David Heriberto Noriega-Cantú

Resumen. Variabilidad genética del ajonjolí1 frente al daño causado por tres especies de Diabrotica2 en Guerrero, México El ajonjolí es un cultivo de importancia agrícola debido a su alto contenido de aceite y proteína, y a su amplia aplicación en las industrias alimentaria, cosmética y farmacéutica. El objetivo de este estudio fue evaluar la resistencia en 50 genotipos de ajonjolí de grano blanco al daño causado por Diabrotica balteata, D. virgifera y D. decempunctata. La intensidad del daño fue generalmente menor durante la primera evaluación y aumentó en las evaluaciones posteriores. Veintiocho genotipos presentaron un nivel de daño 3, con un rango entre 3.1 y 3.9 (<20%), destacando Tacupa y Eva como los genotipos con los niveles de daño más bajos. Con estos resultados se puede iniciar un programa de mejoramiento genético con énfasis en la resistencia de líneas de ajonjolí que resistan el ataque de Diabrotica.

The objective of this research was to identify the insects associated with damage to acahual plants. During August and September 2024, sampling was carried out in Tepalcingo, Morelos, and Iguala de la Independencia, Guerrero, Mexico, on acahual plants (Tithonia tubaeformis) with signs of defoliation. Plant structures and whole plants were collected, as well as adult insects associated with the damage, which were preserved in 70% ethanol. Weed identification was carried out through morphological comparisons with CONABIO; insect identification was performed through morphological comparison and stereoscopic microscopy. For this purpose, one specimen per collection site was mounted separately on sample slides, where they were coated with graphite, for observation with a JEOL IT300-LV SEM stereomicroscope, equipped with a Quantax EDS detector: Xflash 6|30. The morphological characteristics of the plants allowed the identification of the species Tithonia tubaeformis (Asteraceae), and regarding the insect, Calligrapha (Zygogramma) signatipennis (Coleoptera: Chrysomelidae) was identified, whose damage to Tithonia tubaeformis was moderate to severe in some plants. This damage was specific to this species, suggesting that Calligrapha (Zygogramma) signatipennis could have potential as a biological control agent for the management of Tithonia tubaeformis. It is worth noting that this species has a greater feeding preference for acahual plants that are in the vegetative stage, where it can cause good control of this weed.

The guacimo (Guazuma ulmifolia Lam.) is a tree used for several purposes in agroforestry. However, phytophagous mites have great impact on guacimo, creating leaf galls. The objective of this study was to taxonomically identify mites found in galls of G. ulmifolia at the Tepalcingo community, Morelos, Mexico. Random samples of malformed leaves and galls were collected during field trips, and taxonomic keys were used to identify the mites. Subsequently, the galls were dissected, and identity of the samples was determined with the aid of a stereoscope. The phytophagous mites belonged to the Eriophyidae family and are an invasive pest of guacimo trees. Future studies should focus on finding effective biological control agents and using molecular techniques for more accurate identification.

Mango anthracnose in mango in the tropical and subtropical regions of Mexico is a disease that induces serious economic losses, caused by Colletotrichum gloesporioides. The objective of this research was to determine the efficiency of integrated management for anthracnose control and to identify the critical moment for disease management. The work was carried out on cv. ‘Ataúlfo’, in Guerrero, Mexico, in three production cycles. The identification of the pathogen was confirmed and during a period of 11 months the abundance of spores in the canopy of the trees was examined. Three treatments were evaluated: integrated management with severe pruning (MIM-Pruning), integrated management without severe pruning (MIM) and Control treatment. The climate was conducive to the development of the disease (>80% incidence). The greatest increase in spores, with 65.9 to 84.1 spores/week, was observed during summer vegetative growth, in the phase of flowering and fruit set on the rachis, with its subsequent decrease in fruit growth. The MIM-Pruning and MIM treatment showed consistent results of less area under the disease curve progress (AUDCP), in foliage and flowering, causing a greater definitive fruit set per inflorescence and marketable fruits per tree with respect to the Control (P ≤0.05). Field pathogen population management should begin with the spraying of fungicide products in the summer vegetative growth phase and before the full flowering stage. Pruning is a practice that should be included in anthracnose management.

Background. Mexico has a great diversity of chili peppers, especially in C. annuum L., which includes local morphotypes that have been little studied. Apaxtleco chili pepper is only found in Guerrero State, Mexico, and it is important in Apaxtla region due to economic resources it generates, and because it is used in preparation of typical mole in this region; however, its morphological diversity has not been described and this visualizes the state of this plant genetic resource to define use and conservation strategies. Objective. To analyze and describe morphological diversity of a group of Apaxtleco chili pepper populations, identify characteristics that most support its diversity and establish similarity relationship between the populations studied. Methodology. Twenty-four populations of apaxtleco chili pepper collected from Apaxtla de Castrejón, Guerrero were evaluated under randomized complete block experimental design, with four replications. The evaluation was carried out under greenhouse conditions at Tuxpan Unit of Autonomous University of Guerrero. Sowing was carried out in July 2020 in polyethylene pots with 16 L capacity. Fifty-nine morphological variables from IPGRI descriptors for Capsicum were recorded, and variance, discriminant, principal components (CP) and conglomerated analysis were performed by SAS V9.3 software. Results. Statistical significant differences were found in 72.9 % of variables registered and seventeen were selected by its contribution to variation according discriminant analysis, which were mostly fruits characteristics. In CP, with the first six, 76 % of total morphological variation was explained; length fruit and pedicel, width seed, weight fruit per plant, color of fruit at intermediate stage, number fruits per plant, width fruit, fruit and seed texture, filament color, number seeds per fruit and shape fruit appendage had greater contribution to total morphological diversity and were useful to differentiate populations under study. As well, four groups of apaxtleco chili pepper with different fruit, vegetative and flower characteristics were identified, however, it was possible to group them by shape and texture of fruits. Implications. Contribute to description of diversity of local populations of apaxtleco chili, native to Guerrero, Mexico, and that allows the establishment of use and conservation mechanisms for food security. Conclusion. Morphological diversity of native apaxtleco chili of Guerrero is presented mainly in fruit characteristics and lesser degree in vegetative and seed traits, which were useful to explain greater total variation in this local chili. The shape and texture fruits were important characteristics in grouping.

