Influence of monoterpene vapors on spruce spider mite,Oligonychus ununguis, adult females.

Adult female spruce spider mite,Oligonychus ununguis (Jacobi), were exposed to various concentrations of four host conifer monoterpene vapors (limonene,β-pinene,α-pinene, and Δ(3)-carene) for 24 hr to determine the lethal and sublethal effects. All four compounds were toxic to the mites. Further, at concentrations below the calculated LC50s, all four compounds decreased oviposition by the mites and three of the compounds (limonene,β-pinene, andα-pinene) influenced movement. WhereasO. ununguis populations may not normally be exposed to high concentrations of host monoterpenes, trees continuously emit some monoterpene vapors, and when trees are damaged or under stress, oleoresin may accumulate at points on the external surface of tree tissues thereby exposing mites to the influence of monoterpene vapors.