The Study On Effects Of Asian Citrus Psyllid Host Plants Volatiles Mediated Host Selection

The Asian citrus psyllid, Diaphorina citri Kuwayama(Hemiptera: psyllidae) is the vector of Candidatus Liberibaeter asiatieu, Las and Candidatus Liberibaeter amerieanus,Lam. Its host plants both are rutaceae. The volatiles of host plants generally play a decisive role in the behavioral orientation of phytophagous insects to their host plants,which can make the insects apperceive the host at a far distance, so as to find suitable host plants. This paper we extracted the shoots volatile compounds from the six common host of the D. citri, including Murraya exotica L., Citrus reticulate Blanco, Citrus limon(L.) Burm.f., Citrus sinenssi L., Citrus maxima(Burm.) Merr. Cv. Shatian Yu., Clausena lansium(Lour.) Skeels. And studyed the effects of host plants on its selection behavior. We also studyed the biological activity of four common volatiles monomer to D. citri in laboratory conditions, expected can screened active compoundswhich can attract D. citri from rutaceae plants and then developed insect attractant, provided a new method for the integrated control of D. citri. The main results were as follows:(1) The taxis response of adult D. citri to the volatiles of host plants about Murraya exotica L., Citrus reticulate Blanco, Citrus limon(L.) Burm. f., Citrus sinenssi L., Citrus maxima(Burm.) Merr. Cv. Shatian Yu., Clausena lansium(Lour.) Skeels. Results show that D. citri both females and males showed a significant response to Murraya exotica L.,Citrus reticulate Blanco, Citrus limon(L.) Burm. f.,Citrus sinenssi L., selection rate both were above 70%, while have no significant response to Citrus maxima(Burm.) Merr. Cv.Shatian Yu., Clausena lansium(Lour.) Skeels.(2) Measured D. citri host searching behavior with observation in caged and wind tunnel experiment. Observation in caged results showed that in the first 2 h, D. citri females host selection rate of Murraya had a significant difference under the different light conditions, 4 h, 8 h and 24 h subsequently were not significant. D. citri males host selection rate were not significantly different in 24 h. The results of wind tunnel experiment showed that host foraging of D. citri is a slow process, D. citri finded host requires at least 15 minutes at the first time. The first time more than 50% D. citri finishedthe orientation behavior, entered halfway behavior and approximation behavior respectively were after 1.5 h, 2 h and 2.5 h. After 4 h D. citri landing on the Orange Jessamine were the most, however only 33.33% females and 28.33% males, D. citri landing on the wampee were the least, only 13.33% females and 12.07% males. In general, about half of the D. citri in accessible area will land on the host.(3) We extracted the shoots volatile compounds from Murraya exotica L., Citrus reticulate Blanco, Citrus limon(L.) Burm. f., Citrus sinenssi L., Citrus maxima(Burm.)Merr. Cv. Shatian Yu., Clausena lansium(Lour.) Skeels by using headspace solid phase micro-extraction method, then analyzed by gas chromatography/mass spectrometry(GC/MS) combined technology. The results showed that the six host plants shoots containing four common components, respectively were ?-caryophyllene, ?-caryophyllene,?-elemene and ?-ocimene. Jessamine(Murraya) which have strong attraction to D. citri mainly are vinyl compoun, esters and alcohols, respectively 43.79%, 10.74% and 5.94%.wampee(Clausena) mainly are vinyl compoun, esters, respectively 32.58% and 31.48%.Citrus mainly is vinyl compound, Navel Orange(52.74%), Eureka Lemon(64.71%),“ shatang ”(67.01%), orange Pomelo(82.64%).(4) The taxis responses of D. citri to six concentration of the four common volatile components ?-caryophyllene, ?-caryophyllene, ?-elemene and ?-ocimene were tested by using a four-armed olfactometer. The results showed that D. citri females were attracted strongly to the 1 ?L/m L ?-caryophyllene and 0.1 ?L/m L ? 10 ?L/m L ?-caryophyllene respectively, males were attracted strongly to the 0.001 ?L/m L ?-elemene, both females and males showed no significant response to ?-ocimene.This study defined the preference of D. citri to the six common rutaceae hosts, and proved the four common volatiles monomer can mediated D. citri host selection behavior in laboratory conditions. It is possible to develop attractant to control of D. citri.