Essential oils as spatial repellents for the brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae).
The brown marmorated stink bug (BMSB), Halyomorpha halys (Stål), native to Northeastern Asia, is a serious invasive pest in the United States, Canada, Switzerland, Germany and France. Several common essential oils and their compositions were tested against BMSBs as potential repellents. All the tested individual essential oils and a ternary oil blend showed significant repellency to both BMSB nymphs and adults. Clove oil, lemongrass oil, spearmint oil, ylang-ylang oil, and the ternary oil mixture (clove, lemongrass and spearmint) almost completely blocked attraction of BMSBs to the stink bug attractant-baited traps; whereas wintergreen oil, geranium oil, pennyroyal oil and rosemary oil resulted in 60-85% trap catch reductions. Over 20 BMSB antennally active compounds were identified from SPME headspace samples of the eight repellent essential oils using GC-EAD and GC-MS techniques. Among the synthetic EAD-active compounds tested in the field, eugenol, l-carvone, p/l-menthone, pulegone, methyl salicylate, trans/cis-citral, methyl benzoate and β-caryophyllene significantly reduced trap catches of BMSBs by 72-99%; these compounds are likely responsible for the repellency of their corresponding essential oils. Surprisingly, a synthetic mixture of the predacious spined soldier bug (SSB) [Podisus maculiventris (Say)] aggregation pheromone (trans-2-hexenal, α-terpineol and benzyl alcohol) also showed a significant inhibition of BMSB response to its attractants. These repellent essential oils and their active compounds, as well as the synthetic SSB pheromone, are potentially useful as part of an efficient, environmentally sound semiochemical-based IPM programme to combat this serious invasive stink bug.