| Bactrocera dorsalis（Hendel）is a kind of fruit and vegetable pest which originate from tropical and subtropical regions with widely-distributed host plants.So far,it seriously damaged Hylocereus undulatus（Britt）in its producing areas of Guangxi.Therefore,this research studied about population dynamics,overwintering characteristics,oviposition selection and host location of B.dorsalis in Nanning pitaya-producing areas.The purpose of the research was to provide a theoretical basis for Guangxi pitaya-producing how to predict and prevent scientifically.Mainly results were as followed:（1）In Xining village,Nachen town,Liangqing district,Nanning pitaya-producing area,from 2018 to 2019,the number of B.dorsalis male adults’growth and decline showed a single peak in all experimental orchards.The beginning period was in the first half of the April,and the trapping peak was from August to September.The trapping peak of B.dorsalis amount in passion fruit orchard,“Jidu1”pitaya orchard,“white cinnamon”pitaya orchard and“Puhong”pitaya orchard were from mid to late August.The trapping peak of B.dorsalis amount in citrus orchard,murcott orchard,“Taiwanese Dahong”orchard and mixed fruit orchard were from mid to late September,after that the trapping amount decreased gradually.From the second half of December to the third month of the following year was the final period of trapping.In Nalou town,Pumiao county,Yongning district,Nanning pitaya-producing area,from 2018 to 2019,the number of B.dorsalis male adults’growth and their decline also showed a single peak in all experimental orchard.In early August,the trapping peak of B.dorsalis was found in longan orchard.In lately August,the trapping peak of B.dorsalis was found in citrus orchard.The trapping peak of B.dorsalis in“Meilong6”orchard,“Meilong2”orchard,carambola orchard and lime orchard were found in mid to late September,after that the trapping amount decreased gradually.From the second half of December to the third month of the following year was the final period of trapping.According to host fruit-setting stage,the transfer regular of B.dorsalis in Xining village was as follows:January to March,citrus and murcott→April to May,passion fruit and mixed fruit（mango）→June to December,pitaya.The transfer regular of B.dorsalis in Zhenqi company and Pumiao town,was as follows:January to March,citrus and lime→April to May,mixed fruit（loquat）→June to August,longan（cracked）and pitaya→September to December,pitaya.Temperature was the main meteorological factor affecting the local population dynamics of B.dorsalis.（2）In pitaya-producing area in Nanning,B.dorsalis adults in winter could keep activity,and there was no phenomenon of overwintering in B.dorsalis.In pitaya orchard B.dorsalis’pupae were mainly distributed in 0～5 cm of the soil.There was no significant difference in pupation rate and eclosion rate in flat the and sloping grounds（P>0.05）.Therefore,B.dorsalis can pupate and feather in both flat the and sloping grounds.In citrus orchard B.dorsalis were mainly distributed in the soil layer between 0 cm and 5 cm,and there was no significant difference in the pupation and emergence rate between the tree crown and the root（P>0.05）.Therefore,B.dorsalis can pupate and feather at both crown and root of trees.（3）B.dorsalis had a significant oviposition preference in pitaya at different maturity in different varieties or same varieties.Female adults preferred to oviposit on the half-ripe of“Meilong2”and“Taiwanese Dahong”.They selected mainly fully-ripe and half-ripe among“Meilong6”,“White cinnamon zeal”,and“Puhong”,and there was a significant difference in the oviposition amount between fully-ripe,half-ripe and unripe（P<0.05）.The oviposition preference for B.dorsalis in different varieties with the same level of unripe was“White cinnamon zeal”>“Puhong”and“Taiwanese Dahong”>“Meilong2”>“Meilong6”;for half-ripe was“White cinnamon zeal”,“Puhong”>“Taiwanese Dahong”>“Meilong2”,“Meilong6”;for fully-ripe was“Puhong”>“Meilong2”,“White cinnamon zeal”>“Taiwanese Dahong”and“Meilong6”.The hardness of“Meilong6”,White cinnamon zeal”,“Puhong”and correctspoonding varieties’average oviposition amount was related（P<0.05）.The hardness of“Meilong2”,“Taiwanese Dahong”and correctspoonding varieties’average oviposition amount was not related（P>0.05）.（4）A total of 19 volatile substances could be mainly detected in the whole pitaya fruit.Shared substances in“Meilong2”,“Meilong6”,“Puhong”and“Taiwanese Dahong”were acetophenone,benzaldehyde,4-ethylacetophenone and methylacetophenone.α-Pinene was the specific volatile of“Meilong6”and（R）-（+）-limonene was the specific volatile of“Taiwanese Dahong”.GC-EAD showed thatα-Pinene,benzaldehyde,acetophenone,（R）-（+）-limonene,4-ethylacetophenone and 4-methylacetophenone were substances that caused the antennae reaction in both female and male without significant sex difference.Four-arm olfactometer research results showed that B.dorsalis female adults were tropismed by（R）-（+）-limonene,（+）-α-Pinene,acetophenone and benzaldehyde,while B.dorsalis male adults were tropism by（+）-α-Pinene,acetophenone,benzaldehyde,4-ethylacetophenone and 4-methylacetophenone.EAG research of B.dorsalis female showed that the most sensitive concentrations of（+）-α-Pinene,acetophenone,benzaldehyde,4-ethylacetophenone and methylacetophenone were from 10-2μg/ml to 10-3μg/ml,from 10-3μg/ml to 10-4μg/ml,10-3μg/ml,higher than 10-1μg/ml or equal to 10-1μg/ml,respecitively.EAG research of B.dorsalis male showed that the most sensitive concentrations of（+）-α-pinene,acetophenone and（R）-（+）-limonene was from 10-4μg/ml to10-5μg/ml,higher than 10-1μg/ml or equal to 10-1μg/ml,10-3μg/ml,respecitively. |
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