Botryosphaeriaand Related Taxa Causing Oak Canker in Southwestern Spain

Abstract

Although root disease caused by Phytophthora cinnamomi is considered to be the most frequent and damaging disease associated with Quercus spp. decline in southwestern Spain, cankers commonly are observed on branches of declining Mediterranean Quercus spp. in this region. In surveys carried out in eight declining Quercus forests, strips of necrotic inner bark were common on diseased branches. Botryosphaeria stevensii, B. dothidea, and Diplodia sarmentorum consistently were isolated from these branches. Isolates of all three species caused cankers when inoculated onto excised Quercus branches. Inoculations on healthy branches in the field also induced canker development, but only B. stevensii caused lesions that girdled and killed the branches. The optimum temperature for in vitro growth of B. stevensii and B. dothidea was above 25°C, with slow growth at 35°C. In contrast, D. sarmentorum had an optimum temperature for growth of about 21°C, and did not grow at 35°C. The common occurrence and wide distribution of these pathogens, their association with cankers, and their ability to infect Quercus spp. suggest that they may contribute to the Quercus spp. decline in southwestern Spain.

Neofusicoccum parvum, a causal agent associated with cankers and decline of Norfolk Island pine in Australia

“…Environmental stresses include drought, extreme temperature fluctuations, nutrient deficiencies and mechanical injuries (Old and Davison 2000;Zhonghua et al 2001;Desprez-Loustau et al 2006;Slippers et al 2009;Dakin et al 2010). However, they can also be primary pathogens (Michailides 1991;Sánchez et al 2002Sánchez et al , 2003Savocchia et al 2007), especially when non-adapted hosts are exposed to an exotic pathogen (Denman et al 1999).…”

A spatial distribution model of cork oak (Quercus suber) in southwestern Spain: A suitable tool for reforestation

“…Other pathogens, such as Botryosphaeria, could also be contributors to the decline of Quercus spp. in southwestern Spain (Sánchez et al, 2003). The patterns and influence of global climate change remain uncertain, but oak disease caused by P. cinnamomi could be widely extended in the coming decades (Bergot et al, 2004).…”

Geographical and seasonal influences on the distribution of fungal endophytes in Laurus nobilis

“…Some Botryosphaeria spp. are well-known pathogens whose incidence increases after host stress, such as drought (Sanchez et al 2003). This effect could help to explain the greater recovery of B. sarmentorum in autumn.…”