Tree health in South Africa: Retrospect and prospect

Abstract

South Africa is a country with very limited natural forest cover. Consequently, the timber and fibre needs of the country cannot be provided for from indigenous forest. It is largely for this reason that South Africa initially developed a highly productive plantation forest industry, which today makes a substantial contribution to the local economy. These plantations are based on non-native species of Eucalyptus, Pinus and Australian Acacia. In the early years of establishment, South African plantations were relatively free of pest and pathogen problems. But, over time, an increasing number of insects, fungi and bacteria have emerged as serious threats to the sustainability of the forestry industry. Numerous native pests and pathogens, especially insects, have adapted to these introduced tree species to cause damage or disease. The problem is compounded by the accidental introduction of non-native pests and pathogens, and this has been at a rapidly increasing rate over the past three decades. Some of these introduced pests and pathogens also threaten the fitness and even the survival of many indigenous South African tree species. Fortunately, South Africa has developed an impressive knowledge base and range of integrated management options to deal with these problems. This development was first driven by government programmes, and in more recent years by public–private partnerships between industry, universities and government. It is clear from the pattern of emergence of pests and pathogens in recent years that South Africa will deal with an increasing number of these problems and a continuously changing tree health environment. This requires robust investment in both quarantine and mitigation mechanisms to protect the country’s biodiversity as well as to ensure the sustainability of its wood and fibre industries.

Biogeography and global flows of 100 major alien fungal and fungus‐like oomycete pathogens

“…Biological invasions, that is the human‐mediated introduction of organisms beyond their native range, can lead to changes in the key factors of the disease triangle. For example, they can enable new associations between pathogens and naïve hosts, and consequently result in emerging infectious diseases (EID) (Anderson et al., 2004; Ogden et al., 2019; Wingfield et al., 2010). Besides being caused by invasive alien taxa (i.e.…”

Botryosphaeriaceae diversity on Eucalyptus clones in different climate zones of Indonesia

“…However, when infected hosts are subjected to stressful conditions such as drought, frost or insect feeding, they can result in severe damage (Mehl et al, 2013; Slippers & Wingfield, 2007). One common form of stress associated with Botryosphaeriaceae infections is the movement of plants to novel environments where they are subjected to insect and pathogen damage, not typical of their natural environments (Burgess et al, 2016; Wingfield et al, 2010). For example, various Botryosphaeriaceae species are known to cause serious diseases on Eucalyptus when trees are established in non‐native environments such as in South Africa and South America (Pavlic‐Zupanc et al, 2017; Pérez et al, 2009; Slippers et al, 2004; Wingfield et al, 2015).…”