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The primary objective of this research study is to assess the performance of 25 genotypes of "criolla" or "chaucha" potato (Solanum tuberosum group phureja) under natural infestation conditions of the phytopathogen Rhizoctonia solani. A randomized complete block design with three replications is conducted in the Mapachico district, Pasto-Nariño (Colombia). The results show that during the first evaluation stage, the Criolla-Colombia genotype present the lowest phythopathogen incidence (5.74%). During tuberization, the Mambera and Ratona-Rosada genotypes show an 18.92% incidence each, and at harvest, the Ratona-Rosada shows a 10.27% incidence. The genotypes Ratona-Amarilla, Ratona-Rosada, and Criolla-Galeras achieve the highest commercial yield with 20.49, 21.25, and 23.39 t. ha-1 respectively. It is concluded that the S. tuberosum genotypes Criolla-NN, Mambera, Ratona-Amarilla, Ratona-Rosada, Criolla-Galeras, Criolla-Colombia, Tornilla-Negra, Punte, and Ratona are the best prospects for genetic improvement programs because of their low susceptibility to the phytopathogen R. solani. [ABSTRACT FROM AUTHOR]

Objective. To quantify the laccase activity of Bipolaris sp. in liquid fermentation with different culture media. Materials and methods. A strain of Bipolaris sp was reactivated in Potato Dextrose Agar (PDA). Four liquid culture media were prepared: 1) Sivakumar, 2) Czapek-Dox (modified), 3) wheat bran buffer citrate (WBBC), and 4) coconut palm leaf extract (CPLE). In 250 mL Erlenmeyer flasks, 120 mL of each type of culture medium were deposited and sterilized at 121 °C (15 lbs pressure) for 15 minutes. Three mycelium-agar disc of Bipolaris sp. were inoculated in each flask, incubated for seven days at 28 °C with constant agitation at 120 rpm and 28 °C. At 72, 120, and 168 hours, the laccase and total protein quantity were quantified in spectrophotometrically by spectrophotometer. Results. The WBBC medium showed a higher production (P<0.05) of laccases volumetric activity in the three samplings carried out with 395.5, 560.5, and 283.7 U/L, respectively. On the other hand, the Czapek-Dox showed no activity of specific activity in the laccase and total protein. The WBBC allowed a higher production (P<0.05) of total protein with 384.81 mg/L in relation to the STBC medium. Conclusions. The wheat bran buffer citrate culture medium was the best to produce laccase and total protein by Bipolaris sp. in liquid fermentation. In contrast, the Czapek-Dox culture medium (modified) was the least suitable to produce laccase and total protein. [ABSTRACT FROM AUTHOR]

Copyright of Ecosistemas y Recursos Agropecuarios is the property of Universidad Juarez Autonoma de Tabasco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of the research was to evaluate the in vitro antifungal activity of two extracts, governor (Larrea tridentata L.) and mustard (Sinapis alba L.) added with nanoparticles of silicon oxide (SiO) and zinc oxide (ZnO), on the mycelial growth and sporulation of Fusarium acuminatum. The poisoned medium method was used, inhibitory concentrations and the number of conidia were determined. Data were analyzed using a probit analysis, ANOVA and Tukey test (p = 0.05). The results showed that mustard treatments with ZnO have a better inhibitory effect and in sporulation governor treatments with SiO. Extracts added with nanoparticles are effective in the in vitro control of F. acuminatum. [ABSTRACT FROM AUTHOR]

Context: A plant disease is the result of the interaction between a susceptible host, a virulent pathogen and favorable environmental conditions. Several anthropogenic and environmental factors have favored the emerging and re-emerging of diseases that have led to crop losses. Globally, in recent years there have been a series of first reports of pathogens that have appeared in certain geographical areas or attacking different hosts, including the development of variants, strains and new species of some pathogens. Knowledge Gap: However, in addition to these reviews that describe the factors that direct or explain the emerging of particular pathogens, there is no review that highlights the emerging of plant diseases in Latin America. Neither is there an update of the pathogen groups of the genera Candidatus Liberibacter and Phytoplasma that would allow a comprehensive knowledge of them. Study purpose: To comprehensively review the occurrence of emerging and re-emerging plant diseases in Latin America in the last five years, to highlight some pathogens of considerable importance in the region and to update the information on the groups of Ca. Liberibacter and Ca. Phytoplasma. Methodology: A search was made in different bibliographic databases, limiting the information to the geographic region and the last ten years, highlighting the results of the last five years, without excluding basic articles for the different groups of pathogens. Additionally, a specific search was made for the genera Ca. Liberibacter and Ca. Phytoplasma. Results and conclusion: Latin America experiences emerging and re-emerging plant diseases evidenced in a large number of first reports for different countries; in addition to studies indicating geographic expansion, host range of pathogens, appearance of new races, strains and variants, and even species of viruses, viroids, bacteria, fungi and oomycetes. For the genera Ca. Liberibacter and Ca. Phytoplasma new hosts of the groups were found in relation to those initially reported. It is concluded that Latin America presents a large number of reports for emerging pathogens, but also some reemerging diseases continue to cause problems, and the information summarized in this review is key to make known the existence of these problems in the region. [ABSTRACT FROM AUTHOR]

