ORCHARD CARE 149 



stronger than one-half pound of the paste to ten 

 gallons of water. 



The walnut caterpillar, Delano, integerrina, ap- 

 pears late in summer. The caterpillars with some- 

 what inky skin and white hairs work together in 

 large colonies upon the black walnut, butternut and 

 hickories. Sometimes when a small tree is attacked 

 the leaves are removed entirely and sometimes so 

 late in the season that the new growth following 

 their raids is winter-killed. In the north there is 

 only one brood, but in the southern states there are 

 two. Ordinary spraying with lead arsenate, three 

 pounds to fifty gallons of water, will destroy these 

 caterpillars. The species has one weak point which 

 allows of ready attack during the evening or in rainy 

 weather. The walnut caterpillar colony has the habit 

 of descending to some one limb and there resting in 

 a great mass in a loosely spun hammock weighing 

 several pounds, which may be removed by hand. 



A husk worm, larva of a fly not yet identified, 

 has proven injurious to the nuts of the black walnut 

 and the Persian and the Japanese walnut. The invo- 

 lucre turns dark before the nut is ripened and the 

 immature nut then falls to the ground. On break- 

 ing open the involucre a large number of small white 

 larvae are found to be at work. This pest will prove 

 to be serious unless we can learn the habits of the 

 species and find some weak points at which it may 

 be attacked. 



A number of species of the genus Acrobasis at- 



