Occurrence And Damages Of Aleurodicus Dispersus Russell In Hainan Iland And Its Performance To Hosts

Previous distributions of Aleurodicus dispersus were limited to regions between tropical and subtropical zone. However, because of the frequent transmition of its host plants worldwidely A. dispersus has invaded rapidly every continent in the world except Antarctica, along with the frequent commercial trade of worldwide.Because of its wide host range and powerful reproductivity, A. dispersus has caused a serious economic loss of crop production in Hainan Island since it was first discovered in 2006. In this paper, biology and ecology of A. dispersus were studied systermatically. The major contents of this paper included the population dynamics and host plants of A. dispersus, effects of host plants on experimental population, and controling technique of A. dispersus in the field. The major results were as follows.In this paper, the host plants and population dynamics of A. dispersus were investigated. The results showed that the host of A. dispersus in Hainan Island include 175 species or varieties belong to 49 families, on 94 species of which belonging to 44 families A. disperses could finish a full generation and 81 species of which belonging to 41 families A. disperses could not finish a full generation. Most of the plants belonged to families Euphorbiaceae, Compositae, Leguminosa, Orchidaceae. There were 122 species or varieties belonging to 53 families were newly recorded species or varieties of host plants of A. disperses in Hainan Island, on most of them A. disperses could not finish a full generation. The occurrence degree of A. disperses was divided into three different grades according to the damage area caused by A. disperses. There were 31 species or varieties which belonged to the third grade. The population dynamics of A. disperses on guava, canna, pawpaw, Terminalia catappa, Ceris chinensis, Pterocarpus indicus were investigated in Hainan Island. The rusults indicated that A. disperses outbroke in antumn, the population of which started to development in middle and lately May, then outbroke from September to middle December.The studies of the effect of host transference on adaptation of A. disperses showed that A. disperses could improve the host performance dramatically since continuously feeding on particular host species, but the improving process was different among the host plants. With the host transference experiments, the improved host performance by continuously feeding on particular host species could not inherit, and the host performance would return to primary level as long as disappearing selection pressure.It was investigated that the development period, the life-span and livability of A. disperses on guava, canna, pawpaw and Pterocarpus indicus 4 host plants above in the incubators with 27±1℃and 70±5% relative humidity, and then the life table of the A. disperses was constructed. The results showed that the A. disperses had high survivorship and fecundity on these plants. However, it devoloped faster on guava, but slower on Pterocarpus indicus; it had the highest survivorship on canna but the lowest on pawpaw; it had the highest fecundity on canna but the lowest on Pterocarpus indicus.The experiments on the impact of yellow sticky traps (YST) to A. dispersus were made in guava fields. The results showed that the yellow sticky traps could catch more adults of A. disperses in the middle of the south than other three directions of guava tree canopy. And the largest amount of A. disperses adults trapped were obtained when the top of YST was kept at the same height of the bottom of guava tree canopy.