NEW HAMPSHIRE COLLEGE 

 AND EXPERIMENT STATION. 



(Extension Press Bulletin No. 35.) 



TENT CATERPILLARS 

 By W. C. O'Kane. 



The common Apple Tree Tent Caterpil- 

 lar is a well-known pest in New Hampshire. 

 Practically every season it is found in 

 abundance at many points in the state. 

 The wild cherry sprouts which grow so 

 abundantly along the roadsides are one of 

 the favored food plants of this insect, and 

 serve as breeding places for it. 



The name tent caterpillar describes the 

 pest well. A colony of the caterpillars 

 make a conspicuous tent or nest in the 

 fork of a limb and use it for a shelter, 

 retiring to it in stormy weather or on 

 other occasions, and going out from it to 

 feed on nearby foliage. These tents are 

 conspicuous and remain on the trees long 

 after the caterpillars have reached full 

 growth and have deserted them. 



The adult of the apple tree tent cater- 

 pillar is a reddish brown moth with incon- 

 spicuous markings. It is on the wing in 

 the middle to the latter part of summer 

 and lays eggs in a compact, dark-colored 

 ring or mass around a twig, covering the 

 eggs with a glistening varnish. The egg- 

 mass remains unmatched on the twig until 

 the following spring. 



As soon as warm weather begins in the 

 spring, the eggs hatch and tiny dark, 

 hairy caterpillars soon begin feeding on 

 the opening buds. Shortly they begin 

 their tent or nest in a nearby fork. As 

 the foliage expands, the caterpillars eat 

 more and more of it, growing all the time. 

 At the same time they are constantly 

 enlarging their nest until, finally, when 

 they have reached full growth, about the 

 firs* of July, the tent may be as large as a 

 half-peck measure. 



The full-grown caterpillar is nearly or 

 quite two inches long. The general 

 color of its body is black. Down the 



middle of the back is a conspicuous white 

 stripe, and along each side is a row of blue 

 spots. 



The caterpillars then scatter from the 

 tree, finding any sheltered spot that they 

 can, and spin up cocoons. In these they 

 transform to a resting stage or pupa, and 

 later from this pupa the adult moth 

 emerges. There is one generation each 

 year. 



Control of this insect is not difficult. 

 The caterpillars are susceptible to poison 

 sprays and are rather easily killed by 

 spraying the foliage of the trees with 

 arsenate of lead, at the rate of three 

 pounds to fifty gallons of water. 



They may be destroyed when resting 

 on or in their tents by burning with a 

 torch. A convenient torch is made by 

 tying a bundle of rags on the end of a 

 pole and soaking them with kerosene. 

 Usually the caterpillars will be found on 

 the nest when it is cloudy or when the 

 weather is cool. 



THE FOREST TENT CATERPILLAR. 



We have in New Hampshire also an- 

 other and closely related insect known as 

 the Forest Tent Caterpillar, although it 

 does not make any nest or tent. These 

 caterpillars may be distinguished from the 

 species described above by the fact that 

 the head is blue in color and there is a 

 row of white diamond-shaped spots down 

 the middle of the back instead of a solid 

 stripe. 



The life-history of this species is similar 

 to that of the common tent caterpillar. 

 It is found on the trees early in the grow- 

 ing season. To some extent these cater- 

 pillars have a habit of collecting in masses 

 on the trunk of the tree. 



They attack many kinds of shade and 

 forest trees, as well as fruit trees. On 

 shade trees or fruit trees control is feasible 

 by spraying the foliage with arsenate of 

 lead, three pounds to fifty gallons of 

 water. On forest trees practical means of 

 control are wanting. Fortunately this 

 pest has not reached serious abundance 

 in recent years. 



Approved : 

 J. C. KENDALL, 



Director of Extension Work. 

 Durham, N. H., April, 1913. 



