40 CIRCULAR 270, U.S. DEPARTMENT OF AGRICULTURE 



the caterpillars are still small. The caterpillars may also be destroyed 

 in their webs by burning, as suggested for the tent caterpillar. This 

 may be done during the day. 



TUSSOCK MOTHS 



The rusty tussock moth (Notolophus antiqua L.) and the western 

 tussock moth (Hemerocampa vetusta Bdv.) are leaf -feeding insects 

 occurring chiefly west of the Cascade Mountains. The first-men- 

 tioned species passes the winter in the egg stage in dry leaves or on tree 

 trunks or twigs. The caterpillars appear in April and subsist mainly 

 on the foliage, but occasionally damage the fruit, and may be found 

 on a great variety of trees and shrubs. They feed for a month or more, 

 and when full grown are about 1 inch long, hairy, blackish or bluish, 

 with several thick tufts of hairs along the back. The male moth has 

 rusty brown wings, but the female is practically wingless and deposits 

 her eggs in a mass on the cocoon from which she emerged. A second 

 brood of caterpillars appears late in July and produces moths in 

 September; these in turn deposit the wintering eggs. The western 

 tussock moth has similar habits, except that there is but a single 

 brood each year, the eggs laid in July hatching the following spring. 

 Special control is seldom necessary, since sprays applied for other 

 leaf-feeding caterpillars keep these insects in check. Many of the egg 

 masses may be found and destroyed when the trees are pruned. 



APPLE LACE BUG 



The apple lace bug (Corythucha drakei Gibs.) is a pest of the apple 

 in Washington and Oregon. The young and adults feed on the lower 

 surface of the leaves, usually in groups. They dot the leaves with 

 black spots of excrement, and as the insects suck out the juices the 

 leaves become yellowed and eventually drop. The adult insect is 

 about one eighth inch long, grayish, flattened, with lacelike wings. 

 Eggs are deposited on the leaves, and there are probably two or more 

 generations annually. Fair control may be effected by using three- 

 fourths of a pint of nicotine sulphate (40 percent nicotine) to 100 gal- 

 lons of water, to which is added, some soap or spreader. The under- 

 side of the leaves must be thoroughly sprayed. 



APPLE LEAF MINER 



In western Oregon and in the Hood River Valley the apple leaf 

 miner (Phyllonorycter crataegella Clemens) may be found in apple 

 leaves and also in leaves of the wild hawthorn. It constructs blotch- 

 like mines in the leaf (fig. 49) between the large veins and causes the 

 leaf to become somewhat misshapen. The adult insect is a very 

 small, silvery moth which lays eggs on the leaves. The young worm 

 burrows between the upper and lower leaf surfaces, forming the mine. 

 When full grown it pupates within the mine, and the moth emerges 

 soon after. There are two or more broods in a season. In the fall 

 the worms make silken hibernacula in the mines, where they spend 

 the winter in the fallen leaves. This pest is of minor importance. 

 Any cleaning up or cultivation that destroys or buries the leaves late 

 in the fall would prevent many of the moths from emerging the fol- 

 lowing spring. 



