Studies On Ecological Characteristics Of Orthaga Achatina Butler

This thesis is written to investigate and find out the ecological characteristics of the Orthaga achatina butler (Lepidotera: Pyralidae), known as a major insect pest on cinnamon(Cinnamomum camphora), throughout the laboratory experiment of raising and field study of their natural growth as follows:1.By raising the O. achatina with fresh leaves of cinnamon under seven different constant temperatures from 16, 19, 22, 25, 28, 31 to 34℃, the author found out that the exuviating interval, growing rate, death rate, egg laying amount and the period of ovipositing etc. varies evidently, which eventually leads to the variation of the trend index of their population. Their exuviating interval shortens with the rising of the temperature from 16 to 31℃and becomes longer at 30℃. The develop threshold goes up to the highest at the age of 1st and 2nd of larvae, while drops to the lowest as being pupae. The effective accumulated temperature rises to the highest when the pest remain pupae while falls down to the lowest when they are still in the eggs. The death rate of the eggs of the pest climb to the highest at 16℃, the lowest at 25, 28 and 31℃and becomes the highest again at 34℃... The lifespan of their adult shortens with the rising of the temperature; the amount of their ovipositing becomes the largest at 28℃and the trend index of population rises the highest at 28℃as well.2.Through the investigation of the pests'natural population under the different fields'of cinnamon, it was found out that the relationship between the average of their larvarium on each cinnamon and the time presents as a parabola. Meanwhile, the amount of the pest in the same larvarium is mainly related to its age, that is, the number of the pest increases when the larvae are young while decreases when they grow older, which has nothing to do with the growing condition of the cinnamon.3.When using trap lamp to trap the adult, the author found out that the eclosion varies among periods. The eclosion of the adult of overwintering generation reaches the peak during the first 10-day period of June, then comes their first and second generation of the eclosion from the middle ten days of August to that of September, which overlaps between two generations.4.By raising the pest collected from the wild field, the author also found out that there are 4 types of parasitic wasp, among which there is one type of Eulophidae, three types of Braconidae; and the parasitism appears very common among those types.