Biology And Host Specificity Of Epiblema Tetragonana (Lepidoptera:Tortricidae) And Epinotia Ustulanan (Lepidoptera:Tortricidae)

Classical biological control through introduction of host-specific natural enemies from native regions has been going on for more than 100 years.Classical biological control has been focused worldwide for its target specific,self-sustaining,low benefit-costs and environmental friendly. Cases of successful classical biological control have been greatly inspired the passion of nations to undertake classical biological control works.Along with the development of theory and applied technology,classical biological control has became one of the important methods in the management of invasive plants.Understanding the insect's biology and host specificity is the first step in determining the potential for introduction of an insect to control invasive plants.Yellow Himalayan raspberry,Rubus ellipticus var. Obcordatus (Franch.) Focke (Rosaceae) is a serious invasive plant in the United States-Hawai'i which native to China. This study researched the biology and host specificity of Epiblema tetragonana (Lepidoptera: Tortricidae) and Epinotia ustulanan (Lepidoptera:Tortricidae) which are potential biological control agents for Yellow Himalayan raspberry.The main results are as follow:Adults of Epiblema tetragonana emerge in middle April.The first generation of adults emerge in the middle and late May.It passes through five generations in Yunnan province.Larvae live through the winter from October to April of later year.The averaged longevity of adults of Epiblema tetragonana is 5.6 d,and a generation is completed in 36.5 d at a temperature of 22℃to 26℃and a photoperiod of 14:8 (L:D) h.Egg production occurred 2 d after females eclosed from the pupal stage.The durations of the egg, larval,and pupal stages were 5.1,22.8 (five instars) and 8.2 d, respectively.Larvae of Epiblema tetragonana are able to complete development on 14 of 30 plant species in No-choice larvae feeding trials.Choice oviposition trials showed adults strongly preferred lying eggs on Rubus ellipticus var. Obcordatus over all other test plants.Field surveys further revealed that Rubus ellipticus var. Obcordatus was its only ecological hosts.Adults of Epinotia ustulanan emerge in the middle April.The first generation of adults emerge in the late May and early June.It passes through three generations in Yunnan province.Larvae lived through the winter from also from October to April of later year. The averaged longevity of adults of Epinotia ustulanan is 14.2 d,and a generation is completed in 55.5 d.Egg production occurred 5 d after females eclosed from the pupal stage.The durations of the egg, larval,and pupal stages were 9.1,26.6 (five instars), and14.6 d, respectively.Larvae of Epinotia ustulanan are able to complete development on 5 of 30 plant species in No-choice larvae feeding trials.Choice oviposition trials also showed adults strongly preferred lying eggs on Rubus ellipticus var. Obcordatus over all other test plants. Field surveys further revealed that Rubus ellipticus var. Obcordatuswas its only ecological hosts.The results of this study suggest that Epiblema tetragonana and Epinotia ustulanan are potential promising agents for control of Rubus ellipticus var. Obcordatus in the United States-Hawai'i, although additional host specificity tests and risk assessment should be completed.