ORCHARD INSECTS OF THE PACIFIC NORTHWEST 47 



CONTROL 



Thorough cultivation undoubtedly destroys some of the puparia 

 in the soil, but it does not reach enough of them to be of much value. 

 Since the maggots hatch within the fruit and are protected by it while 

 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. _' Y% 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. It is not necessary to spray the trees thoroughly, as the flies 

 are quite active and will find the bait readily. One or two pints is 

 sufficient for a tree, and more may be objectionable. The bait should 

 be put on the outer leaves, and 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 one 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 tbis bait is in June or early July. 

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

 local authorities should be consulted about it. 



PEAR SLUG 



The pear slug (Eriocampoides limacina Retz.) 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 41. 



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 about the time the trees are in 

 bloom, usually appearing in considerable numbers during the first 



