Pablo Enrique Grijalba

• Doctor of Natural Sciences
• University of Buenos Aires

Soybean ( Glycine max ) is one of the most economically important crops in Uruguay and is affected by soybean stem canker (SSC) disease. The main pathogens involved are Diaporthe aspalathi , D . caulivora , D . longicolla and D . miriciae , causing similar symptoms, including brown‐to‐reddish necrotic lesions on stems and wrinkled, cracked seed coa...

Damping off of soybean, caused by Pythium spp., is favored by cool temperatures and wet soil conditions. The goal of this research was to determine the effect of three temperatures on growth and pathogen aggressiveness of three different species of Pythium (s.l.) associated with soybean in the Buenos Aires province. A total of 12 isolates of the mo...

Mesa Redonda (Microbiomas habitantes de suelo) 6to Congreso Argentino de Fitopatología. Septiembre 2024

Plant disease resistance genes are widely used in agriculture to reduce disease outbreaks and epidemics and ensure global food security. In soybean, Rps (Resistance to Phytophthora sojae) genes are used to manage Phytophthora sojae, a major oomycete pathogen that causes Phytophthora stem and root rot (PRR) worldwide. This study aims to identify tem...

The placement of Corynespora olivacea within the large genus Corynespora (Pleosporales) is controversial, because the species is distantly related to other congeners, including the type species C. cassiicola. Corynespora cassiicola is a polyphagous, cosmopolitan plant pathogen. Successful colonization of plant tissues requires the pathogen's effect...

Soybean damping off and root and stem rot are mainly caused by soil oomycetes and they can cause severe seedling stand reductions. Between 2013 and 2016, soybean production areas were surveyed in different localities of the north (NBA) and southeast (SEBA) of Buenos Aires Province. Plant, soil and post harvested grain samples were obtained, brought...

BACKGROUND The Diaporthe/Phomopsis complex (D/P) is a group of soybean seed‐borne fungi. The use of chemical fungicides, either for seed treatment or during the crop cycle, is the most adopted practice for treating fungal diseases caused by this complex. Worldwide, there is a search for alternative seed treatments that are less harmful to the envir...

Pythium aphanidermatum has a cosmopolitan distribution in the warmer parts of the world. The aim of this study was to identify the causal agent of damping off in soybean seedlings on late planting dates under hot conditions, from different locations in Buenos Aires province. The isolates induced different levels of plant and seedling death and grow...

Phytophthora sojae causes root and stem rot of soybeans. In Argentina, this pathogen has shown dramatic shifts in pathotype variability since its first discovery during the 1970s. The aim of this study was to report the presence and distribution of different pathotypes of P. sojae isolates from 2013 to 2015 in the southeast of Buenos Aires Province...

Genetic variation in Phytophthora sojae was compared between northern (NPS) and southern (SPS) Pampeana sub‐regions, in the core soya bean region of Argentina. Ninety‐three isolates from plants and soil were evaluated in the present study. The pathotype for each isolate was determined using the hypocotyl technique on a set of eight differentials. F...

[This corrects the article DOI: 10.1016/j.heliyon.2019.e01495.].

Soybean (Glycine max (L.) Merrill) is a globally important crop, providing oil and protein. Diaporthe/Phomopsis complex includes seed-borne pathogens that affect this legume. Non-thermal plasma treatment is a fast, cost-effective and environmental-friendly technology. Soybean seeds were exposed to a quasi-stationary (50 Hz) dielectric barrier disch...

BACKGROUND Use of fungicide seed treatments for control of soybean soilborne diseases such as Pythium damping-off has increased worldwide. However, emergence of Pythium strains resistant to metalaxyl-M has prompted the need for alternative technologies to fungicides for damping-off control. The use of phosphites (Phis) has been proposed as a method...

RESUMEN En el cultivo de soja Pythium spp. produce la pudrición de semillas y raíces, y “damping off”. El objetivo del presente trabajo fue verificar la relación entre el gen Rps 1k de resistencia a Phytophthora sojae y P. ultimum y P. irregulare. Cuatro genotipos de soja, dos con el gen Rps 1k (SE+1y SE+2) y dos sin el gen (SE-1 y SE-2) se sembrar...

Kikuyu grass (Pennisetum clandestinum) is a perennial plant that belongs to the Poaceae family. In Argentina, it is used in warm areas as tropical pasture, forage and grass in gardens and sports fields. Species of Pythium have a cosmopolitan distribution and are important pathogens of a wide range of plant hosts. In the spring of 2009, a new diseas...

Pythium rot in soybean may appear from seed germination to the middle of the growing season. Effective control of four fungicides applied preventively in soybean was evaluated. These seeds were placed in plastic trays containing commercial substrate tyndallizated, inoculated with Pythium. Two trials were conducted A) Based on fungicides recommended...

Soybean purple seed stain (S-PSS) is a destructive, worldwide distributed fungal disease caused by several Cercospora species. This work aims to shed light on the nature of the genealogical and genetic relationships amongst S-PSS causal agents. Fungal isolates were obtained from Argentina and Brazil, which belong to the leading countries in soybean...

RESUMEN Pythiuma phanidermatum provoca la podredumbre basal de plantas adultas de tomate. Debido a los se-veros daños que ocasiona en este cultivo, en el presente trabajo se evaluó la eficacia de cuatro productos comerciales aplicados en forma preventiva en macetas con suelo tindalizado e inoculado con el pató-geno, en las que se colocó un plantín...

Phytophthora root rot is one of the most serious diseases of soybeans in Argentina. Surveys of commercial fields and trial plots of soybean were conducted throughout the northern Pampeana subregion (Argentina) between 1998 and 2004. A total of 193 isolates of Phytophthora sojae were collected and classified into races or virulence formulae. Among t...

