Sticky traps can be used to monitor the presence of adult fruit flies in cherry and apple orchards. The traps utilize both color and odor to attract the flies. It has been known for some time that the flies are attracted to the color yellow. Consequently, sticky board traps now used are colored yellow. The flies are also attracted to red and this color has been used on sticky spheres to monitor the apple maggot flies. Odor is the second stimulus. Household ammonia placed in bottles was a common attractant used in early sticky boards. The ammonia had to be changed frequently and the process was time-consuming. Today, the traps use Hy-Case Amino and ammonium acetate mixed into the sticky material on the traps. This attractant lasts several weeks under orchard conditions and lengthens the interval between trap changes to 2 to 3 weeks.