Viroids are single-stranded, circular RNA molecules (234-406 nt) that infect a wide range of crop species and cause economic losses in agriculture worldwide. They are characterized by the existence of a population of sequence variants, attributed to the low fidelity of RNA polymerases involved in their transcription, resulting in high mutation rates. Therefore, these biological entities exist as quasispecies. This feature allows them to replicate within a wide range of host plants, both monocots and dicots. Viroid hosts include economically important crops such as tomato, citrus, and fruit trees such as peach and avocado. Given the high risk of introducing viroids to viroid disease-free countries, these pathogens have been quarantined globally. As discussed herein, Mexico represents a geographical landscape of viroids linked to their origin and comprises considerable biodiversity. The biological features of viroid species endemic to Mexico are highlighted in this communication. In addition, we report the phylogenetic relationships among viroid and viroid strains, their economic impact, geographical distribution, and epidemiological features, including a broad host range and possible long-distance, seed, or insect-mediated transmission. In summary, this review could be helpful for a better understanding of the biology of viroid diseases and future programs on control of movement and spread to avoid economic losses in agricultural industries.

Tomato brown rugose fruit virus (ToBRFV) has become a major threat to global tomato production due to its exceptional mechanical transmissibility and virion stability. Effective sanitation is essential for containment, yet the performance of commonly used disinfectants on greenhouse-relevant surfaces remains poorly characterized. This study evaluated multiple disinfectant formulations, applied by spraying or dipping, on polyethylene film, pruning shears, and human hands. After controlled inoculation with a standardized inoculum, treated surfaces were swabbed and extracts mechanically inoculated onto Nicotiana rustica L. Lesion number was visually quantified, and lesion area was measured using a computational image-analysis pipeline. Fifth-generation quaternary ammonium compounds (5°QAS) showed the highest virucidal activity on smooth, non-porous surfaces, reducing lesion numbers to fewer than 10 per leaf at 800–1000 ppm and maintaining infection severities below 1%. Glutaraldehyde at 500 ppm also performed strongly, achieving severities as low as 0.20% on plastic. Metallic pruning shears consistently retained infectious particles, with untreated controls exceeding 100 lesions per leaf and treated samples showing incomplete inactivation. Mechanical agents such as powdered milk and soap reduced infection but did not eliminate transmission. No clear dose–response trend was observed. The two most effective treatments, 5°QAS at 800–1000 ppm and glutaraldehyde at 500 ppm, significantly reduced or prevented systemic infection in tomato assays. These findings demonstrate that sanitation efficacy depends on formulation, surface type, and application method, providing operationally relevant guidelines for ToBRFV management.

Se realizaron aplicaciones de los inductores de resistencia: Messenger gold®, Virus Stop®, Actigard®, Virablock®, Kendal®, fosfito de potasio, Stymulus® Maxx, Bacillus subtilis y MC Cream® en el año 2018, de forma individual y combinados en secuencias, para evaluar su efecto sobre la concentración viral (densidad óptica), crecimiento, longitud de raíz, severidad, peso seco total, número y peso de frutos en el cultivo de jitomate (Solanum lycopersicum L.) infectado con Tobacco mosaic virus (TMV). La secuencia de los inductores Messenger gold®+ Messenger gold®+ MC Cream® + MC Cream® redujeron la concentración de TMV a los 38 días después de la inoculación, determinada mediante DAS-ELISA. La aspersión de Virablock® obtuvo la mayor altura promedio. Las plantas tratadas con la secuencia Virus Stop® + Virus Stop® + fosfito de potasio + fosfito de potasio obtuvieron la menor severidad promedio. Las plantas asperjadas con Messenger gold® + Messenger gold® + MC Cream® + MC Cream® registraron la mayor longitud de raíz, mayor peso seco total y el segundo mayor número y peso promedio de frutos que no mostraron síntomas de TMV en frutos.

