Search

Simple Summary: Citrus production worldwide is threatened by the bacterium Liberibacter spp. Fagen and its vector Diaphorina citri Kuwayama. In the absence of an effective method against the bacteria, management plans are directed towards the vector. However, management strategies such as chemical control have presented difficulties in controlling the insect. Therefore, the application of new control techniques, such as nanoparticles by green synthesis, emerges as a promising control alternative. To address this issue, the objective of this study was to evaluate silver nanoparticles by green synthesis against D. citri nymphs in the laboratory and greenhouse. The results show that the nanoparticles achieved up to 100% mortality in the laboratory and 80% in the greenhouse. These results demonstrate the effectiveness of silver nanoparticles as a potential control method for the insect. Diaphorina citri Kuwayama (Hemiptera: Liviidae) is a vector of Liberibacter asiaticus Jagoueix et al. and Liberibacter americanus Teixeira et al., causal agents of the critical yellow dragon disease or Huanglongbing (HLB), which affects citrus production worldwide. Recently, green synthetic nanoparticles have emerged as a potential alternative to control of agricultural insect pests. The insecticide effect of silver nanoparticles (AgNPs) on 2nd instar nymphs of D. citri under laboratory and greenhouse conditions was evaluated. Mortality was recorded 24, 48, and 72 h after application on D. citri nymphs under both laboratory and greenhouse conditions. The laboratory results showed that AgNPs caused 97.84 and 100% mortality at 32 and 64 ppm, respectively, 72 h after treatment. In the greenhouse, AgNPs caused 78.69 and 80.14% mortality using 64 and 128 ppm 72 h after application. This research is the first to evaluate the green synthesis AgNPs on D. citri and are a promising strategy to control the pest. [ABSTRACT FROM AUTHOR]

Damage by fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), causes sorghum Sorghum bicolor (L.) Moench (Poaceae) yield loss and decreases crop value, causing great economic losses to growers. Foliar damage was evaluated with natural infestation by fall armyworms in experimental lines of sorghum. Foliar damage was analyzed using a Davis scoring scale and grain yield was evaluated 120 days after planting. Data were processed with analysis of variance (ANOVA) and correlation using Spearman test with R software. ELS 254-1 yielded most (9.92 tons/ha) and a value of 1 on Davis scale with less foliar damage with 19.75%; ELS-154 yielded least (2.45 tons/ha) and had most foliar damage (25.93%) and a value of 2 on the Davis scale. All experimental lines were managed the same during the crop cycle. Outstanding lines ELS-18, ELS-103-1, ELS-143-1, ELS-197, ELS-203-3, ELS-284, and Negro-Soruyo had less damage by fall armyworms and good yield and could be a source of useful germplasm in breeding programs. Sorghum lines resistant to fall armyworms that yield well in regions in which they are better such as in southeastern Coahuila, will result in a less cost to growers by less need to control the pest and greater economic benefit. El daño causado por el gusano cogollero, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) causa pérdidas de rendimiento en sorgo Sorghum bicolor (L.) Moench (Poaceae) y disminuye el valor del cultivo, causando grandes pérdidas económicas al productor. El daño foliar se analizó bajo infestación natural de gusano cogollero en líneas experimentales de sorgo utilizando la escala de puntuación de Davis, y el rendimiento de grano se evaluó 120 días después de la siembra. Los datos se procesaron con un análisis de varianza (ANOVA) y una prueba de correlación con el software R utilizando la prueba de Spearman. El ELS 254-1 tuvo el mayor rendimiento (9.92 tons/ha) y un valor de 1 en la escala de Davis con menor daño foliar con 19.75%. ELS-154 presentó el menor rendimiento (2.45 tons/ha) y el mayor daño foliar con 25.93% con un valor de 2 en la escala de Davis. Todas las líneas experimentales recibieron el mismo manejo durante el ciclo de cultivo. Otras líneas sobresalientes ELS-18, ELS-103-1, ELS-143-1, ELS-197, ELS-203-3, ELS-284, y Negro-Soruyo, también tuvieron bajo daño por gusano cogollero y buen rendimiento y podrían ser una fuente de germoplasma útil en los programas de mejoramiento. Las líneas de sorgo que muestran resistencia al gusano cogollero y produzcan alto rendimiento en regiones en las que estos materiales se desempeñan mejor como en el sureste de Coahuila, resultarán en un menor costo para los productores, al tener un control más efectivo de esta plaga y mayores beneficios económicos. [ABSTRACT FROM AUTHOR]

