Douglas-fir needle midge (Contarinia pseudotsugae, Diptera: Cecidomyiidae) is a native invasive species in Pacific Northwest Christmas tree farms, seed orchards, and nurseries where Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) is present. Douglas-fir needle midge (DFNM) causes discoloration and galls on the needles, thereby it affects the market value of the Christmas...