First report of Phytopythium vexans causing the “Avocado sadness” in Michoacan, Mexico

Abstract

Mexico is the main producer, consumer and exporter of avocado in the world, being Michoacan the main producer state contributing more than 80% of the national production. There are phytopathogens that decimate the production causing the death of the tree. Root samples were collected in avocado trees that showed the characteristic symptomatology of the disease known as avocado sadness, the sampling was carried out in four of the main avocado producing towns, in the state of Michoacan, Mexico. The isolation consisted in sowing root tissue in Petri dishes with V8®-PARPH culture medium, subsequently they were identified morphologically and for species level it was determined by molecular biology, with the PCR-ITS technique. Pathogenicity tests were performed in triplicate with avocado seedlings with more than six leaves. After 24 hours, the inoculated plants expressed decay in the apical part, after 120 hours the leaves showed yellowing and after 15 days there was a generalized wilt on the stem and leaves, re-isolating the phytopathogen Phytopythium vexans. This study confirms the first report of the oomycete P. vexans affecting avocado trees in the most important producing region of the Mexican Republic.

Characterization and fungicides sensitivity of Phytophthora cinnamomi isolates causing avocado root rot in Zitácuaro, Michoacán

“…Este es el primer estudio de aislados de P. cinnamomi asociados con la marchitez del aguacate en la región oriente de Michoacán, que incluye el municipio de Zitácuaro. Otros estudios sobre esta enfermedad han reportado la presencia de P. cinnamomi en otras áreas del estado (Ochoa-Fuentes et al, 2007;Ochoa-Fuentes et al, 2018;Hernández-Pérez et al, 2019). La superficie cultivada de aguacate en on this disease have reported the presence of P. cinnamomi in other areas of the state (Ochoa-Fuentes et al, 2007;Ochoa-Fuentes et al, 2018;Hernández-Pérez et al, 2019).…”

“…Otros estudios sobre esta enfermedad han reportado la presencia de P. cinnamomi en otras áreas del estado (Ochoa-Fuentes et al, 2007;Ochoa-Fuentes et al, 2018;Hernández-Pérez et al, 2019). La superficie cultivada de aguacate en on this disease have reported the presence of P. cinnamomi in other areas of the state (Ochoa-Fuentes et al, 2007;Ochoa-Fuentes et al, 2018;Hernández-Pérez et al, 2019). The surface with avocado plantations in Zitácuaro has increased in recent years and could potentially be an important production area in the future.…”

“…En Michoacán, se reportó a Pythium sp. amazonianum y a P. vexans asociados a marchitez y a pudrición de raíz (Ochoa-Fuentes et al, 2018;Hernández-Pérez et al, 2019). Sin embargo, P. cinnamomi es el patógeno más frecuentemente asociado a la pudrición de raíz de aguacate, el cual generalmente, infecta raíces finas y alimentadoras por medio de zoosporas móviles (O'Gara et al, 2015;Rodríguez-Padrón et al, 2018).…”

“…Sin embargo, P. cinnamomi es el patógeno más frecuentemente asociado a la pudrición de raíz de aguacate, el cual generalmente, infecta raíces finas y alimentadoras por medio de zoosporas móviles (O'Gara et al, 2015;Rodríguez-Padrón et al, 2018). En el Mexican Journal of PHYTOPATHOLOGY Revista Mexicana de FITOPATOLOGÍA Advance online publication, 2021 P. vexans were reported as related to wilt and root rot (Ochoa-Fuentes et al, 2018;Hernández-Pérez et al, 2019). However, P. cinnamomi is the pathogen most frequently associated to root rot in avocado, and it generally infects fine and feeder roots using mobile zoospores (O'Gara et al, 2015;Rodríguez-Padrón et al, 2018).…”

Development of a Loop-Mediated Isothermal Amplification Method for the Rapid Detection of Phytopythium vexans

“…In China, P. vexans has been reported to cause diseases on ramie, tobacco, rubber trees, and dendrobium (Zeng et al, 2005;Tao et al, 2011;Bian et al, 2015;Yu et al, 2016). In addition, P. vexans can cause patch canker, damping-off, and crown rot, stem rot, and root rot in many economically important fruit trees, such as durian, kiwifruit, apple, and avocado in Vietnam, Turkey, Morocco, and Mexico, respectively (Polat et al, 2017;Hernández et al, 2019;Jabiri et al, 2020;Thao et al, 2020). The increasing reports of diseases caused by P. vexans suggest that this pathogen has the potential to cause large-scale disease outbreaks across multiple plants in the future.…”