30 



FARMERS BULLETIN 843. 



larva. The larvae upon hatching from eggs, which are deposited in 

 masses (fig. 35) on the underside of the leaves, feed at first only on 

 the underside of the leaflets,, but later they devour the entire foliage 

 except the stems and petioles. Small pecan trees, especially nur- 

 sery stock, sometimes are defoliated completely, and it is not uncom- 

 mon to see large branches on bearing trees stripped of their foliage. 

 The larvae feed in colonies (fig. 36), and in molting the larger 

 caterpillars invariably leave their feeding place and crawl to the 

 trunk or larger limbs, where in a mass they shed their skins, which 

 may adhere to the bark for several weeks or longer. After molting 

 they ascend the tree to continue their feeding depredations, and 

 when fully grown crawl down the trunk and immediately enter the 



soil to a depth of a 

 few inches. Here, 

 in a day or two, pu- 

 pation takes place. 

 In the North this 

 insect has only one 

 generation yearly, 

 but evidently at 

 least two genera- 

 tions occur in the 

 South. 



According to Bu- 

 reau of Entomology 

 records the moths 

 (see fig. 37) develop- 

 ing from overwin- 

 tering pup 83 emerge 

 from April 15 to 

 July 15, and shortly after emergence egg laying takes place on the 

 underside of the leaflets. The eggs, which are laid in masses usually 

 numbering from about 100 to 150 each, hatch in a little less than a 

 week and the larvae feed for 25 days or longer before completing their 

 growth. The caterpillars enter the soil to transform to brown pupa3, 

 in which state they remain about 18 days for the summer generation. 

 In the case of the fall generation the winter is passed as pupae (fig. 

 38) in the ground and the moths do not emerge until the following 

 spring or early summer. The second-brood larvae enter the soil 

 frpm the middle of September until the last week in October. 



CONTROL MEASURES. 



Whenever the egg masses or colonies of the caterpillars are dis- 

 covered they should be destroyed promptly. Growers often may 

 discover the larger larvae massed on the tree trunks in the act of 



FIG. 35, Tbe walnut caterpillar (Datana integerrima): Egg mass. En- 

 larged. 



