Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

El Ingeniero Agrónomo Alfredo Alvarado con sus estudios de maestría y doctorado, se posicionó como un excelente y reconocido taxónomo de suelos. Además, ha sido un gran docente, investigador y proveedor de conocimiento desde los años 70s. A lo largo de todos estos años, ha plasmado conocimiento amplio en forma simplificada y práctica en múltiples artículos científicos y libros. La experiencia de campo, su interacción con otras culturas como por ejemplo en Suramérica por varios años, para ayudarles a mejorar sus opciones siempre de la mano del conocimiento, lo hacen un profesional ejemplar. El deseo continuo de dar a conocer a través de la lectura y también mediante su escritura, permite que la experiencia sumada con saber haya quedado plasmada y disponible para las generaciones actuales y venideras.

Introduction. For the proper establishment of cocoa plantations, suitable technologies must be guaranteed to obtain quality seedlings (young plants sown and developed in bags) in the nurseries. Objective. To define quality indicators for cocoa seedlings produced via micro-grafting, depending on organic sources and arbuscular mycorrhizal fungi in a Brown Sialitic soil. Materials and methods. Between 2018 and 2019 in the nursery of the Empresa Agroforestal y Coco de Baracoa, the inoculation of the Glomus cubense and Rhizoglomus irregulare strains in substrates formed by earthworm humus and composted cocoa husk (3:1,5:1 v/v) was evaluated. A completely randomized design was used, with 50 postures per treatment, of which 25 were evaluated. At four months, the following were evaluated: plant height, stem diameter, aerial, root and total dry mass, foliar nutrient concentration (N, P, K), leaf area, slenderness index, Dickson Quality Index (DQI), and the percentage of mycorrhizal colonization. A simple rank analysis of variance was performed and Duncan’s comparison test (95 %) was applied. Results. The inoculation of G. cubense and R. irregulare, regardless of the source, significantly increased total dry mass (39 %), the leaf area (20 %) and the DQI (48 %) with respect to the controls. The DQI was significantly related (p<0.05) to total dry mass and leaf area (R2= 0.97). The inoculation with R. irregulare and G. cubense increased the leaf N, P, and k concentrations. Conclusions. The variables total dry mass, leaf area, slenderness index, and DQI showed an integrative character of plant growth and can be used as quality indicators for cocoa micro-grafts, based on soil : organic fertilizer relationships and inoculation with G. cubense and R. irregulare.

Introduction. The Amazon region has a great plant diversity, but studies on their propagation and growth have been carried out in few species. Objective. To evaluate the in situ and ex situ germination of Sterculia colombiana and its growth characteristics after planting in ground covers of primary forest and intervened areas. Materials and methods. The study was carried out in Napo, Ecuador, in the period 2019-2020. The germination of S. colombiana was characterized in the variables: days and percentage to emergence, plant height, stem diameter and number of leaves, under greenhouse conditions and planted at the collection site. The plants obtained in the germination test were transplanted to a ground cover of primary forest (in situ) and an intervened area with replacement vegetation (ex situ). Linear, quadratic, cubic, exponential, and logarithmic growth models for stem height and diameter were evaluated. The air and soil temperature and the physical-chemical characteristics of the soil were recorded. An analysis of variance was performed to determine differences in growth and survival between the plantation sites and between the plants obtained in the in situ and ex situ tests. Results. The seedlings obtained from greenhouses reported fewer days to emergence and higher values in the rest of the variables evaluated than those grown in situ. The plants developed in the different evaluated covers, without significant differences in growth at the end of the study, only a significant correlation at 5 % between stem diameter and air temperature was reported. Conclusions. Sterculia colombiana germinated in a greenhouse and developed in the transplant sites, without this influencing its growth. Temperature was the only factor that reported significant correlations with growth at the end of the evaluation period.

