42 



CIRCULAR 2 7 0. U. S. DEPARTMENT OF AGRICULTURE 



about one-eighth of an inch long, grayish, flattened, with laeelike 

 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 sulfate (40 percent nicotine) 

 to 100 gallons of water, to which is added some soap or spreader. 

 The underside 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 blotchlike 

 mines in the leaf (fig. 49) 

 between the large veins 

 and causes the leaf to 

 become somewhat mis- 

 shapen. The adult in- 

 sect is a very small, 

 silvery moth which lays 

 eggs on the leaves. The 

 young worm burrows be- 

 tween the upper and 

 lower leaf surfaces, form- 

 ing the mine. When full 

 grown it pupates within 

 the mine, and the moth 

 emerges soon after. 

 There are probably two 

 broods in a season. In 

 the fall the worms make 

 silken bibernacula in the 

 mines, where they spend 

 the winter in the fallen 

 leaves. This pest is of 

 minor importance. Any 

 cleaning up or cultiva- 

 tion that destroys or 

 buries the leaves late in 

 the fall would prevent 

 many of the moths from 

 emerging the following 

 Figure 49. — Work of apple leaf miner in apple leaf, spring. 



Apple Fruit Miner 



The serpentine or apple fruit miner {Marmara pomonella Busck) 

 is more of a curiosity than a pest. The adult is a very small moth, the 

 young of which form winding whitish mines just under the skin of the 

 apple (fig. 50). The mines are also occasionally found on prunes. 

 This insect occurs so rarely that control measures are not necessary. 



