ORCHARD INSECTS OF THE PACIFIC NORTHWEST 49 



feeding, there is no satisfactory means of poisoning them. An 

 effective control measure can be employed only during the short 

 period when the flies are feeding on honeydew and other moisture 

 before laying their eggs. At this time a sweetened poison bait, sprayed 

 on the trees, very materially reduces the number of flies and conse- 

 quently the number of infested cherries. A formula that has given 

 satisfactory results in western Oregon is : 



Lead arsenate x /% pound. 



Molasses or sirup 2 quarts. 



Water 10 gallons. 



Any cheap molasses or sirup may be used, but honey should not be 

 used, as it attracts honeybees to the bait, and many of them may be 

 killed. This spray should be applied in the form of fine droplets to 

 the upper surface of the outer leaves, and seedling cherry trees and 

 foliage of other nearby trees should also be sprayed. It is not nec- 

 essary to spray the trees thoroughly, as the flies are active and will 

 find the bait readily. The fruit should not be sprayed any more than 

 necessary. In large orchards a power spray outfit may be used, and 

 it should be thoroughly cleaned out before the bait is put into it. 



Two or three applications of bait should be made at intervals of 

 about 1 week. If a heavy rain occurs shortly after the bait is put 

 on, the application should be repeated as soon as the trees are dry. 



The proper time to begin using this bait is early in June. Since 

 the time differs in different localities and in different seasons, local 

 authorities should be consulted about it. 



Pear Slug 



The pear slug (Caliroa cerasi (L.)) is sometimes called the cherry 

 slug, as it frequently skeletonizes the leaves of cherry trees. If it is 

 not controlled, the trees may be almost completely defoliated, as the 

 skeletonized leaves die and drop off. This condition seriously affects 

 the development of fruit buds for the following year's crop. The 

 slugs may be controlled on cherry trees in the same manner as on pear 

 trees. Control measures and the life history are given on page 43. 



Syneta Leaf Beetle 



The syneta leaf beetle (Syneta albida Lee.) is a very common pest 

 of the cherry west of the Cascade Mountains. It also attacks the 

 apple, pear, plum, prune, small fruits, and various shade and nut 

 trees. It is apparently a native insect that has found congenial 

 living conditions in cultivated orchards. The beetles injure the fruit 

 of the cherry when it is immature (fig. 57), eating patches of the skin 

 and parts of the flesh. This injury causes scars and deformities on 

 the mature fruit. The beetles also feed on the stems, causing some 

 of the fruit to drop, and on the buds, blossoms, and leaves. 



LIFE HISTORY 



The beetles emerge from the ground just before the trees begin to 

 bloom, usually appearing in considerable numbers during the first 

 warm days about that time. They are about one-fourth of an inch 



