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.

Three new Leptographium spp. (Ophiostomatales) infecting hardwood trees in Norway and Poland

“…The other newly described Leptographium species, L. vulnerum and L. flavum colonized fresh lesions on tree stems. Wounds and cracks that may be caused by animals, wind, frost, silvicultural practices and various arthropods (Heath et al 2010 ), are essential entry points for ophiostomatoid fungi (Wingfield and Kemp 1993 ). However, despite the importance of ophiostomatoid fungi as possible serious tree pathogens, very little is known regarding the biodiversity of ophiostomatoid fungi associated with wounds on trees.…”

Ophiostomatales associated with wounds on hardwood trees in Poland

“…They colonize the plant tissues in and under the bark on the twig, branch or stem, and kill the area around wounds caused by animals, wind, frost, silvicultural practices (pruning and harvesting) and various arthropods. The success of infection depends mainly on the depth and condition of the wound (the wound must reach the sapwood and must be fresh) (Kuntz & Drake, ; Heath et al , ; Kamgan Nkuekam et al , ). The fungal propagules are transmitted to the wounds mainly through sap‐feeding beetles (Coleoptera: Nitidulidae) (Kamgan Nkuekam et al , ), wind (Wingfield et al , ) or silvicultural practices (Uzunovič et al , ).…”

Draft genome sequences of Diplodia sapinea, Ceratocystis manginecans, and Ceratocystis moniliformis

“…Species in the C. moniliformis complex are found on the surfaces of freshly wounded woody plants, especially trees ( Kile 1993 , Roux et al 2004 , Tarigan et al 2010 ). Interestingly this group of fungi are all saprobes ( Kile 1993 , Yuan & Mohammed 2002 , Tarigan et al 2010 ), unlike species in the C. fimbriata complex which includes serious pathogens of economically important plants ( Roux et al 2000 , Baker et al 2003 , Barnes et al 2003 , van Wyk et al 2007 , Heath et al 2009 ). In some cases, species in the C. moniliformis complex cause sapstain that can result in economic losses as they lower the value of timber ( van Wyk et al 2006 ).…”