Thirty accessions of cotton (Gossypium) in the INIFAP genebank in the Iguala Experimental Field were analyzed for resistance to eriophyid mites. Vegetative structures such as leaves and petioles and reproductive structures such as the bract calyx with galls were collected from cotton plants. Galls were cut into cross section to locate mites; taxonomic keys were used to identify the mites. Damage to accessions of cotton was evaluated on a scale of six classes. Damage by eriophyid mites was analyzed with PROC RANK, subjecting it to analysis of variance with PROC GLM, and mean comparison by Tukey (P = 0.05) using statistical software SAS® 9.2. Eriophyidae was reported associated with formation of galls in cotton. Severity of damage was 0 to 85%, but cotton accessions TOA-06, FZ-06, GOS-16, GOS-34, TOA-09, TOA-02, GOS-17, TOA-04, and TOA-05 were resistant. More studies of biology and ecology and molecular analysis are needed to better understand and develop management strategies against mites in cotton.

Background: Roselle calyx spot (MCJ) causes losses of 80% of the yield of this crop. Objective: To know the geographical distribution of the leaf and calyx disease of the roselle in the producing localities and municipalities of the state of Guerrero. Methodology: The recognition area included the Costa Chica region (Ayutla de los Libres, Tecoanapa, San Marcos and Acapulco de Juárez), Costa Grande (Atoyac de Álvarez and Coyuca de Benítez) and the North region (Copalillo). The delimitation of the commercial plots considered a distance> 10 km, for a sampling in five of golds, evaluating the incidence and severity of MCJ. The information was integrated into a database of geographic information systems and the spatial pattern was analyzed. The variables were analyzed in random blocks, with five repetitions, under the procedure with proc rank and an analysis of variance proc glm, the separation of means was used by the Tukey-Kramer procedure and Spearman's linear correlation coefficients were calculated. Results: The disease has a differential geographical distribution, the highest incidence (> 75%) in calyx occurred in the municipalities of Tecoanapa and Ayutla, however, its presence in the leaves can increase the incidence in calyx in Acapulco, San Marcos, Copalillo and Coyuca de Benítez. The highest severity index was presented in Tecoanapa with 2.87, showing differences with Ayutla, Acapulco and San Marcos with 2.24, 2.06 and 1.04 respectively (p <0.05). Atoyac and Copalillo only had leaf spots and Coyuca de Benítez the disease was not detected. The Tecoanapa and Coneja genotypes had leaf and calyx spotting values of 2.85 and 2.17 respectively, with significant differences with the Criollo, Jersey and Sudan genotypes with low values of 1.59, 0.75 and 0.31 respectively (p 100 m with 2.09 and 0-18 m with 0.93 (p <0.05). The severity of the MCJ was correlated with the altitude, genotypes and producing municipalities. Implications: The disease distribution maps made it possible to identify municipalities with higher risk, genotypes and altitudes with higher and lower incidence and severity of MCJ. Conclusions: The study shows that the MCJ in Guerrero is influenced by the genotypes and altitudes of the sowing areas, which causes a diverse incidence and severity of the disease among producing municipalities.

One of the limitations in agricultural production in the State of Guerrero is the various events of meteorological disasters, with the case of recurrent drought, hurricane winds, high rainfall that cause floods and very high daytime temperatures that directly affect annual crops (corn, beans and sorghum) and perennials (mango, lemon, avocados). In the entity there is little accurate and timely agroclimatic information that serves as a determining factor in the decision-making process of production processes. The present study has the purpose of developing a prototype of low-cost agrometeorological station. The data can be monitored via the Internet 24 hours a day, from the climate variables, such as: environmental temperature, relative humidity, rainfall, solar and ultraviolet radiation, wind speed and direction. With the storage of these climatological data, information will be obtained that contributes to the prevention of diseases and pests in the cultivation of corn, fruit trees and vegetables of economic importance. Reason for which the National Institute of Forestry, Agriculture and Livestock Research and the Technological University of the North Region of Guerrero, are joining forces in the development of a prototype of agrometeorological station.

The National Institute of Forestry, Agriculture and Livestock Research, Iguala Experimental Field and the Technological University of the North Region of Guerrero, are joining their knowledge in the scientific and technological field with the purpose of developing collaborative projects. In the State of Guerrero, there is a lack of accurate and timely agroclimatic information that serves as a determining factor in decision-making in productive processes. The purpose of this study is to develop a website and a mobile application, where the information issued by the prototype of agrometeorological station can be accessed. The data will be entered into a database on the website and will be stored every 10, 15 or 30 minutes of the climate variables, such as: temperature, relative humidity, precipitation, solar radiation, leaf moisture, speed and direction of the wind. The mobile application will allow to consult historical and real-time weather data. This will result in better control of environmental information so that producers in the cultivation of corn, fruit and vegetables can prevent and avoid pests and diseases of their crops.