembling a sea-shell, 

 which is fastened to a limb, and which 

 develops into a butterfly, which in turn 

 lays eggs. 



damage to the tree the twigs carrying the 

 caterpillars should be cut off. When this 

 is done the caterpillars may be easily 

 destroyed by burning, by dipping in 

 kerosene or by crushing. 



Fall Webworm 



Habits This pest may be recognized 



and by its tent-like web containing 



Damage, a quantity of hairy caterpil- 

 lars together with skeletonized 

 leaves, the latter usually brown. The 

 young webworm, or pupa, spends the 

 winter in silken cocoons, in cracks and 

 crevices of fences or tree boxes, under 

 doorsteps, on basement walls, or among 

 sticks and rubbish. In May the pupa 

 becomes a moth, which lays its eggs on 

 the underside of leaves. The young 

 worms when hatched feed in groups and 

 construct their web to cover several 

 leaves, sometimes an entire limb of con- 

 siderable size. In July, when fully grown 

 the worms crawl down the tree. A second 

 crop develops in August in temperate 

 climates, and in the South a third crop is 

 known. 



To provide suitable apparatus, the spraying should be cooperative. All trees 

 should be sprayed as those left untreated would communicate the web-worms to 

 others near at hand. 



Forest Tent Caterpillar 



Remedies. Like the bagworm, the fall 

 webworm has natural ene- 

 mies, which usually keep it in check. 

 When artificial control is necessary, the 

 best method is to destroy the cocoon in 

 winter by hand picking and burning. The 

 burning of the tents is also necessary. If 

 foliage becomes affected it should be 

 sprayed with lead arsenate. To apply 

 the spray a barrel pump mounted on a 

 horse-drawn cart may be used in a small 

 community, with good results. This 

 should have fifty feet or more of garden 

 hose. A ten foot bamboo pole, carrying 

 the spray nozzle at the end, is helpful in 

 causing the spray to reach the upper 

 limbs. For larger communities a power 

 pump, horse-drawn or motor driven, is 

 most efficient. 



Habits This is the caterpillar which 



and sometimes is so abundant in 



Damage, forests as to strip completely 

 the foliage of trees over hun- 

 dreds of square miles. In appearance, it 

 presents a blue head and it has silver 

 spots, diamond shaped, down the back. 

 The young caterpillars emerge from the 

 eggs when the leaf growth begins in the 

 early spring. They feed on the leaves and 

 may destroy all the foliage. They are to 

 be found in colonies on the trunk and 

 larger limbs, and are frequently seen 

 hanging by silken threads. Early in June 

 they leave the tree and take shelter under 

 stones, woodpiles, fences and other hiding 

 places, emerging early in July as moths. 

 The eggs are laid a little later, around 

 slender twigs. 



Remedies. When not destroyed by 

 their natural enemies, these 

 caterpillars must be given careful atten- 

 tion as soon as detected. The egg masses 

 on twigs may be hand picked and destroy- 

 ed or they may be daubed with creosote, 

 or sprayed with kerosene emulsion or 

 with one of the miscible oils of standard 

 make. Early spring spraying with lead 

 arsenate is effective, when done with 

 thoroughness. 



