ORCHARD INSECTS OF THE PACIFIC NORTHWEST 



73 



The level of the liquid should be maintained by adding water, and 

 the whole contents should be replaced every 10 days or 2 weeks. In 

 cool weather a small quantity of yeast should be added, as the bait is 



Figure 83. — Codling-moth bait in position in apple tree. 



more attractive when fermenting. Four or five of these baits scattered 

 about an orchard are sufficient. They should be examined daily 

 and the number of codling moths caught should be recorded. These 

 baits catch large numbers of moths, but it has not been demonstrated 



