# Brown Rot Caused by _Gnomoniopsis smithogilvyi_ (syn.
## 2 _Gnomoniopsis smithlogilvyi_--Biology, Epidemiology, Symptomatology, and Identification  
_G. smithlogilvyi_ is an ascomycete with a wide distribution, occurring in several countries in Europe, Asia, Australia, and America [21; 22; 23]. It has been reported to exhibit diverse lifestyles as an endophyte, inhabiting different asymptomatic chestnut tree plant tissues,and as a pathogen, causing \"brown rot\" in fruits [22; 24; 25]. _G. smithogilvyi_ can also cause markers, as reported by [PERSON] and [PERSON] [26] in India, [PERSON] et al. [27] in the United Kingdom, [PERSON] et al. [28] in Spain, [PERSON] et al. [29] in Ireland, and [PERSON] et al. [30]. In fact, the bark canker caused by _G. smithogilvyi_ shows a symptomatology very similar to that caused by the chestnut blight pathogen _Cryphonoctra parasitica_, which is the causal agent of chestnut canker [31], but the severity may be distinct. _G. smithogilvyi_ has also been reported as a pathogen of several other species, affecting mainly nuts (hazelnuts (_Coryilus avellana_ L.), manna ash (_Frazinus ornus_ L.), holm oak (_Quercus llex_ L.), Turkey oak (_Quercus cerris_ L.), and maritime pine (_Pinus pinaster_ Aiton)), causing fruit rot, cankers, and necrosis in branches and leaves [18; 21; 22; 24; 25; 31; 32]. This fungus was initially identified independently by [PERSON] et al. [33] and [PERSON] et al. [21] as _G. smithogilvyi_ and _Gnomoniopsis castaneae_ (originally called _G. castanea_), respectively. However, morphological and phylogenetic analyses (based on DNA sequencing) showed the synonymy between the two taxons [34]. Currently, _G. smithogilvyi_ is the name adopted for this fungus [35]. Nevertheless, as stated by [PERSON] et al. [36], more data on the phylogeography of this fungus are needed. In fact, its origin and taxonomical features still remain unclear, causing debate about the possible existence of different lineages and the legitimate name of the species. The life cycle of _G. smithogilvyi_ and the process of how to infect chestnut have not yet been fully known. According to [PERSON] and [PERSON] [37], the primary infection is caused by ascospores that spend the winter on the infected plant debris lying on the soil surface of chestnut groves. During the flowering period, these ascospores are transported to flowers, leaves, and branches by wind and wind-driven rain and insects [22] (Figure 1). The fungus infects only the female part of the flower (pistil) through the stigma-style and not through the ovary wall [37]. The appearance of multiple embryos in the fruit, where one is rotted and the other healthy, suggests that the pellicle surrounding each embryo is impervious to the fungus [37]. Additionally, the infection of female flowers may also occur via _G. smithogilvyi_-infected pollen. The main means of entry into the other plant organs, such as branches and leaves, is through wounds caused by mechanical or natural injuries [26]. Ascomyc chestnut blossom infection is affected by several abiotic and biotic factors. The abiotic factors include temperature, rain, relative humidity, and wind. For example, an increase in temperature was reported to lead to a higher incidence of brown rot [38]. Likewise, [PERSON] et al. [39] found that the propagule deposition rate of the _G. smithogilvyi_ varies across seasons, being positively correlated with temperature, growing degree days at 0 and 5 \({}^{\circ}\)C thresholds, and wind gusts. Thus, it is expected that rising temperatures and strong winds due to climate change may increase the spread of the fungus in the future. This can be a problem because [PERSON] et al. [40] predict that precipitation and the maximum and minimum temperatures will increase during three future periods, namely, near (2015-2039), mid (2040-2069), and far future (2070-2100), which may increase the incidence of the disease. These authors even suggest which major crops should be grown in order to reduce the negative impact of future climate changes, suggesting that the adaptation strategies of the cropping systems must be considered.