Electrophysiological Responses and Field Attractants of <i>Plutella xylostella</i> Adults to Volatiles from <i>Brassica oleracea</i>

The diamondback moth (DBM), <i><i>Plutella xylostella</i></i> (Lepidoptera: Plutellidae), is a major pest of crucifers. Many volatile compounds emitted by cruciferous vegetables are known to mediate the attraction of DBM adults to host plant and oviposition sites. However, development of highly effective attractants for DBM management is still needed. Here, we first analyzed the volatile compounds emitted by macerated broccoli leaves with gas chromatographic-electroantennographic detection and gas chromatography/mass spectrometry. Eight compounds, including benzaldehyde, limonene, phenylacetaldehyde, acetophenone, linalool, 2-phenylethyl alcohol, methyl salicylate, and methyl 2-methoxybenzoate, elicited robust responses from the antennae. Then, we conducted multiple field trapping experiments involving the "addition approach" (individually adding components to the most abundant component, <i>D</i>-limonene) and the "subtraction approach" to evaluate the attractiveness of different blends. We found that a 3-component blend of <i>D</i>-limonene, 2-phenylethyl alcohol, and methyl 2-methoxybenzoate (3:2:1) is the most effective attractant. This blend holds great potential for monitoring and management of <i><i>P. xylostella</i></i> populations.