Basic Research Of Environmental Friendly Control Of Rhagoletis Batava Obseuriosa (Diptera:Tephritidae)

Hippophae rhamnoides is an important tree species for soil and water conservation.It is also an important raw material for many medicine and health care products.Its fruit is rich in vitamins and other biological activitive substances,which have great economic value.Rhagoletis batava obseuriosa?RBO?is a main fruit borer of sea buckthorn.Its adult lay eggs under the fruit skin of Hippophae rhamnoides.The larvae hatch and eat up the fruit of the seabuckthorn,and leave only the outer peel and cause the victimize fruit lose the economic value.In severe cases,it can cause more than 90%loss of the total yield.Because the larvae lived in the fruit,and the pupated in the the earth,it's very difficult to control this pest.The traditional prevention and control measures are mainly by spraying organic chemical pesticides on the ground surface and tree crown.However,the over-used of organic pesticides often leads death of the natural enemies and the decrease of biological diversity.Moreover,excessive pesticide residues will bring a series of negative impacts on environment and human health.To develop environmental friendly control method,the author studied the pollution-free pesticides,the visual information and olfactory information of the RBO,and conducted preliminary researches on larval feeding,whic is to lay a foundation for mass rearing of parasitoid and the using of sterility techniques to control the RBO.1)Based on the principle of high efficiency,low toxicity,low residue and degradation,the author selected four pollution-free biological pesticides azadirachtinl,lambda-cyhalothrin,matrine and avermectinsthese,to study the contact lethal activity on the RBO adutls in the laboratory.The results of KT₅₀?median knockdown time?data analysis showed that male's contact toxicity of four pesticides was a little higher than that of female,for example,when the concentration of matrine is 0.005 mg/ml,the male's KT₅₀0 value is 39.21 h,less than the female's KT₅₀0 value of 56.13 h,but there was some exceptions,for example,when the concentration of matrine is 0.05 mg/ml,the male's KT₅₀0 value?15.76 h?is higher than the female's KT₅₀0 value of 12.39 h.Results of LC₅₀?median lethal dose?analysis showed that the contact toxicity of four pesticides to RBO was different.When adults were treated with12 hours,LC₅₀0 of four different pesticides were azadirachtin 7.737 mg/ml,lambda-cyhalothrin0.002 mg/ml,matrine 0.042 mg/ml and avermectins 0.008 mg/ml,respectively.The lethal effect of four pesticides from high to low were lambda-cyhalothrin,avermectins,matrine and azadirachtin;when adults were treated with 24 hours:LC₅₀0 of four pesticides were azadirachtin 6.963 mg/ml,lambda-cyhalothrin 0.001 mg/ml,matrine 0.008 mg/ml and avermectins 0 mg/ml,respectively.The lethal effects from high to low were avermectins,lambda-cyhalothrin,matrine and azadirachtin;when adults were treated with 48 hours:LC₅₀of four pesticides were azadirachtin 0.891 mg/ml,lambda-cyhalothrin 0 mg/ml,matrine 0.002mg/ml and avermectins 0 mg/ml,respectively.The lethal effects of four pesticides from high to low were avermectins,lambda-cyhalothrin,matrine and azadirachtin.The avermectins and lambda-cyhalothrin had high contact lethal effect to RBO adults,followed by matrine.The azadirachtin did not show effective contact lethal ability to RBO adults.More bioassay need to be carried to check their control effect of RBO in the field.2)The herbivorous insects can perceive the presence of host and non-host plants through their sensitive sense of smell,touch and taste,and move towards the host plant.At the same time,the insects have the ability to recognize the color,shape and size of objects in the process of host orientation.In order to explore the role of the RBO's vision in searching of the host,by setting up visual information of different colors,shapes and surface squres in the field,the author tested the oritational behavior of adutls.The experimental objects of different colors,shapes and surface areas were hung in the field.The tendency of RBO to the sphere with different colors but same sizes was firstly tested.The result showed that attraction from strong to weak was:orange>yellow>green>red>blue>purple.Among them,the number of RBO attracted by the orange sphere was the most,followed by the yellow and the green.The blue and the purple ball attracted the less.For the different surface area but the same color and shape,the large sphere attract significantly more RBO adult than small sphere did?t=10.562,df=10,P<0.05?.The larger surface area of the cube trapped more RBO adults,but there was no significant difference between the cubes?F=2.140,DF=5,54,P=0.074?.For the experiment of different shapes but with the same color and same surface area,the trapped number of RBO of four shapes were:cube>positive triangle>rectangular>sphere.However,there was no significant difference between four shapes?F=0.177,DF=3,34,P=0.912?.The results showed that the shape has no obviously effect on the trend of RBO.3)There is great relationship between the herbivorous insects and the host plants.The volatiles of the host plant play an important role between them.The fly insects mainly rely on the identification of the volatiles of the host to search and finally locate the host.In this study,the chemical constituents of the fruit and branches of H.rhamnoides were analyzed by GC-MS.Then,the electrophysiological reaction of RBO adults to the volatiles of the fruit and branches were detected by GC-EAD.The results of GC-MS analysis showed that the chemicals released by the fruit and the branches of the sea-buckthorn were ethyl hexanoate,l-caryophyllene,butyl isovalerate,etc.The results of GC-EAD test showed that there was an electrophysiological response to both ethyl hexanoate and l-caryophyllene.This result provided a theoretical basis for further understanding the relationship between the RBO and its host.At the same time,we could try to develop plant source attractant of RBO,which would be a more environmentally friendly way to control the RBO.4)Reference related fruit fly larvae in captivity formulation and technique,artificial breeding of seabuckthorn fruit fly larvae around are studied,in order to obtain suitable larval growth and development of artificial feed,provide theoretical guidance for the realization of the large-scale artificial breeding and reproduction.After two years of laboratory experiments,the larvae have been developed into pupae by the study of different composition ratios.