En la zona productora de jamaica (Hibiscus sabdariffa L.) del estado de Guerrero en el ciclo otoño-invierno 2014 se observaron cinco parcelas con una incidencia de 90 a 100 % de plantas con aclaramiento de nervaduras, mosaico y amarillamiento. Se colectaron plantas asintomáticas y con los síntomas antes descritos y se injertaron en plantas sanas de jamaica observándose clorosis de venas y mosaico 17 días después en las plantas injertadas con hojas que mostraban síntomas. Se extrajo DNA y RNA de tejido de las plantas colectadas en campo y de las injertadas que mostraron síntomas y se analizó para fitoplasmas, begomovirus, virus de la familia Potyviridae y Okra mosaic virus (OkMV). Los resultados para fitoplasmas, virus de la familia Potyviridae y Okra mosaic virus fueron negativos. Sólo se tuvo el amplicón esperado en el caso de begomovirus. Las secuencias de ocho plantas con síntomas colectadas en campo tuvieron una similitud del 95 % con Okra yellow mosaic Mexico virus (OkYMMV). Dos plantas con síntomas colectadas en campo mostraron un porcentaje de similitud menor a otros begomovirus. Los resultados obtenidos indican que el amarillamiento de la jamaica está asociado a un complejo de begomovirus en el que se encuentra presente el OkYMMV.

En México existen más de 358 especies de plantas, de las que únicamente se consumen hojas y tallos tiernos, conocidas como ‘quelites’. Dado el potencial productivo, económico y nutrimental de estas especies, entre ellas la verdolaga, es preciso determinar factores que afecten su crecimiento y desarrollo. La verdolaga constituye una alternativa como hortaliza debido a su potencial nutrimental, productivo y económico; su rendimiento estará determinado principalmente por el desarrollo de tallos y hojas, por lo que el conocimiento generado sobre los factores que afectan su crecimiento resulta de gran importancia agronómica. En la presente investigación se evaluó el efecto de tres densidades de siembra en el crecimiento de la verdolaga. Se consideraron los datos correspondientes a tres etapas fenológicas del desarrollo de la verdolaga (desarrollo vegetativo, madurez vegetativa y floración) para determinar si existían diferencias significativas entre las medias de los tratamientos evaluados mediante un Anova y para determinar si existía homogeneidad de varianza se llevó a cabo el método Levene. Las plantas sembradas a una densidad de siembra alta (295 plantas m-1 lineal) tuvieron mayor altura, menor diámetro de tallo, menor número de hojas (grandes y chicas) y menor desarrollo de las ramas (longitud de ramas) en comparación con aquellas sembradas en densidades de siembra media y baja (250 y 134 plantas m-1 lineal); sin embargo, el número de hojas en las ramas depende del nivel del dosel donde éstas se localicen. La densidad de siembra es un factor que contribuye a determinar el crecimiento de la verdolaga ‘Chapingo”.

Tomato brown rugose fruit virus (ToBRFV) has rapidly become a major threat to global tomato production due to its exceptional mechanical transmissibility and remarkable virion stability. Effective sanitation is therefore central to containment, yet the performance of commonly used disinfectants on greenhouse-relevant surfaces remains poorly characterized. This study systematically evaluated the efficacy of multiple disinfectant formulations, applied either by spraying or dipping, on three surfaces central to greenhouse crop management: polyethylene film, pruning shears, and human hands. Following artificial contamination, treated surfaces were swabbed and the resulting extracts mechanically inoculated onto Nicotiana rustica. Lesion number was assessed through direct visual inspection, whereas lesion area was quantified via a computational image-analysis pipeline, enabling precise measurement of foliar infection severity. Generalized linear models and correlation analyses were implemented to quantify treatment effects and to evaluate consistency across surfaces and application methods. Fifth-generation quaternary ammonium compounds and glutaraldehyde exhibited the highest virucidal activity, but only on smooth, non-porous surfaces. In contrast, metallic pruning shears repeatedly retained infectious virions regardless of formulation or application method, identifying them as a persistent reservoir in greenhouse systems. Mechanical agents such as powdered milk and soap were partially protective but failed to achieve complete inactivation. No uniform dose–response trend was observed, consistent with a saturation-type effect where increasing concentration does not guarantee improved efficacy. The most effective treatments were validated in tomato transmission assays, confirming reduced or absent systemic infection. Together, these findings demonstrate that ToBRFV sanitation efficacy is determined by the interaction among chemical formulation, surface type, and application method, rather than dose alone, and provide experimentally grounded, operationally relevant guidelines for integrated ToBRFV management in protected horticulture.