ABSTRACT The black shank disease caused by Phytophthora nicotianae causes losses in tobacco crops up 100%. In Colombia, P. nicotianae populations are poorly known causing wrong diagnostics and erratic management. Amplification of the Ypt1 gene and morphological characteristics of colonies, sporangia, chlamydospores and hyphae were used to identify P. nicotianae isolates. Races were identified according to the reaction induced by each isolate on the differential tobacco varieties Hicks, L8, KY 14 x L8 and NC 1071. As results, 71 isolates of P. nicotianae were identified and classified by races. Colonies of P. nicotianae were of white color, cottony and fluffy texture with smooth, non-swollen hyphae; spherical papillae with an average of 1.26 μm and non-papillated and intercalary chlamydospores of medium size of 1.02 μm that are typical characteristics of P. nicotianae. A species-specific PCR-amplified band of 389 bp was detected in all isolates tested. The presence of races 0, 1 and 3 of P. nicotianae were determined in the Colombian departments of Huila and Santander. To the best of our knowledge, this is the first report of physiological races 0, 1 and 3 of P. nicotianae in Colombia. Results are of relevance for disease management and tobacco breeding.

RESUMEN Las enfermedades y los trastornos son una de las principales limitaciones de los cultivos de aguacate para la exportación y el mercado nacional. Sin embargo, estos factores limitantes son poco estudiados en países tropicales como Colombia. El objetivo de este trabajo fue evaluar un enfoque polifásico para el diagnóstico de patologías y trastornos asociados al aguacate cv. Hass en viveros y lotes en Antioquia, Colombia. Los resultados permitieron la identificación de varias enfermedades y trastornos presentes en diferentes tejidos en todas las etapas de desarrollo del cultivo. La enfermedad de la pudrición de la raíz se asoció a 10 microorganismos y dos trastornos abióticos. Diferentes órganos y tejidos de las plantas de aguacate fueron afectados por patógenos como Lasiodiplodia theobromae, Colletotrichum gloeosporioides sensu lato y Phytophthora palmivora. Se identiicaron patógenos no reportados previamente en Colombia como P. palmivora, Fusarium oxysporum sensu lato, Phytopythium vexans, Phomopsis sp. y Pythium cucurbitacearum. Por otra parte, se caracterizaron trastornos abióticos como hipoxia-anoxia, la atrofia de la raíz, las quemaduras en fruta por el sol y el daño por granizo. No se identificó la etiología del anillamiento del pedúnculo. El diagnóstico polifásico de patologías y trastornos es un enfoque apropiado como parte de un programa de manejo integrado de enfermedades en el cultivo de aguacate cv. Hass. Este trabajo es una herramienta de consulta en aspectos básicos asociados a la detección de desórdenes y patologías en aguacate y la taxonomía de los microorganismos implicados.

ABSTRACT Diseases and disorders are one of the main limitations of avocado crops for export and national markets. However, they are poorly studied in tropical countries such as Colombia. The objective of this research was to evaluate a polyphasic approach for the diagnosis of pathologies and disorders associated with avocado cv. Hass in nurseries and crop fields located in Antioquia, Colombia. Results allowed the identification of several diseases and disorders present on different tissues in all stages of plant development. The root rot disease was associated with 10 microorganisms and two abiotic disorders. Different organs and tissues of avocado plants were affected by pathogens such as Lasiodiplodia theobromae, Colletotrichum gloeosporioides sensu lato, and Phytophthora palmivora. Pathogens that had not been previously reported in Colombia were identiied, and among them P. palmivora, Fusarium oxysporum sensu lato, Phytopythium vexans, Phomopsis sp., and Pythium cucurbitacearum stand out. Abiotic disorders such as hypoxiaanoxia, root atrophy, fruit sunburn, and hailstorm damage were also identified. The etiology of peduncle ringing was not identified. Polyphasic diagnosis of pathologies and disorders is an appropriate approach as part of an integrated disease management program in avocado cv. Hass crop. This work is a reference tool on basic aspects associated with the detection of disorders and pathologies in avocado and the taxonomy of the microorganisms involved.

ABSTRACT Damping-off is considered one of the most serious risks for production of Pinus seedlings due to the significant losses it can cause in forest nurseries. In Colombia there is little information about the etiology of this limiting disease. Different species of the genus Fusarium have been reported as causal agents, which makes the study of the pathogenicity of this genus relevant. In this study, strain 001F of Fusarium oxysporum was obtained from the diseased tissues of P. patula seedlings. The identity of the species was determined by sequencing the internal transcribed spacer (ITS) regions. Pathogenicity tests confirmed the ability of strain 001F to cause damping-off symptoms in P. patula and P. tecunumanii. Thus, F. oxysporum strain 001F represents a significant risk to produce tree species in Colombia and in other parts of the world.

RESUMO O Maracujá roxo (Passiflora edulis f. edulis Sims, conhecido na Colômbia como gulupa) é uma cultura cada vez mais importante na Colômbia, como visto por um aumento da área de cultivo. Esta proeminência recente coincide com o baixo número de tecnologias existentes relacionadas ao cultivo da fruta, resultando em falta de conhecimento sobre seus patógenos associados e da ausência de testes de diagnóstico rápido e preciso. Com o objetivo de determinar a patogenicidade de microorganismos distintos isolados de amostras de maracujá roxo, alguns dos quais não tinham sido previamente relatados na Colômbia. A amostragem foi realizada em sete lotes localizados em duas regiões de Antioquia Colômbia. Através da utilização de sintomatologia campo, o isolamento de microorganismos, as características morfológicas, a análise molecular e testes de patogenicidade, a espécies de agentes patogénicos Phytophthora nicotianae var. parasitica, Colletotrichum gloeosporioides sensu lato e Phytophthora drechsleri foram identificados pela primeira vez na Colômbia. Estes causam lesões nos frutos, com uma incidência de 10,9, 7,6 e 2,8%, respectivamente. Este é também o primeiro relatório em nível global de Phytophthora drechsleri causando uma doença nesta espécie de planta.

ABSTRACT Purple passion fruit (Passiflora edulis f. edulis Sims, known in Colombia as “gulupa”) is an increasingly important crop in Colombia, as seen by an increase in the area under cultivation. This recent prominence coincides with a low number of existing technologies related to the cultivation of the fruit, resulting in a lack of knowledge about its associated pathogens and the absence of rapid and precise diagnostic tests. The objective of this study was to determine the pathogenicity of distinct microorganisms isolated from purple passion fruit samples, some of which had not been previously reported in Colombia. The sampling was performed in seven plots located in two regions of the Colombian Antioquia. With the use of field symptomatology, the isolation of microorganisms, morphological characteristics, molecular analysis, and pathogenicity tests, the pathogen species Phytophthora nicotianae var. parasitica, Colletotrichum gloeosporioides sensu lato, and Phytophthora drechsleri were identified for the first time in Colombia. These pathogens cause lesions in fruits, with an incidence of 10.9, 7.6, and 2.8%, respectively. This is also the first report on a global level of Phytophthora drechsleri causing a disease in this plant species.