Factors influencing infection of Acacia mearnsii by the wilt pathogen Ceratocystis albifundus in South Africa

Abstract

It is well known that species of Ceratocystis, which cause canker and wilt diseases on trees, require wounds for infection. In this regard, a number of physical and environmental factors influence the success of wound colonization by these fungi. The aim of this study was to consider the influence of wound age, stem diameter and colonization of wounds by Ophiostoma quercus on the success of infection by Ceratocystis albifundus, an important wilt pathogen of Acacia mearnsii in southern and eastern Africa, under field conditions. This was performed by doing controlled inoculations on Acacia mearnsii trees, of different diameters, with C. albifundus at different time intervals after wounding and after pre-inoculation of wounds with O. quercus at the time of wounding. The success of infection by C. albifundus decreased significantly from 8 h after wounding and was higher on stems of greater diameter. Pre-infection of wounds by O. quercus reduced the infection success of C. albifundus. The overall results showed that managing wounds created during forestry operations by treating wounds with naturally occurring, non-virulent fungi, such as O. quercus, could reduce the prevalence of infections by C. albifundus.