One of the important domestic insects that transmit many pathogens to the environment is the Periplaneta Americana. The control methods of this insect are often ineffective and have caused resistance in these insects. The purpose of the present study was to investigate the effects of contact and feeding lethality of titanium nanoparticles on Periplaneta Americana. In this study, different concentrations of nanoparticles were prepared for oral and contact treatments of Periplaneta Americana. Periplaneta Americana was treated by contact and oral methods with different concentrations of titanium oxide nanoparticles with three repetitions. The average percentage of insect mortality in different groups was compared by one-way analysis of variance and Duncan's test. Also, the average percentage of insect mortality on different days in each group was compared by analysis of variance with repeated observations. Oral treatment of Periplaneta Americana was more effective than contact treatment in concentrations of 15 and 21 percent on all days, but contact treatment was more effective than oral treatment on all days except the seventh day at a concentration of 25 percent. In general, oral treatment was more effective than contact treatment. With increasing doses and the passage of time, the mortality percentage of Periplaneta Americana due to contact and oral treatment with titanium dioxide nanoparticles increased significantly. According to the obtained results, the use of different nanoparticles, including titanium dioxide nanoparticles, can create a significant effect in controlling the Periplaneta Americana as a new method along with the previous methods. [ABSTRACT FROM AUTHOR]

The objective of this research was the morphomolecular identification of species of the genus Fusarium associated with native and commercial maize genotypes in municipalities of Puebla and Morelos, Mexico, as well as to describe the socioeconomic and cultural importance of maize cultivation. Fusarium species were isolated from grains and stem cuttings with purple, brown, and dark brown pigmentations. They were identified morphomolecularly by using taxonomic keys and the Dinocapture 2.0 software, and by DNA extraction by the CTAB method and amplification of the ITS1 and ITS4 region by PCR. Four species were identified: Fusarium equiseti, Fusarium verticillioides, Fusarium incarnatum and Fusarium napiforme with an identity greater than 98 %. The genotypes with the highest incidence of Fusarium spp. were: Pioneer 30F35 in San Miguel, Teotlalco, Puebla by F. verticillioides (A2). The genotypes with the lowest incidence were: Shark from Tetelilla, Morelos by F. incarnatum (A1), F. verticillioides (A6) and F. napiforme (A7). Maize is the main food in many locations in Mexico, however, due to the high consumption of this grain and its derivatives, as well as the high consumption of meat presumably fed with this grain, it could represent a route of ingestion of mycotoxins. [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.)

