ABSTRACT
BACKGROUND: Transgenic Bt technology in soybean, with plants expressing Cry1Ac, has been adopted as an insect pest management tool. It was first adopted in large areas of South America and Asia in 2013. The risk of resistance in target pests to this technology demands insect resistance management (IRM) programs. In Brazil, a structured refuge (area of non-Bt soybean) planted adjacent to the Bt soybean crop has been an important IRM recommendation, particularly for the primary lepidopteran defoliators Anticarsia gemmatalis (Lepidoptera: Erebidae) and Chrysodeixis includens (Lepidoptera: Noctuidae). The overall goal of this study was to validate IRM recommendations to Bt soybean. The objectives were to document the impact of soybean phenology, cultivar choice and non-Bt soybean defoliation on moth oviposition. In addition, a mark-release-recapture study estimated the dispersal capacity of these species. Five field experiments per species were performed for 3 years. RESULTS: Our results revealed an increase in A. gemmatalis and C. includens oviposition, respectively, on Bt plants as a consequence of the difference in plant growth stage at the time of oviposition. Defoliation of non-Bt plants significantly increased the oviposition preference of both moth species for Bt plants. The mark-release-recapture experiment indicated an average dispersal distance of ~300 m from the release point for A. gemmatalis, with maximum recapture at 1000 m. CONCLUSION: Overall, our findings emphasize the importance of planting synchronization of Bt soybean and the structured refuge. In addition, when operational aspects in large soybean areas challenge this recommendation, the priority should be for planting the refuge area first. This approach will minimize the impact of selective oviposition of A. gemmatalis and C. includens. © 2024 Society of Chemical Industry.
ABSTRACT
ABSTRACT The dispersion of Diceraeus melacanthus (Dallas) from soybean (first crop season) to maize (second crop season) is facilitated by the presence of weeds (e.g. Commelina benghalensis) and soybean grains on the ground. Understanding insect development and behavior on different food sources is important to develop pest management strategies. Thus, three independent experiments were conducted to study D. melacanthus nymph development, and adult preference for feeding and oviposition in different food source scenarios in the field. The first two trials studied development and food preference of D. melacanthus related to different food sources (C. benghalensis branches, moistened soybean grain + soybean seedlings, maize seedlings + C. benghalensis branches, moistened soybean grains + maize seedlings, moistened soybean grains + C. benghalensis branches, maize seedlings, as well as a standard diet). The third trial evaluated D. melacanthus oviposition preferences between the aforementioned plants. Overall, moistened soybean grains resulted in better nutritional quality, thus being crucial for D. melacanthus development, triggering faster nymph development as well as better overall adult fitness. The combination of soybean grains and maize seedlings or C. benghalensis branches showed great potential to benefit D. melacanthus, since these complementary food sources improved stink bug fitness, increasing mainly adult longevity, fecundity and egg viability. Therefore, it can be concluded that in order to reduce D. melacanthus outbreaks in second season maize, it is important to reduce soybean harvest loss (reducing, therefore, moistened soybean grain on the ground) and eliminate stink bug associated plants like C. benghalensis.
ABSTRACT
Environmental variables may markedly influence egg parasitoid performance and must be considered when choosing the best release strategy. Thus, this study aimed to investigate the effects of light, temperature, soil moisture, and precipitation on the emergence and parasitism of parasitoid releases of unprotected and encapsulated pupae. The presence of light favored the parasitism of Trichogramma pretiosum Riley, 1879, and Telenomus remus (Nixon, 1937) but did not impact the parasitism of Telenomus podisi (Ashmead, 1893). The release strategy adopted (release of encapsulated or unprotected pupae) also impacted the results. On one hand, card capsules gave protection against rainfall, limited to 10 mm regarding Tr. pretiosum, while on the other hand, card capsules led to a reduction in the number of captured adults for Te. podisi at 25°C and 30°C. Therefore, Tr. pretiosum, Te. remus, and Te. podisi can be released using both encapsulated and unprotected pupae, with advantages and disadvantages for each strategy, depending on each studied environmental variable. In addition, parasitoid pupae should be released so that the majority emerge during daylight, especially for Te. remus and Tr. pretiosum, since parasitism was greatly reduced in dark environments. Telenomus podisi is not affected by this variable as it demonstrated similar parasitism in light and dark environments.
