Guillermo Andrés Enciso-Maldonado

Grasshoppers of the order Orthoptera are part of traditional food systems in several regions and have nutritional, biocultural, and economic relevance. However, information on their benefits, risks, and sustainability is dispersed and supported by different levels of evidence. The objective of this review was to integrate scientific and documentary information on the nutritional composition, biocultural importance, socioeconomic use, traditional uses, sustainability, acceptance, and safety of grasshoppers, with emphasis on Sphenarium spp. in Mexico, and to describe research trends published from 2004 to 2024. A documentary review was complemented by a bibliometric analysis in Scopus. Original articles retrieved with the terms “Sphenarium purpurascens” and “chapulines” were considered, and the records were analyzed with VOSviewer. Fifty-five documents on S. purpurascens and 10 associated with the term chapulines were identified. Mexico accounted for the largest share of scientific production, whereas the main research lines addressed chemical composition, physicochemical properties, food formulation, nutrition, ecology, and health risks. The literature documents that grasshoppers provide protein, amino acids, lipids, and minerals, as well as their relevance in culinary practices, seasonal harvesting, and local income generation. Nevertheless, their composition depends on species, diet, developmental stage, and processing. Traditional medicinal uses do not constitute evidence of clinical efficacy, and consumption requires control of microbiological, chemical, and allergenic hazards. In conclusion, grasshoppers may complement dietary diversification and strengthen local economies, provided that their use is based on sustainable management, traceability, hygienic processing, labeling, and assessment of cultural acceptance.

Pyroligneous acid (PA), a by-product of biomass pyrolysis, has been proposed as an organic alternative to chemical fungicides. Two experimental phases were carried out in Itapúa, Paraguay, to evaluate the effect of PA on the severity of Septoria tritici blotch (STB) and on the productivity of wheat (Triticum aestivum L.). The pathogen was identified through morphological characterization of pycnidiospores and lesions, consistent with recent regional reports of Zymoseptoria tritici. In Phase I (2019 and 2023 growing seasons), a randomized complete block design (RCBD) with eight treatments was used: a chemical fungicide check (Pyraclostrobin + Epoxiconazole + Fluxapyroxad, 800 mL ha-1), an untreated check (0 mL ha-1), and six increasing doses of PA (1,000, 2,000, 3,000, 4,000, 5,000, and 6,000 mL ha-1). In Phase II (2024 growing season), a factorial RCBD (2×6) compared two wheat varieties (Itapúa 85 and Itapúa 90) and five fungicide treatments (zero, one, or two applications of chemical fungicide or PA at 3,325 mL ha-1, the dose corresponding to the quadratic optimum estimated from Phase I data and falling within the Phase I tested range of 1,000-6,000 mL ha-1. In Phase I, PA doses ≥ 3,000 mL ha-1 significantly reduced STB severity and increased spike number per square meter and grain yield compared with the untreated check, although the chemical fungicide produced the highest thousand-grain weight. In Phase II, one application of PA (8.68%) was statistically equivalent to two applications of chemical fungicide (7.98%) in reducing STB severity, while two applications of PA did not improve over the untreated check, possibly due to cumulative phytotoxicity associated with the low pH of the product. No significant treatment effects on yield were observed in Phase II. Collectively, the results suggest that PA at doses of 3,000-6,000 mL ha-1 can be a viable, lower-cost alternative for STB management in wheat grown under subtropical conditions of Paraguay.

