This species is best known as a primary pathogen on kiwifruit (Actinidia deliciosa) in Rio Grande do Sul and Santa Catarina, Brazil (Ferreiraet al. 2017; Oliveira et al. 2021; Piveta et al. 2016). However, Actinidia appears to be highly susceptible to Ceratocystis species, and isolates of C. manginecans (Eucalyptus-type strains) and the following new specieswere also associated with Ceratocystis wilt on kiwifruitand shown to be pathogenic to this host (Ferreira et al.2017; Oliveira et al. 2021; Piveta et al. 2016). Variation in microsatellite markers suggested that the C. alfenasii population on Actinidia in Rio Grande do Sul was native to the area (Ferreira et al. 2017). Ceratocystis alfenasii also causes a wilt on yerba mate trees (Ilex paraguariensis) in plantations in Rio Grande do Suland Paraná (Brito et al. 2021; Santos et al. 2018). Melo et al. (2016) reported the fungus causing blackrot in corms of yellow potato (Arracacia xanthorhiza) in Minas Gerais. Isolates from these three unrelatedhosts were interfertile in crossing studies (TABLE 2), and they grouped closely in the phylogenetic analysis of MAT sequences, which placed C. alfenasii outside of the South American and Caribbean subclades of the LAC (FIG. 1). No distinguishing morphological features were noted in C. alfenasii isolates compared with other LAC species.

BRAZIL. RIO GRANDE DO SUL:Farroupilha, from Actinidia deliciosa, Jul 2010,G. Piveta (holotype ISC 455943). Ex-type culture URMICRO 11731 = C3666 = PM20.

This species appears to be native to the Atlantic coastal region of Brazil from Rio de Janeiro state to Rio Grande do Sul. It has a broad host range,but it has been most commonly collected from black-rotted corms of Colocasia esculenta found in grocerystores, markets, and distribution centers in Brazil(Harrington et al. 2005, 2011; Oliveira et al. 2018).Inoculation studies suggest that Colocasia isolates aremore aggressive on Araceae than are other Ceratocystis isolates from Brazil (Thorpe et al. 2005). Ceratocystis atlantica also causes a wilt on Mangifera and Annonasquamosa in northeastern Rio de Janeiro state (Bakeret al. 2003; Oliveira et al. 2015b; Silveira et al. 2006). This species and the very closely related C. manginecans sensu lato are the only Ceratocystis species causing wiltand mortality of Mangifera, but C. manginecans has been much more widely distributed in Brazil (notably São Paulo) and internationally (Oliveira et al. 2015b). C. atlantica was reported on Actinidia from one farm in Rio Grande do Sul (Ferreira et al. 2017) and on Eucalyptus in Paraná, although it is not clear how common or important this species is on Eucalyptus. The tested isolates of C. atlantica from the above hosts were interfertile with the C. atlantica MAT1 tester strainfrom Mangifera (TABLE 2), and they formed a monophyletic group closely related to C. manginecans and C. fimbriata using MAT sequences(FIG. 1). Like C. manginecans, C. atlantica shows substantial variation in ITS sequences due to numerouslinked indels (FIG. 2).

BRAZIL. RIO DE JANEIRO: City of Riode Janeiro, from Colocasia esculenta, Oct 2001,T. Harrington (holotype ISC 455944). Ex-type culture CBS 114713 = URMICRO 11730 = C1865.

The type species for the genus is now restricted to a widely distributed strain that causes a black rot ofsweet potato, Ipomoea batatas. Our isolate C1421(CBS 114723, dried specimen BPI 843729; TABLE 1)from North Carolina, USA, was designated as the ex-epitype culture (Marincowitz et al. 2020). The Ipomoea strain is uniquely pathogenic to Ipomoea and has very limited genetic variation across its known range in eastern USA, Hawaii, New Zealand,and Asia (Engelbrecht and Harrington 2005; Li et al.2016). The disease was first recognized in the eastern USA, with symptoms of the disease reported in themid-1800s (Li et al. 2016), but the pathogen is most closely related to Ecuadorian strains of Ceratocystis from Theobroma, Schizolobium, and Hevea (FIG. 1)and to C. fimbriatomima, which was described from Venezuela (Van Wyk et al. 2009). In general, female mating testers of the Ipomoea strain do not cross well with other isolates, and the isolates from Ecuador did not cross with the Ipomoea tester strain (TABLE 2)