Colletotrichum species causing cassava (Manihot esculenta Crantz) anthracnose in different eco-zones within the Recôncavo Region of Bahia, Brazil

Abstract

A survey to investigate the occurrence of cassava anthracnose disease (CAD) and distribution of Colletotrichum spp. in cassava plantations in different eco-zones of the Reconcavo Region in Bahia, Brazil, investigated during the rainy season of 2014. A total of 50 cassava fields distributed among 18 municipalities were visited and intensity of anthracnose evaluated. The highest disease incidence (DI) (83.3%) was in samples collected in São Félix, and the lowest (34.4%), in Varzedo. Municipalities that presented the highest values for DI were located within the 'Af' Köppen-Geiger eco-zone, also presenting the highest values for the estimated McKinney disease index. Based on previous studies of multilocus phylogeny, seven different species of Colletotrichum were identified (Colletotrichum fructicola, Colletotrichum tropicale, Colletotrichum gloeosporioides s.s, Colletotrichum theobromicola, Colletotrichum siamense, Colletotrichum brevisporum and Colletotrichum plurivorum) and a new approach based on ERIC-PCR was used aiming to group the 82 isolates according to these findings. The highest percentage of genetic variance (> 78%) was among isolates within fields. Based on the survey and genetic analysis, C. fructicola is probably the main causal agent of cassava anthracnose in the Recôncavo Region, since this species was present with highest incidence in all eco-zones, 47.61, 42.86 and 57.14% for Af (tropical rainforest climate), As (tropical dry savanna climate) and Aw (tropical wet savanna climate), respectively. This study is the first report of C. fructicola lineages as the most likely pathogen causing anthracnose disease of cassava in Brazil, and these findings may be used to guide the selection of resistant varieties.

Pest categorisation of Colletotrichum aenigma, C. alienum, C. perseae, C. siamense and C. theobromicola

“…No information exists in the literature on differences in aggressiveness among isolates of each of the five Colletotrichum species, although such differences have been reported for other species of the C. gloeosporioides complex (Wang et al, 2021). Liu et al, 2015;Diao et al, 2017;Sharma et al, 2017Sharma et al, , 2022de Silva et al, 2017b;Giblin et al, 2018;Chethana et al, 2019;Costa et al, 2019;Chaves et al, 2020;Chen et al, 2020;Chung et al, 2020;Mao et al, 2020;Yokosawa et al, 2020;Andrioli et al, 2021;Carbone et al, 2021;Luo et al, 2021;Moral et al, 2021;Oo et al, 2021;Han et al, 2022). However, these symptoms are similar to those caused by other Colletotrichum species belonging either to the C. gloeosporioides complex or to other Colletotrichum species complexes.…”

Pest categorisation of Colletotrichum plurivorum

“…Plants infected by C. plurivorum show symptoms of anthracnose, which include dark brown stem and fruit spots, stem cankers, pre‐ and post‐harvest fruit rot, leaf spots and wilt, shoot‐tip dieback and defoliation (Liu et al., 2019 ; de Oliveira et al., 2020 ). However, these symptoms are similar to those caused by other Colletotrichum species.…”

“…In the areas of its current distribution, C. plurivorum is reported to cause anthracnose on its host plants. Disease symptoms include dark brown stem and fruit spots, stem cankers, pre‐ and post‐harvest fruit rot, shoot‐tip dieback, leaf spots, wilting of leaves and defoliation (Liu et al., 2019 ; de Oliveira et al., 2020 ). Yield losses caused by C. plurivorum vary a lot.…”

MdWRKY71 promotes the susceptibility of apple to Glomerella leaf spot by controlling salicylic acid degradation

“…These can lead to more than 90% defoliation and diseased fruits in China, resulting in a decline in both the quantity and quality of fruit, while simultaneously compromising the overall vitality of apple trees (Shan et al., 2021 ; Zhang et al., 2016 ). Aetiological studies have identified several Colletotrichum species ( C. aenigma , C. alienum , C. fiorinae , C. fructicola , C. gloeosporioides , C. karstii , C. nymphaeae , C. siamense and C. tropicale ) as causal agents of GLS (de Oliveira et al., 2020 ; Sharma et al., 2017 ; Velho et al., 2019 ; Wang et al., 2015 ). C. fructicola is the predominant pathogen among the Colletotrichum species causing GLS in China (Velho et al., 2019 ; Wang et al., 2015 ).…”