Browsing by Author "Torres, R."

Now showing 1 - 11 of 11
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    Effect of boscalid on postharvest decay of strawberry caused by Botrytis cinerea and Rhizopus stolonifer
    (2007) Sallato, B. V.; Torres, R.; Zoffoli, J. P.; Latorre, B. A.
    In Chile, gray mold (Botrytis cinerea) and leak (Rhizopus stolonifir) are the major storage diseases of strawberry (Fragaria x ananassa Duch.) that considerably reduce yields and quality, limiting its international commercialization. The effect of preharvest fungicide treatments and postharvest treatments against storage decays was studied. Based on the results obtained, the incidence of B. cinerea and R. stolonifer was significantly lower on 'Camarosa' strawberry fruits treated with boscalid or boscalid + pyraclostrobin between blossom and harvest. Similarly, incidence of B. cinerea and R. stolonifer significantly decreased at 5 degrees C and 20 degrees C after immersion treatments with boscalid (600 to 700 mg L-1) or cyprodinil + fludioxonil (371 + 250 mg U). These postharvest treatments provided 5 and 15 days protection against these molds when strawberry fruits were stored at 20 degrees C and 5 degrees C, respectively. Fenhexamid (750 mg L-1) arrested B. cinerea, but it was ineffective against R. stolonifer. Variable results were obtained with iprodione (750 mg L-1). Fungicide treatments bad no adverse effect on total soluble content, titrable acidity and firmness. Only boscalid+pyraclostrobin affected the external color of the treated fruits. In conclusion, fungicide treatments using new reduced-risk fungicides can be useful to extend strawberry shelf life for over a 15 day period. However, further research is needed to establish a commercial recommendation.
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    Effect of boscalid on postharvest decay of strawberry caused by Botrytis cinerea and Rhizopus stolonifer
    (2007) Sallato, B.V.; Torres, R.; Zoffoli, Juan Pablo; Latorre G., Bernardo
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    First Report of Monilinia fructicola causing brown rot on stored Japanese plum fruit in Chile.
    (2014) Latorre G., Bernardo; Díaz Ulloa, Gonzalo Alberto; Valencia Díaz, Ana Luisa; Naranjo, P.; Ferrada, Enrique E.; Torres, R.; Zoffoli, Juan Pablo
    In autumn 2013, fruit of Japanese plum (Prunus salicina) cvs. Angelino and Black Kat developed an unusual brown and soft rot after 2 months in cold storage (0°C) on nearly 1% of the fruit. Fruit showed small, circular, light brown spots that eventually destroyed the entire fruit. Small sporodochia appeared on the fruit surface. Fruit was harvested from orchards located near San Francisco de Mostazal (33°59′ S, 70°41′ W), Chile. Small pieces of diseased tissue were selected from margins of lesions of surface disinfected (96% ethanol) fruit (n = 7) and placed on acidified potato dextrose agar (PDA) plates for 5 days at 20°C. Light brown colonies with even margins and concentric rings of spores were obtained. The conidia of five isolates were one-celled, hyaline, lemon-shaped, (min. 10.7) 14.9 ± 1.5 (max. 18.6) × (min. 8.1) 9.4 ± 0.8 (max. 10.8) μm (n = 30), and borne in branched monilioid chains. This fungus was identified as Monilinia fructicola (G. Winter) Honey (1). Identification was confirmed by amplifying and sequencing the ribosomal ITS1-5.8S-ITS2 region using ITS1 and ITS4 primers (3). BLAST analysis of Chilean plum isolates (GenBank Accession Nos. KF148610 and KF148611) were 99 to 100% identical to isolates of M. fructicola originating from the United States (DQ314727 and HQ846966, respectively) and 100% identical to the first Chilean isolate (JN001480) found in nectarines originating from California at the supermarkets in Santiago in June 2009. Koch's postulates were fulfilled by reproducing brown rot symptoms on mature wounded Japanese plums cv. Angelino (n = 8) inoculated with 10 μl of a conidial suspension (105 conidia/ml) or with a mycelium plug (5-mm diameter). After 2 days in humid chambers (>80% relative humidity) at 25°C, all inoculated fruit developed brown rot symptoms with necrotic lesion means of 15.8 and 21.5 mm in diameter in fruit inoculated with conidia and mycelium, respectively. Non-inoculated control fruit remained healthy. Re-isolations were performed on PDA and the presence of M. fructicola was morphologically confirmed in 100% of the symptomatic fruits. To our knowledge, this is the first report demonstrating the presence of M. fructicola causing brown rot in stored Japanese plums in Chile after its first interception in 2009 in Chile, suggesting that this pathogen has been established in the field. Currently, M. fructicola is a quarantine organism under official control, restricted to Prunus orchards between Santiago and Nancagua in central Chile (2).
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    Identification of Phytophthora cryptogea as the Cause of Rapid Decline of Petunia (Petunia x hybrida) in Chile
    (AMER PHYTOPATHOLOGICAL SOC, 2008) Ampuero, J.; Latorre, B. A.; Torres, R.; Chavez, E. R.
