Chemical Communication Mechanism Between Apolygus Lucorum (Meyer-Dür) And Its Fall Host Plants Of Artemisia Spp.

Since1997, wide-scale adoption of transgenic Bt (Bacillus thuringiensis) cotton has effectivelycontrolled the cotton bollworm Helicoverpa armigera (Hübner), and subsequent reduction of insecticidesprays in Bt cotton has caused Apolygus lucorum (Meyer-Dür)(Hemiptera: Miridae) to be major insectpest on Bt cotton in China. Additionally, this species has become a key pest of Chinese dates, grapesand other crops. In this study, we conduct comprehensive field trials on population abundance of A.lucorum adults on different plant species in autumn during2010-2012, and study the chemicalcommunication mechanism betwwen A. lucorum and its fall host plants of Artemisia spp. The mainresults were summarized as follows.Population density of A. lucorum adults on different plant species shows obviously difference inautumn. During2010-2012, among119plant species tested, population density of A. lucorum adults onflowering Artemisia argyi Lévl. et Vant., Artemisia lavandulaefolia DC., Artemisia scoparia Waldst. etKit., Artemisia annua L. and Agastache rugosus (Fisch. et Meyer) O. kuntze. was markedly higher thanother many plant species in autumn. Further study on host preference of A. lucorum adults on threewide-distribution Artemisia spp.(A. argyi, A. lavandulaefolia, and A. annua) during different seasonsindicated that A. lucorum adults more prefer to three flowering Artemisia species over non-floweingperiods, and the average density of A. lucorum adults and standard attraction of three Artemisia speciesat flowering periods for this pest are extraordinary higher than non-flowering periods.In Y-tube olfactometer bioassays, The results indicated that A. lucorum adults significantly morepreferred to the direction of the olfactometer where flowering plants of three Artemisia species werepresent compared to control or non-flowering plants. Coupled gaschromatography-electroantennography (GC-EAD) revealed the presence of totally sixelectrophysiologically active volatile compounds from flowering plants of three Artemisia species.These were identified by using gas chromatography-mass spectrometer (GC-MS) as (Z)-3-hexen-1-ol,m-xylene, butyl acrylate, butyl propionate, butyl butyrate and (Z)-3-hexenyl acetate. However, A.lucorum of both sexes only exhibited a significantly behavioral response to m-xylene, butyl acrylate,butyl propionate, butyl butyrate. Furthermore, the results obtained from sticky traps and bucket-shapedtraps showed that m-xylene, butyl acrylate, butyl propionate and butyl butyrate captured more A.lucorum adults than control in the field during2011-2012. Moreover, the bucket-shaped traps alsorevealed that the trap effect of each volatile was no difference in gender. In addition, the comparativestudy of two trap pattern found that bucket-shaped traps may be more appropriate for field attraction ofA. lucorum adults.Additionally, by use of GC-EAD and GC-MS, further study indicated that, active compoundsidentified from early-season host plants (Ziziphus jujuba Mill., Vitis vinifera L., Vicia faba L. andChrysanthemum coronarium L.) and summer host plants (Helianthus annuus L., Humulus scandens(Lour.) Merr., Ocimum basilicum L. and Agastache rugosus (Fisch. et Meyer) O. kuntze.) that can elicit female and male A. lucorum adults electroantennogram (EAG) responses were basically the same asthose identified from three flowering Artemisia plant species. Therefore, active compounds emittedfrom autumn Artemisia spp. play an important role in the host location of A. lucorum for early-seasonand summer host plants.Among186plant volatiles evaluated in the field in2011, there are totally17plant volatiles displaybetter trap effect to A. lucorum adults, that are α-farnesene, α-humulene, α-pinene, ethyl butyrate,propionic acid isobutyl ester, hexyl acrylate, borneol,3-cyclohexene-1-methanol,(-)-terpinen-4-ol,nonanal, decanal,3,4-dimethylacetophenone,3-propyltoluene, tetradecane,(1S)-(-)-camphor,(±)-camphor and (+)-camphor.Our results provide groundwork for analysing the patterns of host plant use of polyphagous insectpest such as A. lucorum, and construction of integrated pest management of this pest. Additionally,research on chemical communication mechanism between A. lucorum and its fall host plants ofArtemisia spp., as well as function of active compounds emitted from autumn Artemisia spp. play in thehost location of A. lucorum for early-season and summer host plants shed light on overall analysing therelationship between A. lucorum and its hosts, clarification of host switching of A. lucorum duringdifferent seasons, and the development of environmentally sound and sustainable management tactics ofthis polyphagous mirid bug.