Primary Research Of Biological Characteristics And Attractants Of Rhagoletis Batava Obseuriosa(Diptera: Tephritidae) In The West Of Inner Mongolia

Hippophae rhamnoides distributes in many provinces in Northern China and has functioned as a soil and water conservation tree specie.This tree species also has economic values on Chinese Medicine and health care.The seabuckthorn fruit fly,Rhagoletis batava obseuriosa(Diptera: Tephritidae)(RBO),is a serious fruit borer of H.rhamnoides,and has caused heavy economic losses to local farmer.The life cycle and biological characteristics of RBO,including eclosion,mating,oviposition,pupation and population dynamics were studied through laboratory and field observation in Dengkou county,Inner Mongolia.The results showed that about 81.3% of RBO emerged from the time 6:00 to 10:00,and the peak time was 8:00 to 9:00.The larvae came out of fruit and pupated mainly in the early morning from 0:00 to 6:00,especially from 3:00 to 6:00.The mating time mainly occurred in the day time and there were two peak times from 12:00 to 13:00 and from 16:00 to 17:00.Usually,the mating lasts 239 ± 11.86(SE)min.The fruit fly preferred to lay one egg into one fruit which the length was 6.97 ± 0.28(SD)mm and the width was 5.37 ± 0.40(SD)mm.The mating and egg laying behavior of RBO were studied in details too.There was only one generation annually in Dengkou.The adults of RBO occurred from the middle June to the early August,and weather could have impact on adult trapping.The adult occurrence could be divided into the beginning occurrence periods,full incidence beginning periods,peak periods,terminal periods and end periods.The population density is higher in the full incidence beginning periods,peak periods and terminal periods.More male adults trapped in the beginning occurrence periods,but more females could trapped in the following periods.The adults without food supply could only live 2~4 d.The lifetime of RBO could extend significantly by feeding artificial diets(F = 129.911;df = 7;P < 0.01).The adult lifetimes changed with different diets and the longest lifetime was B diet(14.04 ± 7.50 d,SD)and the shortest lifetime was A diet(9.54 ± 5.38 d,SD).There were no significant difference on adult lifetime between male and female.The fecundity of flies fed by different artificial diets had no significant difference(F = 0.701;df = 5;P > 0.05).Seabuckthorn fruit flies have a preference for landing on the yellow,orange and green fruit simulators to rest or lay eggs.The flies also have a strong tropism to damaged fruits.There was no difference on amount of eggs laid on fruits of Hippophae rhamnoides and Nitraria tanggutorum.To control the flies with attractants is an important thchniques in the Intergraed Pest Managements.In this study,five efficacious lures of seabuckthorn fruit flies were obtained by screening the well known flies attractants.The attractive ability of different attractant were: lure TQ > lure T > lure Y > lure L > lure LQ.The numbers of seabuckthorn fruit flies trapped by different attractants were 670.50 ± 73.48(SE),593.69 ± 72.50(SE),446.00 ± 54.57(SE),334.58 ± 43.25(SE)and 270.04 ± 38.01(SE),respectively.Lure TQ,lure T and lure Y attracted both male and female adults.The attractive effectiveness of lure T,lure Y and lure LQ lasted only 2 days,while lure TQ and lure L could last longer.The effective distance of lure Y is less than 100 meters.More flies were trapped in the understory layers of host tree.All three forms of lure L could attract seabuckthorn fruit flies,and have no significant difference.The attractive effect of the mixture of lure Y and lure T were better than only lure Y.The attractive effect of A(lure Y : lure T = 2:1),B(lure Y : lure T = 1:1)and C(lure Y : lure T = 1:2)increased successively.But there were no significant difference of flies trapped by that three mixtures and lure T separately(F = 0.731;df = 3;P > 0.05).The attract-and-kill system has the advantages of high-effect,environmental friendly and economic,therefore,incorporated with biopesticide against seabuckthorn fruit fly would have great potential in practice.However,the lures can not last longer in the fields.Thus,our research group has begun to use the embedding technology to prolong the holding period of these attractants.Morover,in order to better use the semiochemicals controlling the R.batava obseuriosa,the extraction,identification and field bioassay of the host marking pheromone,host plant volatiles and sex pheromone of seabuckthorn fruit fly are under researched in our laboratory.