Studies On The Developmental Biology And The Lethal Low Temperature In Oriental Fruit Fly Bactrocera Dorsalis And Melon Fruit Fly B. Cucurbitae

Both the oriental fruit fly Bactrocera dorsalis (Hendel) and the melon fruit fly Bactrocera cucurbitae (Coquillett) are quarantine pests which are classified to genus Bactrocera Macquar, family Tephritidae, order Diptera. The oviposition amounts, survival rates and the developmental durations of larvae were tested in detail at 26±1℃in the experiments of this thesis. And the lethal effects of low temperature to the two species of fruit fly feeded with artificial diet and Citrus reticulate respectively, were studied in these experiments. Results were as follows.1. The oviposition amounts of the oriental fruit fly and the melon fruit fly in one day were 137.3 eggs/25 female adults and 399.0 eggs/25 female adults respectively while they were lured by papaya. The survival rate of the oriental fruit fly and the melon fruit fly were 93% and 95% respectively. The means of weight of pupae of the oriental fruit fly and the melon fruit fly were 0.014g and 0.016g respectively. The rates of eclosion of the oriental fruit fly and the melon fruit fly were more than 86% and more than 90% respectively.2. The developmental durations of eggs,1st instar larvae,2nd instar larvae and 3rd instar larvae of the oriental fruit fly (are 2.5d,1d,2.5d and 8d respectively) were longer than those of the melon fruit fly (are 2d,1.5d,1.5d and 5d respectively) by means of artificial seeding. And also, the developmental durations of eggs,1st instar larvae,2nd instar larvae and 3rd instar larvae of the oriental fruit fly (are 2d,1.5d,1.5d and 7d respectively) were longer than those of the melon fruit fly (are 1.5d,2d,2.5d and 5d respectively) in natural conditons. The results revealed that the developmental duration of the oriental fruit fly in the immature stage in natural conditions was shorter than that in artificial conditions.On the other hand, the results revealed that the developmental duration of the melon fruit fly in the immature stage in natural conditions was longer than that in artificial conditions.3. The result of the experiment of the lethal low temperature to the oriental fruit fly eggs revealed that the lethal time were 8d and 11 d at 3℃and 5℃respectively. And the result of the experiment of hatchabilities at 14 different temperatures indicated that the lethal temperature to the oriental fruit fly eggs was 10℃.4. The result of the experiment of cold treatment on Nanfeng Orange (Citrus reticulata) vaccinated with eggs and larvae of the oriental fruit fly showed as follow. The oriental fruit fly eggs couldnot be hatched under 3℃for 7d. After 6d under 3℃, the incubated eggs couldnot be continued to larval stages. Larvae couldnot be pupated under 3℃after 7d. The oriental fruit fly eggs couldnot be eclosion under 5℃for 9d. After 7d under 3℃, the incubated eggs couldnot be continued to larval stages. Larvae couldnot be pupated under 5℃afterl2d.