RESUMEN
Greater cover crop biomass is expected to result in a favorable microhabitat for beneficial arthropods. Natural Resources Conservation Service (NRCS) cover crop termination guidelines are based on the cash crop planting date. Therefore, a delay in cash crop planting could result in greater cover crop biomass. However, studies on delays in cash crop planting and greater cover crop biomass have led to a decrease in cash crop yield. Thus, a field study was conducted in eastern Nebraska over two years to evaluate the impact of early and late corn planting dates with at-plant cover crop terminations on pest potential, beneficial arthropod activity, and agronomic parameters. To measure arthropod activity and pests in the system, pitfall traps, and corn injury assessments were performed during the early stages of corn development. A total of 11,054 and 43,078 arthropods were collected in 2020 and 2021, respectively. The results have shown no impact of the corn planting dates with at-plant cover crop termination on arthropods but identified that cereal rye cover crop supports greater Araneae activity while its alternative prey varied when compared to the no-cover treatment. Significant yield penalties were observed when cover crop was used regardless of the corn planting dates. Pest pressure was not significant in any year, however, future research using cereal rye and different cover crop species should be used in this system with an artificial infestation of a pest to be able to evaluate the trade-offs between possible cash crop yield reductions and potential biological control of pests.
Asunto(s)
Artrópodos , Animales , Grano Comestible , Zea mays , Secale , Agricultura/métodosRESUMEN
Soybean gall midge, Resseliella maxima Gagné, was recently identified as a new species causing significant injury to soybean and is currently found in 164 counties across 7 midwestern states (NE, IA, SD, MN, MO, ND, and KS). Infestation of soybean begins in late spring, when adults emerge from last year's soybean field. Infestation of a new soybean crop depends on the presence of fissures which start to form at the base of the soybean plant around the V2 stage. Field observations indicate that these fissures are only present below the cotyledonary nodes or in the area within 3-5 cm above the soil surface. To determine the importance of these fissures for R. maxima infestation and plant injury, hilling or the movement of the soil to cover the base of soybean plants at the V2-V3 stage was compared with the standard practice (no-hilling). Field studies were conducted at 3 sites in east-central Nebraska during the 2021 growing season. The results showed a significant reduction in the frequency of infested plants, larval number per plant, and plant injury for hilled compared to no-hill treatment. This reduction in the presence of larvae and plant injury corresponded with a significantly greater yield for hilled compared to the no-hill treatment. These results highlight the importance of fissures on soybean for R. maxima adult infestation as well as the potential for hilling to be used as a management strategy for R. maxima.
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Dípteros , Animales , Glycine max , Larva , Suelo , NebraskaRESUMEN
BACKGROUND: Alopecia areata (AA) is associated with negative impacts on the quality of life (QoL). Data on this impact are lacking for Canadian patients and their caregivers. OBJECTIVE: This study aims to investigate the burden of AA on Canadian patients and their caregivers. METHODS: We created 4 online surveys for patients 5-11 years old, 12-17 years old, and ≥18 years old and for caregivers of children (<18 years old) with AA. These were disseminated through the Canadian Alopecia Areata Foundation (CANAAF) website and to dermatologists across Canada. RESULTS: In total, 115 adult patients (n=100, 87%, female), 14 pediatric patients (n=13, 92.9%, female), and 15 caregivers completed the surveys online. The majority (n=123, 95%) of patients felt uncomfortable or self-conscious about their appearance. Camouflaging hair loss with hats, scarves, and hairpieces was a common practice for 11 (78.6%) pediatric and 84 (73%) adult patients. Avoidance of social situations was reported by 8 (57.1%) pediatric and 75 (65.2%) adult patients. Constant worry about losing the achieved hair growth was a concern for 8 (57.1%) pediatric and 75 (65.2%) adult patients. On a scale of 1-5, the mean score of caregivers' own feelings of sadness or depression about their child's AA was 4.0 (SD 0.9) and of their feelings of guilt or helplessness was 4.2 (SD 1.2). The impact on the QoL was moderate for both children and adults. Based on the Adjustment Disorder New Module-20 (ADNM-20), 71 (61.7%) of 115 patients were at high risk of an adjustment disorder. Abnormal anxiety scores were recorded in 40 (34.8%) patients compared to abnormal depression scores in 20 (17.4%) patients. CONCLUSIONS: This study confirmed a significant burden of AA on Canadian patients' and caregivers' QoL.
RESUMEN
Cover crops provide a habitat for pests and beneficial arthropods. Unexpected pest pressure in a cover-crop-to-corn system can occur and result in increased use of insecticides. Eight site-years of on-farm field studies were conducted in 2019, 2020, and 2021. The objective of the study was to evaluate the impact of insecticide timing relative to cover-crop termination on arthropod activity in a cover-crop-to-corn system. The treatments consisted of (i) glyphosate to terminate the cover crop, (ii) glyphosate and pyrethroid tank mix to terminate the cover crop, and (iii) glyphosate to terminate the cover crop and pyrethroid application 25 days after the termination. Arthropod activity was measured with pitfall traps before and at each treatment application. A total of 33,316 arthropods were collected. Total arthropods, Collembola, and Aphididae were the only taxa reduced with an insecticide application. The other arthropod taxa were mainly influenced by the sampling period. No significant pest pressure occurred at any site-year. Insecticide applications are not generally needed in a cover-crop-to-corn system. Scouting for pests and applying strategies only when necessary is crucial to conserve potentially beneficial arthropods in the system.
RESUMEN
Relative to fallow-cash crop rotations, the addition of a cover crop can contribute to greater plant diversity and has the potential to conserve predatory arthropods. The transition of arthropods from a cover crop to a subsequent cash crop depends on several factors, such as cover crop biomass production and weather conditions. Information about the effect of cover crop planting and termination dates on arthropods in a subsequent corn system is limited. A two-year field study was conducted in Nebraska in 2018/2019 and 2019/2020 to evaluate the impact of cover crop planting and termination dates as a source for arthropods in the subsequent corn. A total of 38,074 and 50,626 arthropods were collected in the first and second year, respectively. In both years, adding a grass cover crop increased predatory arthropods but reduced yield in follow corn crop. Of the arthropods collected, Carabidae and Araneae had greater activity with cover crop biomass increments, whereas Collembola and Acari activity only increased in treatments with little or no cover crop biomass. Insect pest pressure was not significant in any treatment for either year. A cover crop planted in mid- or late-September and terminated at corn planting was identified as the best management strategy to maximize cover crop biomass, increase predator activity, and modify predator-prey dynamics. The results of this study provide growers with a cover crop management strategy to maximize cover crop biomass, beneficial arthropod activity, and potentially minimize insect pest problems; however, corn Zea Mays (L.) grain yield was reduced as cover crop biomass increased.
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Artrópodos , Zea mays , Agricultura/métodos , Animales , Biomasa , Producción de Cultivos/métodos , Estaciones del AñoRESUMEN
This article describes the discovery of a series of potent inhibitors of Polo-like kinase 1 (PLK1). Optimization of this benzolactam-derived chemical series produced an orally bioavailable inhibitor of PLK1 (12c, MLN0905). In vivo pharmacokinetic-pharmacodynamic experiments demonstrated prolonged mitotic arrest after oral administration of 12c to tumor bearing nude mice. A subsequent efficacy study in nude mice achieved tumor growth inhibition or regression in a human colon tumor (HT29) xenograft model.