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Hymenopteran parasitoid complex and fall armyworm: a case study in eastern India

Tapamay Dhar PRATEEK MADHAB BHATTACHARYA Mahesh Gathala Alison Laing (2024, [Artículo])

Fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) has significantly affected maize crop yields, production efficiency, and farmers’ incomes in the Indian Eastern Gangetic Plains region since it was first observed in India in 2018. A lack of awareness by maize growers of the appropriate selection, method, and timing of insecticide application not only creates a barrier to sustainable FAW control but also contributes to increased environmental pollution, reduced human health and increased production costs. We demonstrated that FAW inflicted the most damage in early whorl growth stage of maize, regardless of whether chemical insecticides were applied. FAW egg masses and larvae collected from maize fields in which no insecticides had been sprayed showed high parasitism rates by parasitoid wasps; in contrast fields that had been sprayed had much lower rates of parasitism on FAW. Ten hymenopteran parasitoids were observed in maize fields across the study region, suggesting a diversity of natural methods to suppress FAW in maize at different growth stages. These included two FAW egg parasitoids and eight FAW larval parasitoids. Microplitis manilae Ashmead was the most abundant FAW larval parasitoid species, and Telenomus cf. remus was the dominant FAW egg parasitoid species. Endemic FAW parasitoids such as those observed in this study have great potential as part of a sustainable, cost-effective agroecological management strategy, which can be integrated with other methods to achieve effective control of FAW.

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA FALL ARMYWORMS MAIZE INSECTICIDES INSECT CONTROL

Metabolites Profile of Extracts and Fractions of Erythroxylum mexicanum Kunth by UHPLC-QTOF-MS/MS and its Antibacterial, Cytotoxic and Nitric Oxide Inhibitory Activities

LAURA PATRICIA ALVAREZ BERBER MARIA DE LOS ANGELES RAMIREZ CISNEROS (2024, [Artículo])

The present study shows the untargeted metabolite profiling and in vitro antibacterial, cytotoxic, and nitric oxide (NO) inhibitory activities of the methanolic leaves extract (MLE) and methanolic stem extract (MSE) of Erythroxylum mexicanum, as well as the fractions from MSE. Using ultra-high performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry (UHPLC-QTOF-MS/MS), a total of 70 metabolites were identified; mainly alkaloids in the MLE, while the MSE showed a high abundance of diterpenoids. The MSE fractions exhibited differential activity against Gram-positive bacteria. Notably, the hexane fraction (HSF) against Streptococcus pyogenes ATCC 19615 (MIC=62.5 µg/mL) exhibited a bactericidal effect. The MSE fractions exhibited cytotoxicity against all cancer cell lines tested, with selectivity towards them compared to a noncancerous cell line. Particularly, the HSF and chloroform fraction (CSF) showed the highest cytotoxicity against prostate cancer (PC-3) cells, with IC50 values of 19.9 and 18.1 µg/mL and selectivity indexes of 3.8 and 4.2, respectively. Both the HSF and ethyl acetate (EASF) fractions of the MSE inhibited NO production in RAW 264.7 macrophages, with NO production percentages of 50.0% and 51.7%, respectively, at a concentration of 30 µg/mL. These results indicated that E. mexicanum can be a source of antibacterial, cytotoxic, and anti-inflammatory metabolites.

BIOLOGÍA Y QUÍMICA QUÍMICA MS analysis • diterpenoids • biological activities

Control biológico del lirio acuático en México: primera experiencia exitosa con neoquetinos en distritos de riego: volumen I: distrito de riego 010 Culiacán-Humaya, Sinaloa, distrito de riego 074 Mocorito, Sinaloa, distrito de riego 018 colonias Yaquis, Sonora

OVIDIO CAMARENA MEDRANO (2013, [Libro])

Los objetivos de esta investigación han sido: documentar las experiencias en el control biológico del lirio acuático en la infraestructura de riego en seis distritos de riego de México; dejar constancia de la eficacia y eficiencia de los neoquetinos como agentes de control biológico del lirio; demostrar la factibilidad de mantener sin problema de lirio, en forma permanente, cualquier cuerpo de agua del país mediante estre control biológico; y sensibilizar a las autoridades, técnicos y productores sobre las bondades del control biológico del lirio acuático en nuestro país, principalmente en los distritos de riego.

Lirio acuático Distritos de riego Control biológico Sinaloa Sonora CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

Unanswered questions and unquestioned answers: the challenges of crop residue retention and weed control in Conservation Agriculture systems of southern Africa

Christian Thierfelder Blessing Mhlanga Hambulo Ngoma Paswel Marenya Md Abdul Matin Adane Tufa (2024, [Artículo])

Production and utilization of crop residues as mulch and effective weed management are two central elements in the successful implementation of Conservation Agriculture (CA) systems in southern Africa. Yet, the challenges of crop residue availability for mulch or the difficulties in managing weed proliferation in CA systems are bigger than a micro-level focus on weeds and crop residues themselves. The bottlenecks are symptoms of broader systemic complications that cannot be resolved without appreciating the interactions between the current scientific understanding of CA and its application in smallholder systems, private incentives, social norms, institutions, and government policy. In this paper, we elucidate a series of areas that represent some unquestioned answers about chemical weed control and unanswered questions about how to maintain groundcover demanding more research along the natural and social sciences continuum. In some communities, traditional rules that allow free-range grazing of livestock after harvesting present a barrier in surface crop residue management. On the other hand, many of the communities either burn, remove, or incorporate the residues into the soil thus hindering the near-permanent soil cover required in CA systems. The lack of soil cover also means that weed management through soil mulch is unachievable. Herbicides are often a successful stopgap solution to weed control, but they are costly, and most farmers do not use them as recommended, which reduces efficacy. Besides, the use of herbicides can cause environmental hazards and may affect human health. Here, we suggest further assessment of the manipulation of crop competition, the use of vigorously growing cover crops, exploration of allelopathy, and use of microorganisms in managing weeds and reducing seed production to deplete the soil weed seed bank. We also suggest in situ production of plant biomass, use of unpalatable species for mulch generation and change of grazing by-laws towards a holistic management of pastures to reduce the competition for crop residues. However, these depend on the socio-economic status dynamics at farmer and community level.

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA INTEGRATED CROP-LIVESTOCK SYSTEMS CROP RESIDUES ZERO TILLAGE SOCIAL NORMS SUSTAINABLE INTENSIFICATION WEED CONTROL

Control de malezas acuáticas en México

MARICELA MARTINEZ JIMENEZ MARIA DEL PILAR SALDAÑA FABELA ERIC DANIEL GUTIERREZ LOPEZ (2003, [Artículo])

Las malezas acuáticas continúan constituyendo un problema en el país, por lo que los intentos realizados para su combate, ya sea en forma manual, mecánica o química, sólo han tenido resultados temporales a un costo elevado, pues las semillas de la flor que se depositan en los sedimentos son la fuente de futuras re-infestaciones. En este sentido, el Instituto Mexicano de Tecnología del Agua (IMTA) ha investigado soluciones sustentables y con menos impacto al medio ambiente, encontrando que el uso de agentes biológicos podría constituir una solución al problema. El artículo detalla la experiencia del IMTA en el uso de artrópodos y hongos específicos para su desarrollo como bioherbicidas para controlar el crecimiento del lirio acuático.

Malezas acuáticas Control de malezas Control biológico Bioherbicidas BIOLOGÍA Y QUÍMICA