Comparative stimulation of Scolytus multistriatus feeding by tested dihydroxybenzenes and benzaldehydes showed that molecules with 1,4 substitutions on the benzene ring were most active; 1,3 and 1,2 substitutions were progressively less active. Methoxyl substitution adjacent to the 4-hydroxyl group on benzaldehydes reduced feeding and replacement of a hydroxyl by a methoxyl group on 1,2 disubstituted phenols destroyed the feeding response. Methoxyl substitution on benzaldehydes increased volatility and short-range attraction, but reduced feeding activity in the laboratory bioassays.