INSECTÐSYMBIONT INTERACTIONS Insect Associates of Ceratocystis albifundus and Patterns of Association in a Native Savanna Ecosystem in South Africa

Species of Ceratocystis Ellis and Halstead s.l. include important plant pathogens such as C. albifundusMorris, De Beer, and M. J. WingÞeld that causes a serious wilt disease of non-native, plantation-grown Acacia mearnsii De Wild. trees in Africa. The aim of this study was to identify the insects associatedwithC. albifundus in SouthAfrica and to consider themeans bywhich the pathogen spreads. Insects were collected weekly for 77 wk in a native ecosystem using modiÞed pitfall traps. Trapped insects were identiÞed, and fungi were isolated using carrot baiting and by plating them onto malt extract agar. Fungi were identiÞed using morphological characteristics and DNA sequence comparisons. Three different nitidulid (Coleoptera: Nitidulidae) beetles, Brachypeplus depressus Erichson, Carpophilus bisignatus Boheman, and Ca. hemipterus L, were collected, of which the most common were the Carpophilus spp. Two Ceratocystis spp., namely C. albifundus and C. oblonga R. N. Heath and JolandaRoux,were isolated fromall three insect species. Insect numbers and fungal isolates decreased signiÞcantly in the colder months of the year. Of the two Ceratocystis spp., C. oblonga was most abundant, occurring on 0.5% of the Carpophilus spp. C. albifunduswas isolated from 1.1% of the Brachypeplus individuals and from 0.01% of the Carpophilus individuals. This study presents the Þrst record of insects associated with C. albifundus and C. oblonga and provides an indication of environmental inßuences on fungal and insect populations, which could contribute to future disease management.