IndexPlantation forestryEucalyptus plantationsChallenges for eucalyptus plantationsTeratosphaeria zuluensisOrigin and distributionBiology of Teratosphaeria zuluensisSymptoms of the diseaseObjective and aims of the researchForests are sinks and sinks of carbon permanently absorbed as their biomass constitutes 289 giga tons of carbon ( FAO, 2010). Tropical forests store 40% of all Earth's carbon, of which 58% is stored in the vegetation itself. According to the Global Forest Resource Assessment (FRA), in 2015 the global forest area was estimated at four billion hectares, equal to 30.6% of the world's total area (FAO, 2015). Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay Forest cover estimated by the FRA in 1990 was 4.13 billion hectares (31.6% of the world's land area). Deforestation is a crucial issue for the world's forests; however, the rate of annual forest loss slowed by more than 50% during 2010-2015 (3.3 million hectares per year) compared to 1990-2000 (7.3 million hectares). This is due to reduced forest loss in some countries and reforestation in others (FRA, 2015). Deforestation contributes heavily to global carbon emissions and is a major concern in the tropics. Land conversions and agricultural encroachment on forest are the main reasons for deforestation and biodiversity loss, especially in the tropics (Doumenge et al., 2012). It is important to protect forest resources as they mitigate climate change, serve as a potential source of bioenergy and protect biodiversity (Zomer et al., 2008). Plantation forestry To meet global subsistence and meet commercial demand for wood agricultural products, governments and landowners have relied on forestry plantations. The most recent survey by the Food and Agriculture Organization (FAO) estimated that plantations cover 7.0% of the global forest area (FAO, 2010). In Paraguay, investments in forest plantations have been surpassed in the last two decades, so plantation coverage has doubled since 1990 (FAO, 2010). In South Africa, the forestry industry relies exclusively on monocultures, particularly pine and eucalyptus species (Wingfield, 1997). As natural forest has become scarce or inaccessible, plantations are considered an alternative. Global forest plantation cover has increased 39-fold since 1965 to produce industrial roundwood, fuelwood, paperboard, wood-based panels and other non-timber forest products (Evans and Turnbull, FAO, 2010). Eucalyptus plantationsEucalyptus is the second major tree species, after pines, grown globally as plantation forests with a prime location in the Southern Hemisphere (Old et al., 2003). Eucalyptus species are a diverse genus of flowering trees and shrubs that belongs to the Myrtaceae family. One of the species Eucalyptus regnans is considered the tallest flowering plant known on earth (Commonwealth of Australia, 2017). There are over 500 species of eucalyptus worldwide and most are native to Australia (Damel, 2000). They are exceptionally unique to Australia as they have evolved under the harsh constraints of the Australian environment and have experienced selective pressure from their major parasites and diseases (Old et al., 2003). Their ability to grow quickly, easy propagation and adaptability to grow in difficult sites has led to large-scale eucalyptus plantings across theworld (Grossman, 2012). Challenges to Eucalyptus PlantationsEucalyptus plantations have expanded dramatically in the tropics, particularly in the Southern Hemisphere, over the course of the last hundred years. The nature of these plantations has been significantly modified following hybridization, selection, vegetative propagation, breeding and the introduction of other advanced techniques to improve the plant heritage (Wingfield et al., 2008). There is a vast range of pathogens that attack eucalyptus shoots, stems and leaves even in their native environment. However, their natural existence in heterogeneous forest communities and a broad genetic species base provide protection against disease outbreaks (Old et al., 2003). Identical clones prepared through tissue culture are grown on a large scale aiming for uniform growth and better quality. In such monocultures there is a high risk of epidemics that can destroy plantations on a larger scale. The risk has been increased internationally by the movement of germ plasm across countries, as seedlings or seeds may be infested with pathogens (CIFOR, 2003).Teratosphaeria zuluensisTeratosphaeria zuluensis was previously described as Coniothyrium zuluensis by MJ Wingfield. , Crous and TA Cout (Cortinas et al., 2006). It is one of the most significant pathogens causing stem canker of Eucalyptus species (Jimu et al., 2014). Eucalyptus stem canker is also known as Teratosphaeria canker or Coniothyrium canker; has emerged as a very harmful disease in eucalyptus plantations, especially in non-native regions (Jimu et al., 2014). For several years it was believed to be caused by a single pathogenic species. However, multigenic phylogenetic studies have led to the identification of other pathogenic species causing the same disease described as Colletogloeopsis gauchensis by MN Cortinas, MJ Wingfield and Crous in 2006 (Cortinas et al., 2006). Both fungal pathogens have undergone several name changes due to the application of new technologies and the currently accepted names are T. zuluensis and T. gauchensis (Jimu et al., 2014). Origin and distributionThe canker causing eucalyptus pathogen, T. zuluensis, was first discovered in 1988 in South Africa (Wingfield et al., 1996). Subsequently, the pathogen was reported from several countries on different continents including Mexico (Roux et al., 2002), Vietnam (Gezahgne et al., 2003), Malawi (Roux et al., 2005), China (Cortinas et al., 2006). ), Zambia (Chungu et al., 2010) and Uganda (Jimu et al., 2014). South Africa may be the origin of T. zuluensis as suggested by Wingfield et al. (1996), due to the fact that the pathogen is present in the countries where eucalyptus is distributed from South Africa (Wingfield et al., 1996). However, the origin of the pathogen is still unknown (Chen et al., 2011). Biology of Teratosphaeria zuluensisTeratosphaeria canker is a serious disease of eucalyptus that causes damage to the stems and branches of the tree (Wingfield et al., 1996). The disease is mainly caused by two different pathogenic species, T. zuluensis and T. gauchensis (MN Cortinas, MJ Wingfield and Crous, 2006). T. zuluensis is characterized by the development of isolated depressed lesions that often combine to form larger necrotic tumors on susceptible eucalyptus trees (Wingfield et al., 1997). Sometimes, lesions form in parallel cracks on the stem that give the cat's eye appearance, and pycnidia may appear on dead bark. The gum called kino exudes from cracks that stain the stem and branches of a susceptible tree (Wingfield et al., 1997). The disease can result in deformed branches and brush-like crowns, while severe infections inhibit growth and.