El fósforo es un nutriente esencial para el crecimiento del maíz, cuya disponibilidad suele ser limitada. En este sentido, el uso de bioestimulantes puede favorecer su absorción y eficiencia, contribuyendo al desarrollo y rendimiento del cultivo. El objetivo del trabajo fue evaluar la eficiencia del cultivo de maíz en función a diferentes dosis de fósforo complementadas con bioestimulante en un suelo Alfisol. El experimento se estableció bajo un diseño de bloques completos al azar, con ocho tratamientos y tres repeticiones, en arreglo bifactorial: factor A: fertilización foliar con bioestimulante, y factor B: dosis de P?O? (0, 45, 90 y 135 kg ha-1). Cada unidad experimental tuvo una dimensión de 5 × 4 m (20 m2). La siembra se realizó en septiembre de 2024, utilizando el híbrido DKB 390. Se evaluó la altura de planta, altura de inserción de la mazorca, longitud y diámetro de mazorca, peso de mil granos y rendimiento (kg ha-1). Los datos fueron sometidos a análisis de varianza, comparación de medias mediante la prueba de Tukey al 1 y 5%, y análisis de regresión. Los resultados no mostraron diferencias significativas para el factor bioestimulante en la mayoría de las variables evaluadas. En cambio, las dosis de P?O? presentaron diferencias significativas en variables de crecimiento y rendimiento. La mayor altura de planta y de inserción de la mazorca se registraron con 135 kg ha-1 de P?O?; sin embargo, el mayor diámetro y longitud de mazorca, peso de mil granos y rendimiento se obtuvieron con 90 kg ha-1 de P?O?, alcanzando una producción de 2.336 kg ha-1. Se concluye que la dosis de 90 kg ha-1 de P?O? fue la más eficiente para las variables de longitud de mazorca, diámetro de mazorca, peso de mil granos y el rendimiento en las condiciones del estudio.

The increasing use of biological inputs in Paraguayan agriculture has created a need to evaluate their compatibility with chemical fungicides, given the limited available information. This study aimed to determine the compatibility between two commercial products, one based on Trichoderma viride and the other on Bacillus amyloliquefaciens, and five fungicide premixes used for soybean disease management, applied at different concentrations. The work was conducted under laboratory conditions in Paraguay and comprised three phases: (I) in vitro compatibility assessment between the biological agents and fungicides, (II) evaluation of the effect of compatible combinations on Cercospora sp. in fungicide-amended medium, and (III) determination of control efficacy on detached leaves. In Phase I, mancozeb maintained T. viride radial growth above 36 mm even at 1000 ppm, whereas Solatenol + prothioconazole and other triazole- and strobilurin-based mixtures completely inhibited T. viride growth from 50 ppm onwards. In Phase II, compatible combinations reduced the radial growth of Cercospora sp. on PDA from 4.1 cm in the untreated control to ≤0.1 cm with mancozeb + T. viride and to ≤0.2 cm with fungicide + B. amyloliquefaciens mixtures at 150-500 ppm, corresponding to inhibition levels ≥95%. In Phase III, preventive and curative applications of these combinations on detached leaves decreased disease severity from 40.5% in the inoculated control to ≤1.3% in treated leaves. These results indicate that mancozeb + T. viride and selected fungicide mixtures combined with B. amyloliquefaciens can be safely integrated into soybean disease management programs in Paraguay.

In Latin America, pasture-based systems form the backbone of cattle production, with tropical forage grasses providing the primary and most economical feed source for ruminants. These grasses are cultivated across millions of hectares because of their high biomass yield, adaptability to poor soils, and suitability for extensive grazing. However, shifting land-use patterns and climate change are pushing forage systems into more marginal environments, where water scarcity and declining soil fertility compromise productivity and nutritional quality. Despite their critical role in regional and global livestock supply chains, tropical forage grasses have historically received limited breeding attention, largely owing to biological constraints such as apomixis, polyploidy, and self-incompatibility. This review explores the current understanding of the molecular mechanisms regulating key morphophysiological traits in tropical forage species, focusing on plant responses to abiotic (e.g. drought, heat) and biotic (e.g. pests, pathogens) stress. We highlight progress in building genomic resources, with emphasis on quantitative trait locus (QTL) mapping, transcriptomics, and genome-wide association studies (GWAS), which are uncovering trait-linked markers that can inform selection strategies. Additionally, we examine how transgenic technologies and gene editing tools such as CRISPR-Cas can be employed to circumvent reproductive barriers and accelerate the development of improved cultivars. By integrating conventional breeding with cutting-edge molecular tools, we propose a roadmap for developing climate-resilient, nutritionally enhanced tropical forages to support the long-term sustainability of grass-based livestock systems.