Diseases of soybean caused by Cercospora spp. are endemic throughout the world's soybean production regions. Species diversity in the genus Cercospora has been underestimated due to overdependence on morphological characteristics, symptoms, and host associations. Currently, only two species (Cercospora kikuchii and C. sojina) are recognized to infe...

Diseases of soybean caused by Cercospora spp. are endemic throughout the world’ssoy- bean production regions. Species diversity in the genus Cercospora has been underesti- mated due to overdependence onmorphological characteristics, symptoms, and host associations. Currently, only two species (Cercospora kikuchii and C. sojina) are recognized to in...

In roots of adult tomato plants a wet and brown lesion, extending 2-4 cm above the soil was observed. Diseased plants withered and died. The objective of this paper was to isolate and to identify the causal organism of these symptoms. General and selective culture media were used. After 24 hours colonies with white cottony mycelium were developed....

Basal root rot of mature plants of tomato caused by Pythium aphanidermatum (Oomycota). In roots of adult tomato plants a wet and brown lesion, extending 2-4 cm above the soil was observed. Diseased plants withered and died. The objective of this paper was to isolate and to identify the causal organism of these symptoms. General and selective cultur...

Diaporthe phaseolorum var. caulivora is the major causal agent of stem canker in soybean (CTS) in Argentina. It has appeared mainly in the Southern Pampeana sub-region, but also in warm areas, and it has been observed with different levels of incidence, severity and virulence. The objective of this work was to study the growth rate in vitro and the...

Pathogens within the Diaporthe complex cause seed decay, stem blight and stem canker on soybean, representing a serious threat for this crop species. We herein utilize worldwide sequence data retrieved from Genbank in order to assess the species boundaries between the soybean stem canker causal agents, and define whether or not they should be regar...

Since 1995 severe losses were recorded on the production of Chamelaucium uncinatum in the vicinity of La Plata. In 2010, with the aim to confirm the identity of the causal agent of Geraldton waxplant basal rot, molecular studies were added to the morphological observations of the pathogen. P. nicotianae was identified as the causal agent of the dis...

Rhododendron is a genus belonging to the family Ericaceae and contains over 1000 species commonly known as rhododendrons and azaleas (Dimitri, 1978). Phytophthora multivora is a species that was described in Western Australia in 2008 but before that it was misidentified as P. citricola (Scott et al., 2009). During the early spring of 2011, leaf spo...

Stem canker caused by Diaporthe phaseolorum var. caulivora is an important disease of soybean in Argentina. The objective of this study was to determine its survival ability in artificially infested straw under laboratory and field conditions. In laboratory, stem pieces of soybean, maize, sorghum, sunflower, potato and wheat were autoclaved, placed...

The genus Pythium (Pythiaceae (Peronosporomycetes - ex Oomycetes), Kingdom Straminipila) includes important pathogens, affecting a wide range of hosts of economic value, causing damping-off and decline of herbaceous and wooded plants due to rootlets rot. In order to acquire a more comprehensive vision of Pythium in Argentina, a review and an update...

El complejo Diaporthe/Phomopsis es un importante grupo de hongos patógenos de la soja. Dentro del mismo, Diaporthe phaseolorum var. caulivora es uno de los agentes causales del cancro del tallo. Veintitrés aislamientos de este hongo, provenientes de diferentes zonas geográficas de la provincia de Buenos Aires, fueron caracterizados morfológica y ge...

The genus Pythium (Pythiaceae (Peronosporomycetes-ex Oomycetes), KingdomStraminipila) includes important pathogens, affecting a wide range of hosts of economic value, causing damping-off and decline of herbaceous and wooded plants due to rootlets rot. In order to acquire a more comprehensive vision of Pythium in Argentina, a review and an updated r...

Dieffenbachia picta is a worldwide appreciated crop due to its ornamental value. In Argentina it is cultivated in warm provinces and in the outskirts of Buenos Aires city, where in spring 2007 a great amount of plants were lost in commercial greenhouses. Symptoms such as wilting and soaked lesions in the basal leaves began in four- to six-month-old...

This is the first report of Cylindrocarpon destructans causing leaf blight and root and rhizome rot of Rumohra adiantiformis. The fungus was consistently isolated from diseased tissue and identified as Cylindrocarpon destructans based on its morphological and cultural characteristics. The corresponding teleomorph (Nectria radicicola) was not detect...

Root and stem rot of rooted cuttings of young poinsettia plants were observed in a soil-less culture system in Buenos Aires Province, Argentina. Pythium aphanidermatum was identified as the causal agent of these symptoms. This is the first report of P. aphanidermatum affecting poinsettia in Argentina.

Diaporthe phaseolorum var. caulivora, the causal agent of soybean stem canker, was detected in Necochea (Buenos Aires province, Argentina), which is the southernmost record of the pathogen in South America.

A new disease of Spathiphyllum wallisii plants, characterized by leaf yellowing and wilting due to root and crown rot, was observed in nurseries of the Great Buenos Aires, Argentina. A fungus was consistently isolated from diseased tissue and identified as Cylindrocladium spathiphylli, on the base of its morphological and cultural characteristics....

Poinsettia (Euphorbia pulcherrima Will. ex. Klotzsch) is a worldwide potted or landscape ornamental plant that belongs to the Euphorbiaceae family. During 2003 and 2004, several symptoms were observed on poinsettia potted plants in nurseries and crops near Buenos Aires. Symptoms included irregular, brown, water-soaked spots on adult plants and leaf...

Root and basal stem rot, blighting, and wilting have been observed on Epipremnum aureum (Linden ex Andre) plants in many nurseries in and near Buenos Aires since 1997. Infected stem tissues show an intense dark brown discoloration and water soaking near the stem base that eventually leads to plant death. To determine the causal agent of the disease...