scholarly journals Capacidad de infección de hongos asociados a la pudrición seca de los tubérculos de ñame

Author(s):  
Diana Beatriz Sánchez-López ◽  
◽  
Lily Lorena Luna-Castellanos ◽  
Manuel Ramón Espinosa-Carvajal ◽  
Dairo Javier Pérez-Polo ◽  
...  

Dry rot of tubers is one of the most devastating diseases in yam production (Dioscorea rotundata Poir.) in the Caribbean region of Colombia. The disease attacks tubers, causing production losses during cultivation. In previous experiments, 11 fungal morphotypes were isolated and associated with this disease in yam crops in the Caribbean region of Colombia. The present investigation was carried out under greenhouse conditions to determine the infection capacity of these 11 possible causative agents, in 150-day-old plants of two yam genetic materials (0307-49SB y 0307-50CB). The results indicated that morphotypes DH2 (Lasiodiplodia theobromae), DH11 (Curvularia aeria), DH20 (Aspergillus niger), and DH17 (Fusarium equiseti), showed the highest infection capacity to yam tubers, regardless of the genetic material. Therefore, they were considered as the main causal agents of the disease in the Caribbean region of Colombia. The remaining seven (7) morphotypes, despite having been inoculated in the roots of the plants, showed minor effects on tubers and affected other organs of the plant, especially stems and aerial part of yam plant. This study allows concentrating the research on these four morphotypes to develop crop management strategies that might allow reducing the incidence of this disease in the Caribbean region of Colombia.

Plant Disease ◽  
2020 ◽  
Vol 104 (6) ◽  
pp. 1715-1724
Author(s):  
Qingjing Ye ◽  
Rongqing Wang ◽  
Meiying Ruan ◽  
Zhuping Yao ◽  
Yuan Cheng ◽  
...  

Fungal wilt and root rot diseases affecting tomato have become prevalent in China in recent years and have caused considerable damage. In 2016 to 2018, symptoms of putative wilt and root rot diseases were observed in several locations in tomato cultivars with resistance to Fusarium oxysporum f. sp. lycopersici races 1 and 2. The objective of this study was to identify the causative agents of wilt and root rot of tomato in China and provide a basis for disease prevention and resistance breeding programs. Based on DNA sequence analyses of the internal transcribed spacer (ITS) region, 91 isolates from the roots of tomato plants showing symptoms of wilt and root rot were identified, including F. oxysporum (64 isolates), Fusarium solani (11 isolates), Fusarium proliferatum (2 isolates), Fusarium graminearum (2 isolates), Fusarium equiseti (1 isolate), Pythium aphanidermatum (6 isolates), Ascomycota sp. (2 isolates), and Plectosphaerella cucumerina (3 isolates). F. oxysporum accounted for 70.33% of the isolates obtained. In this case, using PCR-based methods for differentiation of F. oxysporum, we identified several formae speciales and races of F. oxysporum: 7 isolates were identified as F. oxysporum f. sp. lycopersici race 1, 2 isolates as F. oxysporum f. sp. lycopersici race 2, 35 isolates as F. oxysporum f. sp. lycopersici race 3, and 13 isolates as F. oxysporum f. sp. radicis-lycopersici. Pathogenicity tests revealed 55 isolates of tomato wilt and root rot pathogens to be virulent. This study demonstrated that F. oxysporum f. sp. lycopersici race 3 was the most widespread and highly virulent race among these tomato pathogens in China, followed by F. oxysporum f. sp. radicis-lycopersici. Therefore, the development of resistant varieties of tomato against F. oxysporum f. sp. lycopersici race 3 and F. oxysporum f. sp. radicis-lycopersici would aid efforts to develop effective disease management strategies.


NeoBiota ◽  
2021 ◽  
Vol 64 ◽  
pp. 177-197
Author(s):  
Julissa Rojas-Sandoval ◽  
James D. Ackerman

Understanding the historical factors associated with the invasion success of alien species in a region may help us to identify sources, vectors, and pathways that are more likely to originate new invaders. Here, we gather data for traits related to the history of introduction (e.g., continent of origin, reason for introduction, and date of introduction) of 616 alien plant species listed as invasive on 18 island groups across the Caribbean region. We used these data to evaluate how human activity has influenced plant invasions on Caribbean islands over time and whether invasion success could be driven by traits of the introduction process. We found that significantly more invasive plants (54%) were intentionally introduced for ornamental reasons than for any other purpose. Most invaders in the Caribbean are native to Asia, South America, and Africa and the cumulative number of invasive species in this region has been steadily increasing during the last 200 years, but since 1850, this trend has been led by species introduced as ornamentals. We also found a significant association between continent of origin and reason of introduction, with more invaders than expected being ornamentals from Asia and America, and forage species from Africa. Our results show that introduced ornamentals are successfully invading all major habitats across the Caribbean, exacerbating conservation issues and threatening native biodiversity. Armed with knowledge of origins and reasons for introductions, effective biosecurity actions as well as control and management strategies can be better targeted to address the problem of invasive species in the region.