Introduction. The asian psyllid (Diaphorina citri Kuwayama) is the main vector of the bacterium Candidatus Liberibacter asiaticus that causes Huanglongbing (HLB) disease in citrus in Panama. Objective. To determine the geographic distribution and host plants of the asian psyllid within the citrus growing areas in Panama. Materials and methods. The study was carried out from June to October 2021 through systematic sampling within 46 localities associated with commercial citrus and home gardens in seven provinces of Panama. In each plant, two new shoots of 10 cm long were bagged with a magic-seal plastic bag to capture the specimens and introduce them into 2 mm plastic vials with 95 % alcohol for later identification. The study variable included the count of the total number of specimens, and the data was analyzed as a percentage. Results. Of the total of 73 collected samples, the presence of the Asian psyllid was confirmed in 21.92 % (16 samples). Its presence was positive in the provinces of Chiriquí, Coclé, Herrera, Panama, and West Panama, at altitudes of 17 to 1080 m.a.s.l. There was no presence of the psyllid in the provinces of Los Santos and Veraguas. Of the 16 samples that were positive, 50 % belonged to the myrtle plant, followed by orange (18.75 %), and creole lemon (12.50 %). Conclusion. The distribution of the asian psyllid vector of HLB in commercial citrus and home gardens in the main citrus growing areas in Panama was presented at different heights above sea level, mainly associated with the presence of the host plants such as myrtle, orange, and creole lemon.

Introduction. The commercial introduction of Coffea canephora in Cuba occurred in 1930. Research on nitrogen fertilizer requirements has been conducted, but has not included foliar analysis as a criterion for the diagnosis of nutritional status. Objective. To establish the critical intervals of foliar nitrogen content and the most appropriate sampling moment to propose corrections to nitrogen fertilization in coffee. Materials and methods. The investigation was carried out between 2008 and 2011. The response of the coffee plants to nitrogen doses (0, 50, 100, 150, 200 kg ha-1) was studied in a randomized block experimental design with four replicates in soils of the Cambisoles order. Leaf sampling was carried out at the stages of flowering, fruiting, grain growth, and beginning of maturation. The relationships between relative yield and fertilizer doses were determined, as well as between the foliar N concentrations and relative yield. The critical range of N contents (%) that allowed reaching 90 % to 100 % of the relative yields was estimated. Results. Critical nitrogen intervals (ICN) for yields between 90 % and 100 % were similar among years and locations for fruiting, although they varied among phenological stages. The highest foliar concentrations and the widest range of these (2,79–2,97 % N) were found at the beginning of fructification, which was considered the most appropriate time to correct the fertilization system employed. There was a relationship between the relative annual crop yields and the N foliar concentrations for the robusta coffee plants. Conclusions. The critical nitrogen intervals of foliar N in coffee plants was established in the fruiting stage with a concentration of 2.79 %. Sampling at the beginning of fruiting was the most appropriate to assess the correction of nitrogen fertilization.

Introduction. The modern sow has the genetic capacity to produce a greater number of piglets per litter and a higher milk production, which means that the animal has higher nutrient requirements. Objective. To evaluate the performance of sows and their progeny to the supplementation of a commercial product based on artichoke dry extract (Cynara scolymus) and betaine hydrochloride during the lactation period. Materials and methods. The study was carried out during the first semester of 2020, in the province of Limón, Costa Rica. A total of 42 lactating sows were used and distributed in three treatments: control diet (T1), control diet + 0.25 kg t-1 of commercial product (T2), and control diet + 0.50 kg t-1 of commercial product (T3); the diets were isoproteic and isocaloric. Results. The inclusion of the additive showed a tendency to improve (p=0.09) the parameters evaluated in the sow. Body condition score loss was lower (p=0.03) with the T2, while supplementation with 0.50 kg t-1 presented intermediate results. There were no significant differences (p>0.05) between treatments for the parameters evaluated in the litters (weaning weight, weight gain, and number of weaned piglets by sow). Conclusion. The use of the additive showed a tendency to improve feed intake in the sow during the lactation period, reducing body weight loss and corporal condition during this period. The inclusion of the additive did not improve the performance in the piglets. piglets/sow). Conclusion. The use of the additive tended to improve important parameters in the sow during the lactation period, however, more research is needed on the animal's response to the additive during lactation and in the following cycle to obtain conclusive results.

