Behavioral Responses of Scolytus schevyrewi (Coleoptera: Curculionidae: Scolytinae) to Volatiles From Apricot Tree (Rosales: Rosaceae)

Abstract

Scolytus schevyrewi Semenov (Coleoptera: Curculionidae: Scolytinae) is native to China and Central Asia. Damage by the adults and larvae weakens local apricot trees (Armeniaca spp.), often causing death to many host trees. In previous studies, freshly cut apricot logs were found to be highly attractive to S. schevyrewi adults. To explore the possibility of trapping and monitoring this bark beetle, we evaluated the effect of the apricot tree volatiles on S. schevyrewi behavior. Volatiles from the apricot logs were collected by headspace sampling and subjected to coupled gas chromatography-electroantennographic detection (GC-EAD) analysis. Behavioral responses to EAD-active compounds were assessed using two-choice Y-tube olfactometers. The results showed that the antennae of females responded to 21 volatile compounds from apricot logs. Seventeen compounds were confirmed with authentic compounds. The Y-olfactometer bioassays showed that at a stimulation dose of 100 mu g, four compounds [(1S)-(-)-alpha-pinene, (+/-)-limonene, (1S)-(+)-3-carene, and 1-hexanol], and some binary mixtures of the four compounds [(1S)-(-)-alpha-pinene plus (+/-)-limonene; (1S)-(-)-alpha-pinene plus (1S)-(+)-3-carene; (1S)-(-)-alpha-pinene plus camphene; (1S)(-)-alpha-pinene plus (+/-)-limonene, (1S)-(+)-3-carene, and 1-hexanoll were significantly attractive to both sexes (except (+/-)-limonene and (1S)-(+)-3-carene for males), suggesting that these compounds may play a role in host tree selection by S. schevyrewi and should be evaluated as lures for population monitoring. In contrast, octanal, nonanal, decanal, linalool and N,N-diethylformamide appeared to repel S. schevyrewi adults inY-tube at the concentration tested.