María Guzmán-Martínez

Objective: To evaluate the effect of three Heterorhabditis nematode isolates obtained from different agroecosystems on adults of Sphenophorus incurrens, a phytosanitary problem in sugarcane (Saccharum spp.) cultivation. Design/Methodology/Approach: Adult weevils were collected from the field using bait traps and transported to the laboratory. To assess LC₅₀, LT₅₀, and the efficacy of these native nematodes, bioassays were conducted using doses of 0, 10, 50, 100, 200, 500, 1000, and 5000 infective juveniles (IJs)/adult weevil in 12-well cell culture plates over a period of 10 days. Results: All three isolates exhibited pathogenicity against sugarcane weevils at all tested doses, except the control. The most virulent strain was Heterorhabditis bacteriophora (C-23), isolated from cattle-grazed soils, with an LC₅₀ of 2,626 IJs/weevil (P < 0.0001) and an LT₅₀ of 17.7 days (P < 0.0001). Limitations/Implications: This is the first known study evaluating EPNs against adult S. incurrens under laboratory conditions. Future studies should include field evaluations of these nematodes and their target pest. Findings/Conclusions: The observed variation in weevil mortality likely relates to the ecological niche, host interaction, and life history of each nematode isolate. These findings support the potential of entomopathogenic nematodes as a viable biological control option for managing S. incurrens in sugarcane cultivation.

Calcium (Ca) is essential for tomato (Solanum lycopersicum L.) fruit quality and for preventing physiological disorders such as blossom-end rot. However, high total soil Ca does not necessarily translate into plant-available Ca due to factors such as soil pH and limited mobility. This study evaluated soil Ca availability and the effect of a chicken manure-based soil amendment on the growth and yield of four tomato genotypes (Pony Express F1, Palomo F1, Toro F1, and Perseo F1) grown on a loam–clay–sand soil containing 4886 ppm Ca. In the first cycle, conducted in a shade house, two Ca application levels (0% and 25% of the crop’s requirement) were tested. The 0% treatment outperformed the 25% treatment regarding yield-related traits, indicating that native soil Ca met crop demand; application of 25% Ca reduced total fruit weight and fruit number by 19.7% and 5.9%, respectively, while the 0% treatment produced 40.8% more first-quality fruits. Perseo F1 (Perseo) produced the highest yield of first-quality fruits (20.61 t ha⁻¹), exceeding Pony Express F1 (Pony express), Palomo F1 (Palomo), and Toro F1 (Toro) by 10.8%, 6.6%, and 51.4%, respectively. In a second cycle under open-field conditions, incorporation of the chicken manure amendment significantly enhanced growth and yield: treated plants reached a 0.85 m height 58 days after transplanting, and overall yield increased to 70.08 t ha⁻¹ compared with 50.30 t ha⁻¹ in the control (21.9% increase). These results indicate that, while native soil Ca can satisfy crop requirements under the studied conditions, soil amendment under field conditions substantially improves plant performance and commercial yield potential.

Sugarcane (Saccharum spp.) is a crop of significant industrial and nutritional value, essential for producing various products. Due to its importance, genetic improvement programs involve a rigorous selection process. In this study, growth curve models were used to analyze the maturity curves of 33 hybrids (currently in the adaptability testing phase) and 6 control varieties (MEX 69-290, ITV 92-1424, CP 72-2086, COLMEX 94-8, COLMEX 95-27, RB 85-5113) during both plant and ratoon periods at the Melchor Ocampo Sugar Mill fields in Jalisco, México. With the use of clustering techniques, the materials were classified into four maturity groups: early, early–intermediate, intermediate–late, and late. Hybrids with a larger intercept and smaller slope were classified as having early and early–intermediate maturity. Conversely, hybrids with a smaller intercept and larger slope were classified as having intermediate–late and late maturity. According to the Connectivity and Dunn indexes, the DBSCAN algorithm provides the best clustering structure for materials in the plant cycle, while for the ratoon cycle, the k-means algorithm offers the best clustering structure. This highlights the versatility of each algorithm in the context of hybrid and varietal maturity analysis. These results are crucial for optimizing the productivity and sustainability of the crop, with significant implications for the sugar industry.

Anthropic activities such as agriculture, livestock, and wastewater discharges affect water quality in the Tlapaneco River in the mountain region of the state of Guerrero, México, which is a tributary of the Balsas. The river flows from the mountain region and discharges into the Pacific Ocean; the water resource in the localities mentioned is used for agriculture, recreation, and domestic activities. The aim of this study was to evaluate water quality in the stretch of influence of two localities, Patlicha and Copanatoyac. The instrument used was the Biological Monitoring Working Party biotic index (BMWP) and physicochemical parameters. Nine sampling sites were selected according to the perception of the local community with respect to disturbance; the study area was divided into three parts: high, medium, and low. Twenty-seven collections of macroinvertebrates and water were analyzed, in dry and rainy seasons, through the presence–absence of these organisms and physicochemical analysis, to evaluate water quality. The results showed that the conditions of the riverbed associated with daily activities and domestic discharges are important factors in the composition of the families. Water quality was very poor to regular, according to the macroinvertebrate assemblages collected. The BMWP index was of acceptable quality when the orders (Family) Ephemeroptera (Leptohyphidae; Leptophlebiidae; Baetidae; Ephemerellidae), Diptera (Chironomidae; Simulidae), Trichoptera (Hydropsychidae), Hemiptera (Veliidae; Corixidae), Coleoptera (Hydrophylidae), and Odonata (Lestidae) were present; in sites with poor quality, the families Chironomidae, Leptophlebiidae, Veliidae, Corixidae, Hydropsychidae, Leptohyphidae, Hydrophilidae, Baetidae, and Simuliidae were found, while in very poor quality water, only family Corixidae was present.