2019 ◽  
Vol 13 (04) ◽  
pp. 278-283 ◽  
Author(s):  
Jose Mateus ◽  
Natalia Gómez ◽  
María Teresa Herrera-Sepúlveda ◽  
Marylin Hidalgo ◽  
Jairo Pérez-Torres ◽  
...  

Introduction: Bats have become an epidemiologically significant source of pathogenic microorganisms, such as leptospires, the causative agents of leptospirosis. However, little information exists about bats and their potential role as a reservoir of pathogenic Leptospira spp. in Colombia. The aim of this study was to evaluate the presence of pathogenic Leptospira spp. in the kidneys of bats from the Caribbean region of Colombia deposited in the collection of mammals of the Museo Javeriano de Historia Natural (MPUJ-MAMM). Methodology: DNA was extracted from twenty-six kidney samples from a total of 13 species of bats captured in Colombia. First, 16S ribosomal RNA conventional PCR was performed to detect the presence of Leptospira spp. Then, in samples that tested positive, LipL32 PCR was performed to detect pathogenic Leptospira spp. by sequencing and phylogenetic analysis. Results: The presence of Leptospira spp. was observed in 7/26 (26.9%) bats from the following 6 species: Carollia perspicillata, Glossophaga soricina, Dermanura phaeotis, Uroderma bilobatum, Desmodus rotundus, and Lophostoma silvicolum, and pathogenic Leptospira spp. were detected in 4/26 samples (15.4%). Conclusions: This study suggests that bats present in the Caribbean region of Colombia could be potential reservoirs of pathogenic Leptospira spp.


Author(s):  
Lisa Williams

Scotland is gradually coming to terms with its involvement in slavery and colonialism as part of the British Empire. This article places the spotlight on the lives of African Caribbean people who were residents of Edinburgh during the eighteenth and nineteenth centuries. I discuss their varied experiences and contributions: from runaways and men fighting for their freedom in the Scottish courts to women working as servants in city households or marrying into Edinburgh high society. The nineteenth century saw activism among political radicals from abolitionists to anticolonialists; some of these figures studied and taught at Edinburgh University. Their stories reflect the Scottish capital’s many direct connections with the Caribbean region.


Author(s):  
Samuel Andrés Gil Ruiz ◽  
Julio Eduardo Cañón Barriga ◽  
J. Alejandro Martínez

Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1063
Author(s):  
Laura Gálvez ◽  
Daniel Palmero

In recent years, different postharvest alterations have been detected in garlic. In many cases, the symptoms are not well defined, or the etiology is unknown, which further complicates the selection of bulbs during postharvest handling. To characterize the different symptoms of bulb rot caused by fungi, garlic bulb samples were collected from six Spanish provinces in two consecutive years. Eight different fungal species were identified. The most prevalent postharvest disease was Fusarium dry rot (56.1%), which was associated with six Fusarium species. Fusarium proliferatum was detected in more than 85% of symptomatic cloves, followed by F. oxysporum and F. solani. Pathogenicity tests did not show a significant correlation between virulence and mycotoxin production (fumonisins, beauvericin, and moniliformin) or the mycelial growth rate. Penicillium allii was detected in 12.2% of the samples; it was greatly influenced by the harvest season and garlic cultivar, and three different morphotypes were identified. Stemphylium vesicarium and Embellisia allii were pathogenic to wounded cloves. Some of the isolated fungal species produce highly toxic mycotoxins, which may have a negative impact on human health. This work is the first to determine the quantitative importance, pathogenicity, and virulence of the causative agents of postharvest garlic rot in Spain.


Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 297
Author(s):  
Latiffah Zakaria

In tropical fruit crops, anthracnose is mainly caused by species belonging to the fungal genus, Colletotrichum. These phytopathogens can infect several parts of the fruit crops; however, infection during postharvest or ripening stages is responsible for major economic losses. Due to the formation of black to dark brown sunken lesions on the fruit surface, anthracnose reduces fruit quality and marketability. Among the most common tropical fruit crops susceptible to anthracnose are mango, papaya, banana, avocado, guava, and dragon fruit; these are economically relevant products in many developing countries. It is important to document that the newly recorded Colletotrichum spp. associated with fruit anthracnose can infect multiple hosts, but some species may be host-specific. By using multiple markers, many phylogenetic species of Colletotrichum have been reported as anthracnose-causing pathogens. Taking into account that disease management strategies strongly rely on adequate knowledge of the causative agents, updated information on Colletotrichum species and the hazard posed by the most recently identified species in tropical fruit plantations and harvested fruits becomes vital. Besides, the newly recorded species may be important for biosecurity and should be listed as quarantine pathogens, considering that tropical fruits are traded worldwide.


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