Aster albescens is a medicinal plant. The rust caused by Aecidium asterum is a new record in China and an importantdisease of A. albescens in Feng Tong-zhai national reservation area. The percentages of diseased plant...Aster albescens is a medicinal plant. The rust caused by Aecidium asterum is a new record in China and an importantdisease of A. albescens in Feng Tong-zhai national reservation area. The percentages of diseased plant and the diseasedleaf reach 100 and 28% respectively when the disease is serious. The disease results in leaf spot and leaf cast. Tuberculinapersicina is a natural hyperparasite of A. asterum and is firstly reported in the world. The hyperparasite attacks aecium ofA. asterum and hinderes the release of aeciospores. The symptom of the rust and the morphological characteristics of A.asterum is reported. The hyperparasitism of A. asterum and the morphological characteristics of the Tuberculina persicinaare also reported.展开更多
Tea tortrix, Homona coffearia Nietner (Lepidoptera: Tortricidae), is a seasonal pest of tea in Sri Lanka. Though it is active in dry weather, it is observed that populations do occur in wet weather causing serious dam...Tea tortrix, Homona coffearia Nietner (Lepidoptera: Tortricidae), is a seasonal pest of tea in Sri Lanka. Though it is active in dry weather, it is observed that populations do occur in wet weather causing serious damage to tea. The parasite, Macrocentrus homonae Nixon (Hymenoptera: Braconidae), controls the tortrix populations, but the efficiency of Macrocentrus has been reduced on account of hyperparasites in recent times. Level of hyperparasitism was studied in some tea tortrix prone areas in the up country region to study how this affected the tortrix populations during wet weather. The hyperparasitism varied during the study period of which average values observed ranged from 35% to 52% in the plantations studied. A negative linear relationship was observed between the average number of parasite cocoons in a cocoon mass and the percentage hyperparasitism. Three generations of tortrix were evident during the study period of May to November 2005. It is observed that tortrix populations do occur in dry and wet weather, and that hyperparasitism has been identified as the major cause affecting the efficient control of tortrix by the parasite. Possibilities of tea tortrix control in wet weather are discussed.展开更多
A hyperparasitic system with prolonged diapause for host is investigated. It is assumed that host prolonged diapause occur at larval stage, and parasitoid attack is limited to egg stage before the initiation of host d...A hyperparasitic system with prolonged diapause for host is investigated. It is assumed that host prolonged diapause occur at larval stage, and parasitoid attack is limited to egg stage before the initiation of host diapause. Such behavior has been reported for many ichneumons. Hyperparasite only attacks the parasitoids that parasitize the hosts. Hyperparasitic system is often used in biological control. The existence and stability of nonnegative fixed points are explored. Numerical simulations are carried out to explore the global dynamics of the system, which demonstrate appropriate prolonged diapause rate and appropriate intrinsic growth rate can stabilize the system. The reasons are explained according to the ecological perspective. Furthermore, many other complexities which include quasi-periodicity, period-doubling bifurcations leading to chaos, chaotic attractor, intermittent and supertransients are observed.展开更多
A hyperparasitic fungus was found on uredinia of Coleosporium plumeria on leaves of Plumeria rubra in Thailand.The hyperparasite was identified as Ramularia coleosporii following an examination of its morphological ch...A hyperparasitic fungus was found on uredinia of Coleosporium plumeria on leaves of Plumeria rubra in Thailand.The hyperparasite was identified as Ramularia coleosporii following an examination of its morphological characters and a phylogenetic analysis by using ITS sequence data.This is the first record of R.coleosporii on C.plumeriae in Thailand.Ramularia coleosporii has the potential for biocontrol management strategies of the rust.展开更多
基金This study was supported by the Natural Science Foun-dation of Sichuan Province of China(2003C006).
文摘Aster albescens is a medicinal plant. The rust caused by Aecidium asterum is a new record in China and an importantdisease of A. albescens in Feng Tong-zhai national reservation area. The percentages of diseased plant and the diseasedleaf reach 100 and 28% respectively when the disease is serious. The disease results in leaf spot and leaf cast. Tuberculinapersicina is a natural hyperparasite of A. asterum and is firstly reported in the world. The hyperparasite attacks aecium ofA. asterum and hinderes the release of aeciospores. The symptom of the rust and the morphological characteristics of A.asterum is reported. The hyperparasitism of A. asterum and the morphological characteristics of the Tuberculina persicinaare also reported.
文摘Tea tortrix, Homona coffearia Nietner (Lepidoptera: Tortricidae), is a seasonal pest of tea in Sri Lanka. Though it is active in dry weather, it is observed that populations do occur in wet weather causing serious damage to tea. The parasite, Macrocentrus homonae Nixon (Hymenoptera: Braconidae), controls the tortrix populations, but the efficiency of Macrocentrus has been reduced on account of hyperparasites in recent times. Level of hyperparasitism was studied in some tea tortrix prone areas in the up country region to study how this affected the tortrix populations during wet weather. The hyperparasitism varied during the study period of which average values observed ranged from 35% to 52% in the plantations studied. A negative linear relationship was observed between the average number of parasite cocoons in a cocoon mass and the percentage hyperparasitism. Three generations of tortrix were evident during the study period of May to November 2005. It is observed that tortrix populations do occur in dry and wet weather, and that hyperparasitism has been identified as the major cause affecting the efficient control of tortrix by the parasite. Possibilities of tea tortrix control in wet weather are discussed.
文摘A hyperparasitic system with prolonged diapause for host is investigated. It is assumed that host prolonged diapause occur at larval stage, and parasitoid attack is limited to egg stage before the initiation of host diapause. Such behavior has been reported for many ichneumons. Hyperparasite only attacks the parasitoids that parasitize the hosts. Hyperparasitic system is often used in biological control. The existence and stability of nonnegative fixed points are explored. Numerical simulations are carried out to explore the global dynamics of the system, which demonstrate appropriate prolonged diapause rate and appropriate intrinsic growth rate can stabilize the system. The reasons are explained according to the ecological perspective. Furthermore, many other complexities which include quasi-periodicity, period-doubling bifurcations leading to chaos, chaotic attractor, intermittent and supertransients are observed.
基金supported by the Natural Science Foundation of China(No.31600024)。
文摘A hyperparasitic fungus was found on uredinia of Coleosporium plumeria on leaves of Plumeria rubra in Thailand.The hyperparasite was identified as Ramularia coleosporii following an examination of its morphological characters and a phylogenetic analysis by using ITS sequence data.This is the first record of R.coleosporii on C.plumeriae in Thailand.Ramularia coleosporii has the potential for biocontrol management strategies of the rust.
