See the section on Douglas-fir needle midge for suggestions on the design and timing of traps. The jar will contain other flying and crawling insects, so use a hand lens to help with identification. Place a moist towel inside the jar to catch the adult midges. As adults emerge from the soil, they fly towards the light (jar) to escape. Needle midge traps consist of a box with a jar inserted into the top edge of one side. (Photo by Jack DeAngelis, Living with Bugs.) Ground nests can pose hazards to shearing crews and visitors, so control is also beneficial for safety. Direct spraying of ground nests is allowed traps may be useful in finding these ground nests. There are currently no registered insecticides that may be used as toxic bait to eliminate the nest. Since the queen does not move outside the nest after this early period, later trapping only affects the worker population. Thus, early lure placement and trapping should help control some colony formation. The queen is the key to controlling population growth, and she only flies in March. Placing roughly 5 traps per 10 acres of field is sufficient for monitoring. Yellowjackets are the only Christmas tree “pest” for which there are specific chemical lures for attraction. They are useful for monitoring worker activity but not for control. These traps are less successful with German yellowjackets. Yellowjacket attractant traps include chemical lures, colors, and trap designs to attract western yellowjackets. (Photo courtesy of Oregon Department of Agriculture.)

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