La producción de maíz se ve comprometida por hongos micotoxigénicos como Fusarium, Aspergillus y Penicillium, que reducen el rendimiento y la calidad desde el campo hasta la comercialización, causando riesgos gastrointestinales y carcinogénicos en humanos y animales. El objetivo de este trabajo fue evaluar la eficacia de cuatro inhibidores fúngicos en granos de maíz almacenados bajo diferentes condiciones de humedad y tiempo. Se evaluaron extracto de Larrea tridentata (10 mL L⁻¹), azadiractina (20 mL L⁻¹), fosfuro de aluminio (3 mg L⁻¹) y mezcla de ácidos orgánicos (ascórbico 1%, cítrico 0,25%, láctico 0,25%) contra A. flavus, A. fumigatus y F. verticillioides en granos almacenados a 12, 15 y 18% de humedad durante 120 días. Se utilizó un diseño factorial (tres hongos × tres humedades × cinco tratamientos) en arreglo completamente al azar. Los inhibidores mostraron residualidad menor a diez días. En cámara húmeda, la incidencia fúngica aumentó de 8-19% a diez días de incubación hasta superar 96% a treinta días. Tras noventa días de almacenamiento, A. flavus presentó la menor incidencia (9,5%) en granos con 12% de humedad, mientras que A. fumigatus y F. verticillioides alcanzaron 42,0% y 15,0%, respectivamente. Las aflatoxinas se detectaron únicamente en granos con 18% de humedad, alcanzando concentraciones máximas de 6,5 mg kg⁻¹ (A. flavus) y 11,0 mg kg⁻¹ (A. fumigatus). Los resultados subrayan la necesidad de mantener la humedad por debajo del 12% y aplicar inhibidores fúngicos tempranos para prevenir la producción de micotoxinas durante el almacenamiento del maíz.

Maize (Zea mays L.) is a cornerstone of food security and livestock production in Paraguay. However, its productivity and grain safety are increasingly threatened by Fusarium species because of their pathogenic capacity and ability to produce mycotoxins. In this study, symptomatic maize leaves collected from commercial fields in Pirapó, Itapúa, during the 2022 growing season were processed to isolate and characterize fungal pathogens. Three isolates displaying typical Fusarium morphology were obtained and examined through macroscopic and microscopic traits. Molecular identification was conducted using translation elongation factor 1-α 1-α (TEF) sequences, followed by phylogenetic inference using maximum likelihood and Bayesian methods. The Paraguayan isolates (PYF-MZE22-01, -02, -03) clustered with the ex-type strain Fusarium awaxy CBS139380 in a strongly supported clade, confirming species identity. This finding constitutes the first record of F. awaxy associated with maize in Paraguay, thereby expanding its known geographical distribution. Considering that members of the Fusarium fujikuroi species complex are recognized producers of regulated mycotoxins, the detection of F. awaxy raises concerns regarding its pathogenic potential and possible implications for food safety. These results underscore the importance of integrating molecular diagnostics, toxigenic profiling, and surveillance programs to monitor emerging Fusarium taxa in South American agroecosystems.

Asian soybean rust (ASR), caused by the fungus Phakopsora pachyrhizi, significantly reduces crop yield and leads to increased costs associated with fungicide application. A comprehensive literature review was conducted covering the period from 2000 to 2023, focusing on articles related to Phakopsora pachyrhizi in the MERCOSUR region (including Argentina, Brazil, Paraguay, and Uruguay). This systematic review compiled findings from 474 scientific articles, examining publication trends, authorship, countries, citations, and research topics. Key topics included genetic mutations in the describedorganisms, control efficiency data to assess trends in fungicide efficiency, and areas under the disease progress curve. Since 2005, the number of publications has doubled, with Brazil leading the research. The review highlights the growing prevalence of mutations in P. pachyrhizi, which contribute to reduced fungicide efficacy and increased resistance.

This work analyses the genetic potential of Stevia rebaudiana beyond its sweetening properties, aiming to reassess its conservation and utilization in breeding programmes. This focus is justified by the growing global demand for natural sweeteners and the challenges posed by extreme weather events and diseases affecting crop yield and quality. The relationship between the species’ genetic diversity and its response to biotic and abiotic stresses is explored, as well as the limitations of current conservation and breeding strategies. Findings reveal underutilized genetic resources, limited integration of genomic tools in breeding efforts and a lack of robust in situ conservation initiatives. Genotypic variability has been observed in response to diseases such as Septoria leaf spot, while abiotic factors, including salinity and drought, can significantly influence steviol glycoside content. It is concluded that an integrated approach, combining dynamic conservation, photoperiod‐informed breeding strategies, improvements in seed viability, omics‐based tools and coherent public policies, is essential to ensure crop resilience and genetic sovereignty, especially in regions of origin such as Paraguay. The sustainable use of Stevia ’s genetic diversity could foster more sustainable, healthier and fairer production systems.