Contextualization: Fusarium graminearum is a field microorganism that affects grasses and causes great losses, particularly to rice crops. To counter these phytosanitary problems, excessive amounts of pesticides are applied, causing damage to health and the environment. An alternative is to plant extracts with a high content of bioactive compounds. Knowledge gap: The pyrogallol tannins contained in Caesalpinia spinosa pods have biological properties, Fusarium graminearum's micellial growth inhibition is effective at low concentrations of UFC/ml. Purpose: Therefore, the objective in this research was to determinate in vitro the antifungal activity of tare phenolic compounds (Caesalpinia spinosa) against Fusarium graminearum. Methodology: Firstly, the phenolic compounds extracted by maceration and heating (60 °C) through water and ethanol-water mix, the phenolic compounds content in the extracts determined by Folin-Ciocalteu method. Secondly, a Fusarium strain obtained from a rice culture isolated and identified by taxonomic keys, after cell suspensions made with concentrations 107 and 106 UFC/ml. For in vitro evaluation, a disc with an inoculum of each suspension placed in a culture medium containing C. spinosa extract. Results and conclusions: Consequently, the aqueous extract by heating with a content of 5.88 g gallic acid/100 g dry sample inhibited 30 and 70% of mycelial growth of Fusarium graminearum with a concentration of 107 and 106 UFC/ml. Phenolic compounds of Caesalpinia spinosa have properties of interest for the control of Fusarium graminearum and can be tested in vivo, in the greenhouse. [ABSTRACT FROM AUTHOR]

Fungi as biological controllers are important in development of bioproducts for sustainable agriculture in the management of phytopathogens such as Sclerotinia sp., which causes white rot in lettuce, crops insomuch as infectious viability in soil lasts up until five years. Lettuce cultivation is essential in Colombia's agricultural economy, and Sclerotinia sp. causes losses until 50% of crops. The aim of this work was to evaluate in vitro the antagonistic capacity of three strains of Trichoderma sp. Tr1, Tr2 and Tr3 and, three strains of Aspergillus sp. As1, As2 and As3 against Sclerotinia sp Scl., individually and in consortia. Recovering, maintenance and evaluation of fungi was carried out by mediums as PDA, V8 Juice and Honey-Oat. The control strains -Tr1, Tr2, Tr3, As1, As2 and As3- were confronted among them and in consortia against the phytopathogen with dual technique. The consortia As1+As2+Tr2, As1+As2+Tr1, and As1+As2+Tr3 had a degree of inhibition on the phytopathogen, being more efficient the combination As1+As2+Tr1 -85,1%-; and individually the strains Tr2 and As1 with an efficiency of 95,6% and 95,1%, respectively. It was corroborated that the growth of Scl. using the consortia was not more than 14,9% in the best treatment. In none of the confrontations with the consortia was evidence of sclerotia formation, resistance structure for infection process and persistence in soils after to ten days of evaluation. [ABSTRACT FROM AUTHOR]

The antifungal effectiveness of aqueous extracts of coconut mesocarp (Cocos nucifera L.) (AEC) and commercial chitosan (CQ) applied individually and in combination was evaluated against Rhizopus stolonifer in terms of mycelial growth, sporulation, spore germination, as well the primary growth models at two storage temperatures (15-25 oC) was obtained. The use of AEC applied individually, significantly reduced the mycelial growth of R. stolonifer (> 45 %); on the other hand, CQ (1.5 %) showed up to 87 % of control, however, the combination of AEC (10 %) with CQ (1.5 %) was more effective in reducing mycelial growth (> 93 %). All treatments were effective in inhibiting spore production (> 94 %) compared to control (agar). CQ combined with AEC was more effective by inhibiting the germ tube elongation (> 98 %) compared to the individual treatments (< 48 %). The modified Gompertz model showed an adequate fit for both temperature ranges (> 98-99 %), observing significant differences (p ≤ 0.05) between the variables maximum speed (Vmax) and latency period (ƛ), however all treatments showed a fungistatic effect on the mycelial development of R. stolonifer. The combination of AEC and CQ can be an eco-friendly alternative against soft rot in soursop fruits. [ABSTRACT FROM AUTHOR]

