66 



CIRCULAR 2 7 0. IT. >. DEPARTMENT OF AGRICULTURE 



FiGtiRE 74. — Stone fly feeding on peach bud. X 2. 



peach trees in the Pacific Northwest, and the reader is referred to page 

 53 for a discussion of this insect. 



Stoxe Flies 



Stone flies or salmon flies ( Tcu n iopteryx pacifica Banks) occasionally 

 injure the buds of peach, apricot, and plum trees in the spring (fig. 74 , 

 particularly where 

 these trees are grow- 

 ing near the Colum- 

 bia River or some 

 other large stream. 

 The young of these 

 insects lire in . the 

 s t r e a m s . and the 

 adult flies emerge 

 early in the spring, 

 when thousands of 

 east skins from which 

 the flies have emerged 

 may be found among 

 the rocks along the 

 stream banks. The 

 flies feed on the fruit buds mostly during warm, sunny weather, 

 destroying many of the buds and injuring others so that they produce 

 deformed fruit. If control is necessary, lead arsenate, in the propor- 

 tion of 2 pounds to 100 gallons of water, should be effective if applied 

 as soon as the insects appear. 



NUT INSECTS 



Filbert Worm 



The filbert worm 6 (Mdissojms laiiferreanus (Wals.)) is the most 

 serious pest of filberts in western Oregon and Washington on account 

 of its direct injury to the nuts. It is generally distributed through- 

 out the Pacific Northwest, but causes commercial loss only locally. 

 This worm is the larva of a pale to dusky moth having two coppery 

 bands near the tips of its forewings. Eggs are laid on the leaves 

 near the nuts, or on the husks, and the young worms enter the nuts 

 at the base. They mature after feeding for 3 or 4 weeks and leave 

 the nuts to overwinter in cocoons formed in the ground, in trash, 

 or in dried or rolled leaves on the ground. Pupation occurs from 

 early in May through August. Xo effective control measures have 

 been developed. 



Walnut Aphid 



The walnut aphid {Chronui'pkis juglandicola Kalt.) is the only 



insect pest of any importance on walnut trees in the Pacific North- 

 west. It is a small pale-yellow, wingless or winged insect found on 

 the underside of the leaves, often in considerable numbers. These 

 aphids secrete a sticky liquid known as honeydew, which covers 

 the leaves and nuts, and in which a black fungus grows. Syrphus 

 flies, ladybeetles, and other natural enemies of aphids (p. 67) usually 



: Also known as rhe Catalina eherrr moth. 