Subject(s)
Hymenoptera , Animals , Hymenoptera/parasitology , Light , Pupa , Rain , TemperatureABSTRACT
Objetivo: analisar o sofrimento psíquico entre universitários de enfermagem no contexto da vida acadêmica. Método: pesquisa descritiva, de abordagem qualitativa, realizada com 20 universitários do último semestre de enfermagem, de uma universidade pública no Nordeste, Brasil. Os dados foram produzidos por perguntas abertas, entre março de 2016 a fevereiro de 2017, e avaliados pela análise de conteúdo. Resultados: os motivos de sofrimento psíquico foram as dificuldades de adaptação dos universitários no início do curso, conflitos durante a formação e expectativas quanto ao término da graduação. Diante disso, as consequências identificadas foram dificuldades alimentares, estresse e sintomas de depressão. Os modos de viver dos universitários são influenciados pelas vivências acadêmicas, inclusive os hábitos alimentares, excesso de trabalho e falta de lazer. Eles podem ser precursores de problemas graves de saúde, como ideação suicida. Conclusão: sugere-se ampliar estratégias de prevenção e manejo clínico na universidade articulado aos serviços de saúde mental.
Objective: to analyze the psychic suffering among nursing students in the context of academic life. Method: descriptive research, with a qualitative approach, carried out with 20 university students from the last semester of nursing, from a public university in the Northeast, Brazil. The data were produced by open-ended questions, between March 2016 and February 2017, and evaluated by content analysis. Results: the reasons for psychological suffering were the difficulties of adapting the university students at the beginning of the course, conflicts during training and expectations regarding the end of graduation. Given this, the consequences identified were dietary difficulties, stress and symptoms of depression. The way of life of university students is influenced by academic experiences, including eating habits, overwork and lack of leisure. They can be precursors of serious health problems, such as suicidal ideation. Conclusion: it is suggested to expand prevention and clinical management strategies at the university linked to mental health services.
Objetivo: analizar el sufrimiento psicológico en estudiantes de enfermería en el contexto de la vida académica. Método: investigación descriptiva, con enfoque cualitativo, realizada con 20 estudiantes universitarios del último semestre de enfermería, de una universidad pública del Noreste, Brasil. Los datos se elaboraron mediante preguntas abiertas, entre marzo de 2016 y febrero de 2017, y se evaluaron mediante análisis de contenido. Resultados: los motivos del sufrimiento psicológico fueron las dificultades de adaptación de los universitarios al inicio del curso, los conflictos durante la formación y las expectativas sobre el final de la graduación. Ante esto, las consecuencias identificadas fueron dificultades dietéticas, estrés y síntomas de depresión. La forma de vida de los estudiantes universitarios está influenciada por las experiencias académicas, incluidos los hábitos alimentarios, el exceso de trabajo y la falta de ocio. Pueden ser precursores de problemas de salud graves, como la ideación suicida. Conclusión: se sugiere ampliar las estrategias de prevención y manejo clínico en la universidad vinculadas a los servicios de salud mental.
Subject(s)
Humans , Stress, Psychological , Students, Nursing , Universities , Mental Health , NursingABSTRACT
The hydroalcoholic extract of Punica granatum (pomegranate) leaves was previously demonstrated to be anti-inflammatory in a rat model of lipopolysaccharide- (LPS-) induced acute peritonitis. Here, we investigated the anti-inflammatory effects of the ethyl acetate fraction obtained from the pomegranate leaf hydroalcoholic extract (EAFPg) on the LPS-induced acute lung injury (ALI) mouse model. Male Swiss mice received either EAFPg at different doses or dexamethasone (per os) prior to LPS intranasal instillation. Vehicle-treated mice were used as controls. Animals were culled at 4 h after LPS challenge, and the bronchoalveolar lavage fluid (BALF) and lung samples were collected for analysis. EAFPg and kaempferol effects on NO and cytokine production by LPS-stimulated RAW 264.7 macrophages were also investigated. Pretreatment with EAFPg (100-300 mg/kg) markedly reduced cell accumulation (specially neutrophils) and collagen deposition in the lungs of ALI mice. The same animals presented with reduced lung and BALF TNF-α and IL-1ß expression in comparison with vehicle controls (p < 0.05). Additionally, incubation with either EAFPg or kaempferol (100 µg/ml) reduced NO production and cytokine gene expression in cultured LPS-treated RAW 264.7 macrophages. Overall, these results demonstrate that the prophylactic treatment with EAFPg attenuates acute lung inflammation. We suggest this fraction may be useful in treating ALI.