Copyright of Revista Colombiana de Investigaciones Agroindustriales is the property of Revista Colombiana de Investigaciones Agroindustriales del Centro Agropecuario Sena Buga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Biológico Agropecuaria Tuxpan is the property of Revista Biologico Agropecuaria Tuxpan and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Mexicana de Ciencias Agrícolas is the property of Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Black Sigatoka is the most destructive disease of the leaves of bananas. The increased resistance of the pathogen and the contamination caused by chemical fungicides have guided the search for control alternatives. The objective of the work was to determine the effect of the combination of extracts of garlic (Allium sativum) and clove (Syzygium aromaticum) in the development of Mycosphaerella fijiensis. The phytopathogen was grown in potato-dextrose-agar (PDA) media added with different concentrations of extracts. A factorial design of two factors at four levels was established. At higher concentration of garlic extract, less capacity to inhibit M. fijiensis colony. In contrast, the clove extract showed greater inhibition capacity at the higher concentration. The greatest inhibition of the growth, 39.6%, was with the mixture of 150 mg of garlic extract·ml-1 and 36 mg of clove extract·ml-1. [ABSTRACT FROM AUTHOR]

Copyright of Agro Productividad is the property of Colegio de Postgraduados and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Archivos Latinoamericanos de Nutrición is the property of Sociedad Latinoamericana de Nutricion and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of the work was to determine the antagonistic activity of 13 strains of Trichoderma asperellum Samuels, Lieckfeldt & Nirenberg against two isolates of Fusarium (Fusarium dlaminii Marasas, Nelson & Toussoun and Fusarium solani (Martius) Appel & Wollenweber emend Snyder & Hansen) of beans (Phaseolus vulgaris L.). Antibiosis, competition for space, and mycoparasitism were determined by the dual culture method. All strains of T. asperellum evaluated, with the exception of Ta. 78, inhibited the growth of phytopathogens after 48 h. The antagonist strains, except Ta. 3 that was placed in class 2, were grouped into class 1 of Bell's scale. The Trichoderma strains showed the highest percentages of growth inhibition of the phytopathogens with the highest number of hyphal interaction types in Ta.1 with F. dlaminii (4447 %) and Ta. 79 with F. solani (41- 48.72 %). According to the results of their mode of action, the strains Ta. 1 and Ta. 79 were selected as promising for the biological control of these phytopathogens. [ABSTRACT FROM AUTHOR]

Copyright of Revista Colombiana de Ciencias Hortícolas is the property of Revista Colombiana de Ciencias Horticolas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rhizoctonia solani is an important pathogen of potato, which affects the emergence and development of the plant and causes deformation of the tuber. Currently strategies to control this pathogen are based on synthetic fungicides and this has originated cases of resistance. Therefore, 31 strains of Trichoderma against R. solani (TJ53, ACH42 and HSO56) were evaluated in vitro. For this, trials in dual cultures, volatile and non-volatile compounds were established, using Petri dishes with medium Potato Dextrose Agar (PDA). T. asperellum T18 and T16 showed antagonistic effect in three tests on all R. solani strains. Results suggest that the next stage would include greenhouse and field evaluation of T. asperelllum (T18 y T16) and T. rossicum (T1) against R. solani strains. [ABSTRACT FROM AUTHOR]

The in vitro control of strains of Burkholderia cepacia, Bacillus subtilis and Serratia plymuthica against Macrophomina phaseolina (Tassi) Goid was evaluated by the dual culture method. The radius of the fungal colony was measured, and the inhibition percentage of the radial growth determined.. The B. cepacia strain showed the strongest inhibitory effect on the M. phaseolina isolate with a 43.5% of inhibition, also causing changes in the mycelium appearance on the inhibition zone, which were observed with the optical microscope. S. plymuthica and B. subtilis showed values of mycelia growth inhibition lower than 10% indicating that these strains were not useful as biological controls of this pathogen. Greenhouse and field studies on the B. cepacia strain are required to determine its potential use as a biological control agent of the pathogen. [ABSTRACT FROM AUTHOR]

Phytophthora cinnamomi Rands is considered the most limiting pathogen of avocado, affecting the root system of plants from the nursery stage until their establishment in the field. Chemical control, as a management alternative, generates risks for public health and environmental contamination due to the indiscriminate use of highly toxic products, therefore, the use of biocontrol is an alternative to sanitary problems in nurseries and established crops. The objective of this work was to determine the antagonistic capacity of Trichoderma atroviride, T. longibrachiatum, T. harzianum and T. koningiopsis belonging to the collection of isolates of the microorganism bank of the Corporación Colombiana de Investigación Agropecuaria (Agrosavia) against five isolates of P. cinnamomi obtained from Hass avocado trees affected by root rot, which were selected for their high virulence. The radial growth inhibition percentage of P. cinnamomi and the mycoparasitism percentage of the Trichoderma spp. strains were evaluated by in vitro bioassays, carried out as dual antagonistic tests, under a completely randomized experimental design (CRD) with factorial arrangement. The results obtained showed that the four Trichoderma species evaluated induced mycelial inhibition percentages of P. cinnamomi higher than 39% and a mycoparasitism degree between 3 and 4. These strains are promising for evaluation tests under nursery and field conditions for the management of avocado root rot. [ABSTRACT FROM AUTHOR]