    Phytophthora cryptogea was consistently isolated from diseased tissue taken from the crown and necrotic roots of grandiflora type petunia (Petunia x hybrida) that were collected in gardens in five Public parks in Santiago. Chile in 2004 and 2005. Symptoms included leaf wilting and foliar chlorosis. followed by partial necrosis. and extensive dark-brown to reddish cankers in the crown. Disease incidence was over 50% and infected plants died within 7 to 10 days after transplanting. This pathogen was identified oil the basis of colony morphology. morphological characterization of the sexual and asexual reproductive structures, and temperature range. The identification of Phytophthora cryptogea was further corroborated by the internal transcribed spacer sequence analysis (GenBank accession number EF093534). Isolates of P cryptogea were pathogenic oil 10-week-old white grandiflora petunia plants that were inoculated on the roots or on the crown using mycelium fragments, or via soil inoculation using zoospores. A rapid decline was observed after soil inoculation,, with zoospores. Root fresh weight decreased significantly and the root rot index and severity of foliage symptoms increased significantly (P <= 0.051), relative to noninoculated plains after 14 days Of incubation. Two isolates (Ph-1 and Ph-2) were pathogenic oil bell pepper and one isolate (Ph-1) was pathogenic oil tomato after root inoculation. Two isolates (Ph-2 and Ph-3) were pathogenic oil the fruit of avocado, bell pepper. cherry tomato. Cucumber. kiwifruit, lemon. pear. pepino, and potato tubers, demonstrating the pathogen's ability to cause postharvest infection of fruit of a wide range of host plants. The efficacy of mefenoxam at 0.1 mg/ml mixed with either chlorothalonil at 1.0 mg/ml or mancozeb at 1.6 mg/ml was demonstrated in this study. whereas chlorothalonil and mancozeb alone did not control disease development. No significant differences were obtained between foliage and soil drench applications,. This study demonstrated that P. cryptogea is the cause of the rapid decline found on petunia in Santiago. Chile and, to our knowledge. this is the first report giving a detailed description of a disease caused by P. cryptogea on petunia.
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    Increase in Cladosporium spp. populations and rot of wine grapes associated with leaf removal
    (ELSEVIER SCI LTD, 2011) Latorre, B. A.; Briceno, E. X.; Torres, R.
    Leaf removal reduces the epiphytic populations of several filamentous fungi found on grapevine (Vitis vinifera) Consequently this practice is used to prevent foliar diseases of grapevines and rots of grapes In this study the effects of leaf removal on Cladosporium rot (Cladosporium cladosporioides and Cladosporium herbarum) which often affects Cabernet Sauvignon in Chile were characterized The effects of leaf removal on epiphytic populations of Cladosporium spp on grape berry surfaces and on Cladosporium rot development were investigated Three leaf removal treatments were compared (i) severe leaf removal where leaves from two to three nodes above opposite and from all nodes below clusters were removed (ii) mild leaf removal where leaves opposite each cluster were removed and (iii) no leaf removal Regardless of the leaf removal treatment low population levels of Cladosporium spp were detected early in the ontogenic development of grape berries which increased as the berries matured reaching maximum populations on overripe berries Based on our results severe leaf removal favors the growth of Cladosporium spp on grape berries and increases the prevalence of Cladosporium rot at harvest This increase in Cladosporium spp was correlated with an increase in lenticel damage in Cabernet Sauvignon and Sauvignon blanc vines subjected to severe leaf removal Considering that Cladosporium rot significantly reduces yield and wine quality, farmers should avoid continuous exposure of grape clusters to sunlight in order to prevent severe outbreaks of Cladosporium rot (C) 2010 Elsevier Ltd All rights reserved
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    NUTRITION OF WOMEN IN CHILE
    (2017) Olagnero, G.; Mardones, F.; Passi Solar, Alvaro Rodrigo; Rosso R., Pedro Pablo; Torres, R.; Rozowski Narkunska, Samuel Jaime; Wood, J. C.; Fernandez, X.
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    The risk assessment index in grape powdery mildew control decisions and the effect of temperature and humidity on conidial germination of Erysiphe necator
    (2007) Bendek, C. E.; Campbell, P. A.; Torres, R.; Donoso, A.; Latorre, B. A.
    Powdery mildew (Erysiphe necator) is a major disease of grapevines (Vitis vinifera) in Chile. Severe outbreaks have occurred recently despite the use of strict fungicide programs to control it. The objectives of this study were to evaluate the infection risk assessment index (RAI), to predict conditions for E. necator infection, and to study the effect of temperature (T), relative humidity (RH) and free moisture (FM) on conidial germination and disease development. Conidial germination was affected by T, RH, and FM. There were significant (p < 0.001) interactions between E. necator isolates and T and between isolates and RH. Conidial germination was optimal at 25 degrees C. There was no germination at 5 degrees C and 35 degrees C. At 20 degrees C, conidia germinated at a low RH (33-35%). Germination increased at a RH between 47 and 90% but decreased at higher RHs. Powdery mildew development on Carmenere,Chardonnay,and Merlot vines increased linearly from 6 degrees C to 23 degrees C. These grape cultivars were all equally susceptible to E. necator. Incubation periods varied. It was 13 to 14 d at 20 degrees C or 23 degrees C, 19 to 24 d at 10 degrees C, and more than 23 d at 6 degrees C. Grape powdery mildew was markedly decreased when inoculated leaves were wet at 1 or 72 h post inoculation. In conclusion, RAI, determined on the basis of air T, was useful to decide on fungicide applications between grape bud burst and veraison in Chile.
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    The risk assessment index in grape powdery mildew control decisions and the effect of temperature and humidity on conidial germination of Erysiphe mecator
    (2007) Bendek Jara, Carlos Andrés; Campbell, Paul; Torres, R.; Donoso, A.; Latorre G., Bernardo
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    Weighted neurofeedback facilitates greater self-regulation of functional connectivity between the primary motor area and cerebellum
    (2021) Vargas, P.; Sitaram, R.; Sepúlveda, P.; Montalba, C.; Rana, M.; Torres, R.; Tejos Nunez, Cristian Andres; Ruiz, S.