Damage, Biological Characteristics And Risk Analysis Of Ipomoea Cairica In Fuzhou District

Five-fingered morning glory (Ipomoea cairica (L.) Sweet) is a serious invasive weed. The distribution and damage of I.cairica have been surveyed for the first time in Fuzhou district. The results showed that I. cairica is wildly distributed in Fuzhou district. The main reason of wildly distribution of I.cairica in Fuzhou district is manmade introduction. The serious damage caused by I.cairica escaped to field in local region. The knowledge of I.cairica and recognition degree of damage caused by I.cairica are less for common people by questionnaire and interview.The surveys of growth of I.cairica in four different natural habitats were conducted. The results showed that I.cairica will rapidly grow in sunny habitats with ladder type consisted by shrub and tree. The life history characteristics and Growth characteristics of I.cairica were systematically studied during one and half year. The results showed overwintering phenomenon of I.cairica is usually not obvious in winter in Fuzhou district. Freeze injury of leaves was occurred in anomalous low temperature, but stem have strong growth ability. The seed of I.cairica didn't found in Fuzhou district, the results showed the spread of I.cairica is vegetative propagation.The disease and insect pest of I.cairica have been surveyed for the first time. Cassida circumdata and Leccoptera quadrimaculata are main insect pest,and will give some influence to growth of I.cairica. Colletotrichum gloeosporioides has been isolated from leaves , but low pathogenic ability have showed in inoculation experiment. Five species of pathogen nematodes have been collected from soil rhizosphere of I.cairica as follows: Helicotylenchus dihystera, Aphelenchus avenae, Helicotylenchus sp.,Aphelenchoides sp.),Filenchus sp. The results showed that few natural enemies is one of the main reasons of serious damage caused by I.cairica. The non-plant parasite nematodes with high population including 4 orders (Rhabditida,Monhysterida,Mononchida and Dorylaimida)were collected from soil rhizosphere of I.cairica. It's indicated that leave detritus of I.cairica is beneficial to development of populations of these nematodes.Risk analysis of I.cairica has been made according to situation of Fuzhou district. The suggestion of prevention and control , utilization of I.cairica are also provided.