28 FARMERS' BULLETIN 841 



The full-grown larvae (fig. 34) usually measure an inch in length 

 and are covered with long white ana black hairs arising from numer- 

 ous tubercles. On reaching maturity they leave their webs and 

 transform to brown pupae in flimsy, hairy cocoons beneath rubbish 

 on the ground, under the scales of bark, or just under the surface of 

 loose soil. The earliest date for the emergence of moths of the second 

 brood is June 26, but most of the moths of this generation do not 

 appear until later. The second-brood larvae have been found desert- 

 ing their webs during the latter part of September, all through Octo- 

 ber, and occasionally as late as the first week in November, for the 



purpose of pupation. This 

 insect passes the winter as 

 pupae, and moths appear the 

 following year, during April 

 and May. 



CONTROL MEASURES. 



All webs containing cater- 

 pillars that can be reached 

 conveniently should be re- 

 moved and the larvae de- 

 stroyed. Sometimes burning 

 the webs on the trees will be 

 found practicable, but it 

 should be done carefully, so 

 that much of the foliage will 

 not be scorched. A long- 

 handled tree pruner can often 

 be used to advantage in re- 

 moving the webs that are 

 well up in the trees. When 

 the fall web worm is extremely 

 abundant, as is the case in 

 some years, the foregoing 

 measures can be effective to a limited degree only. Pecan orchards 

 sprayed for the pecan leaf case-bearer will suffer no material damage 

 from this insect, as the same treatment will destroy these cater- 

 pillars as well as several other leaf feeders. 



THE WALNUT CATERPILLARS 



In the South branches of large pecan trees often are defoliated 

 by colonies of a caterpillar which when full grown is black, with 

 long whitish hairs, and nearly 2 inches in length. This is the so- 

 called walnut, or pecan, caterpillar. When young it is brownish, 

 with white stripes and somewhat more hairy than the matured 



FIG. 32. The foil webworra (Hyphantria cunea): Moth 

 and egg mass. Enlarged. 



Datana integerrima G. & R. 