La mosca blanca de los invernaderos, Trialeurodes vaporariorum, es una plaga polífaga que provoca pérdidas económicas. Su manejo se basa en la aplicación constante de insecticidas sintéticos. El desarrollo de cultivares resistentes a insectos vectores, representa una alternativa que puede reducir los niveles de infestación e infección. Además, es una estrategia que puede implementarse eficientemente dentro de un sistema de manejo integrado. El objetivo de esta investigación fue evaluar el efecto de antibiosis y antixenosis de tres variedades de tomate en T. vaporariorum. El asentamiento, la oviposición y el desarrollo de ninfas se evaluaron en condiciones de laboratorio e invernadero. La variedad silvestre Solanum habrochaites fue la menos atractiva para los adultos en las pruebas de antixenosis, además de expresar un bajo desarrollo en las ninfas del insecto en los ensayos de antibiosis en comparación con S. lycopersicum cv Floradade. La especie S. pimpinellifolium demostró resistencia media en ambas evaluaciones. El alto nivel de resistencia de LA0407 puede servir como base para el mejoramiento genético del tomate, centrándose en el desarrollo de variedades resistentes. Greenhouse whitefly, Trialeurodes vaporariorum, is a polyphagous pest that causes economic loss. Management is based on constant application of synthetic insecticides. Development of cultivars resistant to insect vectors is an alternative that can reduce infestation and infection levels. In addition, it is a strategy that may be implemented effectively as part of an integrated management system. The objective of this report was to evaluate the effect of antibiosis and antixenosis of three tomato varieties on T. vaporariorum. Under laboratory and greenhouse conditions, settlement, oviposition, and nymph development were evaluated. Wild variety Solanum habrochaites was least attractive to adults in antixenosis tests, demonstrating low growth in insect nymphs in antibiosis tests compared to S. lycopersicum cv. Floradade. Variety S. pimpinellifolium showed moderate resistance in both evaluations. The high level of resistance of LA0407 can serve as a base for tomato breeding, focusing on development of resistant cultivars. [ABSTRACT FROM AUTHOR]

Copyright of Investigación y Ciencia de la Universidad Autónoma de Aguascalientes is the property of Universidad Autonoma de Aguascalientes, Direccion General de Investigacion y Posgrado 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.)

Sugarcane aphid, Melanaphis sacchari Zehntner (Hemiptera: Aphididae), can greatly reduce yield potential of sorghum, Sorghum bicolor (L.) Moench. Sugarcane aphid and its natural enemies were sampled in pesticide-free fields at Altamira, Tamaulipas, Mexico, during a 2-year period. Seven species of predators identified were: Orius sp. Wolff (Hemiptera: Anthocoridae), Cycloneda sanguinea (L.), Hippodamia convergens Guérin-Méneville, and Scymnus sp. Kugelann (Coleoptera: Coccinellidae); Chrysoperla sp. Steinmann (Neuroptera: Chrysopidae); and Eosalpingogaster sp. Hull, and Eupeodes sp. Osten-Sacken (Diptera: Syrphidae). Five parasitoid species associated with the pest were Pachyneuron aphidis Bouché and Pachyneuron muscarum L. (Hymenoptera: Pteromalidae), Lysiphlebus testaceipes Cresson (Hymenoptera: Braconidae), and Aphelinus mali Haldeman and Aphelinus varipes Förster (Hymenoptera: Aphelinidae). Pachyneuron spp. parasitized 68.25%, while other parasitoids parasitized 6.44% of the aphids sampled. This research furthers understanding of already existing and ongoing parasitism/predation and enriches knowledge of natural enemies that can be used as biological control agents against M. sacchari. A. mali, P. aphidis, and P. muscarum were reported as parasitoids of M. sacchari. [ABSTRACT FROM AUTHOR]

The safflower Carthamus tinctorius L. it is a crop that has been adopted by a large number of producers, particularly in the Northwest of the country, due to its great adaptability and its little water requirement, due to the great demands presented by the oilseed industry in the country. Since the 1970s it has been worked to generate materials that are highly productive, with good percentage and qualityof oil and with characteristics of resistance to the main diseases present in the region (false mildew and leaf rust). For this reason, the objective of this work was to evaluate the behavior of the elite safflower lines generated by the genetic improvement program in the region (23 oleic and 1 linoleic). These lines were established during cycles 2017-2018 and 2018-2019. Its agronomic behavior was evaluated under the present conditions of the Yaqui Valley. Oleic lines were found that surpassed witnesses Ciano ol and Chey ol, varieties that are widely sown in the region. In addition, it was found that the linoleic type line had better agronomic characteristics, production and oil content than witness RC-1002 which leads to the conclusion that within the evaluated lines there are potential materials to be released as a variety. [ABSTRACT FROM AUTHOR]