Anthropic activities as agriculture and livestock and wastewater discharges affect water quality in the Tlapaneco river in the Montaña region of the state of Guerrero, México, which is a tributary of the great Balsas River that flows from the Montaña and discharges into the Pacific Ocean; the water resource in the localities mentioned is used for agricultural work, recreation, and domestic tasks. The objective of the work was to evaluate quality of the water in the stretch of influence of two localities, Patlicha and Copanatoyac. The instrument used was the BMWP biotic index and some physicochemical parameters. Nine sampling sites were selected according to the perception of the local community with respect to disturbance; the study area was divided into three: high, medium and low. Twenty-seven collections of macroinvertebrates and water were analyzed, in dry and rainy seasons, through the presence-absence of these organisms and physicochemical analysis to evaluate water quality. The results showed that the conditions of the riverbed associated with daily activities and domestic discharges are important factors in the composition of the families. Water quality was very poor to fair according to the macroinvertebrate assemblages collected. The BMWP index with fair quality was when the families Leptohyphidae, Chironomidae, Hydropsychidae, Leptophlebiidae, Baetidae, Simuliidae, Veliidae, Corixidae, Hydrophylidae, Lestidae and Ephemerellidae were present; in sites with poor quality, the families Chironomidae, Leptophlebiidae, Veliidae, Corixidae, Hydropsychidae, Leptohyphidae, Hydrophilidae, Baetidae and Simuliidae were found, while in very poor quality the family present was Corixidae.

Anastrepha ludens Loew (Diptera: Tephritidae) is a pest of fruits that is attracted by the volatile compounds that emanate from fruit. In citrus (Sapindales: Rutaceae), this pest primarily feeds on the pulp and develops inside orange ( Citrus x sinensis (L.) Osbeck) and grapefruit ( Citrus x paradisi Macfad.) fruits, which cause substantial economic losses. The degree of infestation by citrus variety is still unknown, and determining these levels would be ideal to optimize the strategies for phytosanitary control. The objective of this study was to quantify and compare the level of infestation of A . ludens larvae in bitter orange ( Citrus x aurantium L.), navel orange ( C. x sinensis ‘Naval orange’), early orange ( C. x sinensis ‘Marr’s Early), Valencia orange ( C. x sinensis ‘Valencia’) and red grapefruit ( C. x paradisi ‘Red blush’). The study was conducted from August 2018 to July 2019 in the municipalities of Gómez Farías, Güémez, Hidalgo, Llera de Canales and Victoria, Tamaulipas, Mexico. In these municipalities, larval instars of A . ludens were sampled by collecting eight to 15 fruits hanging from the tree or lying on the ground; fruits were collected with yellow or necrotizing circular spots and signs of premature maturation. The infestations of A . ludens larvae among the five varieties were quantified by a multivariate analysis of variance and discriminant function analysis. Our results showed that the number of second instar larvae per fruit was responsible for the variation (separation between varieties), and they prefer bitter orange compared to the other four varieties of citrus that were analyzed. The information from this study will enable stakeholders to direct strategies of phytosanitary control toward the bitter orange crop, a preferred host of this pest in the citrus growing region of Tamaulipas, Mexico.

La tasa de participación laboral femenina (PLF) en Aguascalientes pasó de 22.5% a 49.0% entre 1990 y 2020. El objetivo de este trabajo es mostrar los resultados de identificar los factores individuales y familiares que explicarían este incremento, y de cómo éstos se comportan cuando se específica el grupo de ocupación de las mujeres; asalariadas, empresarias, por cuenta propia y trabajadoras sin pago. Se optó por un modelo Probit-bivariado, para calcular la probabilidad conjunta de incorporarse al mercado laboral y a su vez la probabilidad de cada grupo. Se utilizó la Encuesta Nacional de Ocupación y Empleo (ENOE) del primer trimestre del 2023. De acuerdo a los resultados hay cambios importantes en el perfil de las mujeres activas según su posición en la ocupación.

Sugarcane (Saccharum spp.) is a crop of great industrial and alimentary importance, essential for the production of numerous products. Given its significance, genetic improvement programs exist that involve a rigorous study process, from material selection to the development of new varieties, requiring at least seven selection phases. This study modeled the growth curve of the sucrose percentage (SP) in 33 hybrids and six control varieties (MEX 69-290, ITV 92-1424, CP 72-2086, COLMEX 94-8, COLMEX 95-27, RB 85-5113) during the plant and ratoon periods in the experimental fields of the Melchor Ocampo Sugar Mill, Jalisco, Mexico. For clustering the materials, k-means, k-medoids, and Density-based spatial clustering of applications with noise (DBSCAN) algorithms were used, considering four maturity types among the control varieties. The DBSCAN algorithm proved to be the most effective, as the means between groups were not statistically equal. The hybrids identified as candidates for subsequent phases due to their high SP were COSTA JAL, ATEMEX 99-48, ATEMEX 99-1, ATEMEX 99-61, MEX 70-486, MEX 80-1521, ITSAMEX 07-44814, ITSAMEX 06-6395, and ITSAMEX 07-1903. These results are crucial for improving the productivity and sustainability of the crop, with significant implications for the sugar industry.