Introduction. Different fishing activities generate a waste volume related to the processing species (viscera, heads and bones), the discards of the companion fauna, species of low commercial value and the losses related to handling problems. Fish meal production is the most common process for recovery nutrients from these fish processing byproducts. However, those places with reduced infrastructure or where the volume of wastes produced do not justified the economic equation for conversion into fish meal or oil, the biological silage could be the technology of choice to promote a sustainable waste management. Objective. To compilate, organize and summarize literature related to biological fermentation of fish waste and its applications. Development. A bibliographic review was carried out (January 1994 - December 2020) referring to the comprehensive use of fishing residues mainly focused on the use of lactic acid bacteria in fish waste fermentation. The information was organized in different sections: fish silage, lactic acid bacteria and carbohydrate sources for biological silage. Conclusions. The studies analyzed in this review highlight the possibility of using a wide variety of carbohydrate sources, biological starters and fish waste fermentation conditions. The satisfactory results show the potential use of fish waste in different applications. This work could contribute to the fisheries that decide to adopt this kind technology in order to provide an innovative and viable recycling bioeconomy.

Introduction. Charcoal rot caused by Macrophomina phaseolina is a pathogen that survives in the soil through microsclerotia (Sclerotium bataticola stage). This pathogen affects different crops, among which soybeans (Glycine max L. Merrill) and corn (Zea mays L.) stand out due to their importance in Argentina. Objetive. To demonstrate that the cause of the deaths of soybean and corn plants in years of drought in the province of Misiones is charcoal rot. Materials and methods. Samples were collected from different locations in the province of Misiones, Argentina during February 2022. Through naked eye observation of diseased plants and with the help of stereoscopic and optical microscopy, the identity of the pathogen present was determined. Results. The presence of microsclerotia compatible with S. bataticola as the causal agent of charcoal rot was detected in corn and soybean samples in all samples from the province of Misiones. Conclusion. Charcoal rot caused by M. phaseolina is present in soybean and corn crops in the province of Misiones, Argentina.

Introduction. Rabbit meat has a high nutritional value, but its texture, toughness, and color impact consumers’ purchasing decisions, therefore making an improvement is desirable. Objective. To perform a physical, chemical, and microbiological characterization of rabbit (Oryctolagus cuniculus) meat and determine the effect of CaCl2 application on its quality. Materials and methods. In San José, Costa Rica, between January and September 2015, pieces of rabbit thigh marinated and unmarinated with CaCl2, cooked and uncooked, were analyzed both at initial time and after five days of storage. A complete proximal analysis and microbiological plating tests, pH measurement, drip loss determination, and color and texture measurement were performed. Results. The meat had a moisture content of 75.3 %, 2.8 % fat, 21.1 % protein, and 0.8 % ash. The proteins were distributed as 54.8 % sarcoplasmic, 35.1 % myofibrillar, and 10.1 % (SD=1.05) stroma. There were no significant differences in pH measurements. An initial load of psychrophilic organisms from abiotic sources was found. Regarding drip loss, unmarinated meat had a value of -1.0±0.7 %, and marinated meat had value of -0.1±0.6 %. The addition of CaCl2 produced a whiter meat; but after cooking, it had a more yellow color. No significant differences were found in tenderness when CaCl2 was added. Conclusions. The quality of the rabbit meat obtained was comparable to that reported in the literature. The addition of CaCl2 by marinating had no effect on the overall quality of rabbit meat under the conditions of the present study.

Introduction. Some species of thrips in the genus Frankliniella (Thysanoptera: Thripidae) are of quarantine importance in various crops in the Central American region. Meanwhile, several species of this genus have been reported as part of the visitor fauna and flowering plants, not only in plants with agricultural production. Objective. To record the species of  Frankliniella associated with avocado trees and their cultivars weeds in the central region of Costa Rica and to present a key for the identification of these thrips. Materials and methods. Sampling was carried out every two months in three different zones in the central region of Costa Rica during the years 2019 to 2021. Thrips from avocado and weeds were collected by tapping branches and were prepared for viewing under a conventional light microscope and identified by their morphology. Results. Twenty-two species of Frankliniella were identified, eighteen of which were associated with weeds growing in the same cultivars, while five species were directly associated with the foliage and flowers of the avocado tree. Conclusion. In the central region of Costa Rica, three species of the genus Frankliniella were found on the avocado tree during flowering stage: F. alonso, F. doris and F. nita, one species on the foliage: F. sandovalensis, and one species on both foliage and flowering: F. cephalica.