675 research outputs found

    Impact of climate change on insect pests, plant chemical ecology, tritrophic interactions and food production

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    Climate change is a major concern for agriculture globally. Dynamic climatic parameters including increased temperature and carbon dioxide have greatly affected crop production. As a consequence of climatic uncertainties, new insect pests have emerged, the crop cultivation practices have changed, and drought and floods have created havoc around the globe. Besides, plant and insecticidal resistance against insects and diseases has got compromised, the diversity and abundance of arthropods has changed, geographical ranges of insect pests have extended far beyond their existing limits and new biotypes have evolved. All these have led to the reduced efficacy of crop protection technologies, huge crop losses, thereby, food insecurity. Although concerted efforts have been made and simulation models have been developed to mitigate the climate change effects on plants, still, most simulation models fail to account for losses due to pests, weeds and diseases. In addition, the monitoring data of insect pests are not available in most of the developing countries and the software models developed for prediction analysis are not effective against insect- pests. This review highlights the possible impacts of climate change on phytophagous insects, chemical ecology, and plant pest interactions leading to food insecurity and the strategies thereof

    Induced resistance to Helicoverpa armigera through exogenous application of jasmonic acid and salicylic acid in groundnut, Arachis hypogaea

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    Background Induced resistance to Helicoverpa armigera through exogenous application of jasmonic acid (JA) and salicylic acid (SA) was studied in groundnut genotypes (ICGV 86699, ICGV 86031, ICG 2271 and ICG 1697) with different levels of resistance and the susceptible check, JL 24 under greenhouse conditions. Activities of oxidative enzymes and the amounts of secondary metabolites and proteins were quantified at 6 days after JA and SA application/insect infestation. Data was also recorded on plant damage and H. armigera larval weights and survival. Results Higher levels of enzymatic activities and the amounts of secondary metabolites were observed in the insect-resistant genotypes pretreated with JA and then infested with H. armigera than in JL 24. The insect-resistant genotypes suffered lower insect damage and resulted in poor survival and lower weights of H. armigera larvae than JL 24.In some cases, both JA and SA showed similar effect. Conclusion JA and SA induced the activity of antioxidative enzymes in groundnut plants against H. armigera, and reduced its growth and development. However, induced response to application of JA was greater than SA, and resulted in reduced plant damage, larval weights and survival, suggesting that induced resistance can be used as a component of pest management in groundnut

    Defensive Responses in Groundnut Against Chewing and Sap-Sucking Insects

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    Induced resistance is one of the important components of host plant resistance to insects. We studied the induced defensive responses in groundnut genotypes with different levels of resistance to the leaf defoliator Helicoverpa armigera and the sap-sucking insect Aphis craccivora to gain an understanding of the induced resistance to insects and its implications for pest management. The activity of the defensive enzymes (peroxidase, polyphenol oxidase, phenylalanine ammonia lyase, superoxide dismutase, ascorbate peroxidase, and catalase) and the amounts of total phenols, hydrogen peroxide, malondialdehyde, and proteins were recorded at 6 days after infestation. Induction of enzyme activities and the amounts of secondary metabolites were greater in the insect-resistant genotypes ICGV 86699, ICGV 86031, ICG 2271, and ICG 1697 infested with H. armigera and A. craccivora than in the susceptible check JL 24. The resistant genotypes suffered lower insect damage and resulted in lower Helicoverpa larval survival and weights than those larvae fed on the susceptible check JL 24. The number of aphids was significantly lower on insect-resistant genotypes than on the susceptible check JL 24. The results suggested that groundnut plants respond to infestation by H. armigera and A. craccivora in a similar way; however, the degree of the response differed across the genotypes and insects, and this defense response is attributed to various defensive enzymes and secondary metabolites

    Football: a counterpoint to the procession of pain on the Western Front, 1914-1918?

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    In this article, three artworks of the First World War containing images of recreational football are analysed. These three images, In the Wings of the Theatre of War, Artillery Men at Football and Gassed, span the war from its beginning to its conclusion and are discussed in relationship to the development of recreational football in the front-line area, the evolving policies of censorship and propaganda and in consideration of the national mood in Britain. The paper shows how football went from being a spontaneous and improvised pastime in the early stages of the war to a well organized entertainment by warā€™s end. The images demonstrate how the war was portrayed as a temporary affair by a confident nation in 1914 to a more resigned acceptance of a semi-permanent event to be endured by 1918; however, all three artworks show that the sporting spirit, and hence the fighting spirit, of the British soldier was intact

    Climate change effects on pest spectrum and incidence in grain legumes

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    Global warming and climate change will influence activity, diversity, distribution and population dynamics of insect pests including the grain legumes. Several insect pests damage grain legume crops, of which the pod borer, Helicoverpa armigera; spotted pod borer, Maruca vitrata; spiny pod borer, Etiella zinckenella; pod fly, Melanagromyza obtusa; aphid, Aphis craccivora; defoliators, Spodoptera litura and S. exigua; thrips, Megaleurothrips usitatus and Caliothrips indicus and the bruchid, Callasobruchus chinensis cause extensive losses in grain legumes. The incidence and extent of losses due to these pests varies across seasons, locations, and cropping systems.Ā The pest spectrum on grain legumes will change considerably due to impending global warming and climate change. The geographical distribution of some of the pests might extend to temperate regions in Europe and America, while the outbreaks of some other pests will become more frequent. Several outbreaks of pod borer, H. armigera and spotted pod borer, M. vitrata have been recorded on grain legumes in India, which at times have resulted in complete crop loss. The scale insect, Ceroplastodes cajani in pigeonpea and beet armyworm, Spodoptera exigua, mealy bug, Ferrisia virgata, and white fly, Bemisia tabaci in chickpea have emerged as new pests; while leaf miner, Porphyrosela neodoxa, mealy bugs, Drepanococcus cajani, and Coccidohystrix insolita are some of the emerging pest problems in pigeonpea in India. In addition, there will be greater genotype x environment interactions for expression of resistance to insect pests, and this warrants a greater effort for identification of diverse sources of resistance and need for integrated pest management packages that will be effective under global warming and climate change

    Political Regimes and Sovereign Credit Risk in Europe, 1750-1913

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    This article uses a new panel data set to perform a statistical analysis of political regimes and sovereign credit risk in Europe from 1750 to 1913. Old Regime polities typically suffered from fiscal fragmentation and absolutist rule. By the start of World War I, however, many such countries had centralized institutions and limited government. Panel regressions indicate that centralized and?or limited regimes were associated with significant improvements in credit risk relative to fragmented and absolutist ones. Structural break tests also reveal close relationships between major turning points in yield series and political transformations

    Mechanism of Resistance in Mungbean [Vigna radiata (L.) R. Wilczek var. radiata] to bruchids, Callosobruchus spp. (Coleoptera: Bruchidae)

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    Mungbean [Vigna radiata (L.) R. Wilczek var. radiata] is an important pulse crop in Asia, and is consumed as dry seeds and as bean sprouts. It is an excellent source of digestible protein. Bruchids [Callosobruchus chinensis (L.) and Callosobruchus maculatus (F.)] are the important pests of mungbean and cause damage in the field and in storage. Bruchid infestation reduces the nutritional and market value of the grain and renders seeds unfit for human consumption, agricultural and commercial uses. These pests are controlled mainly by fumigation with highly toxic chemicals such as carbon disulfide, phosphene, and methyl bromide, or by dusting with several other insecticides, which leave residues on the grain, thus, threatening food safety. Some plant-based extracts have been found useful in controlling bruchids, but are not fully successful due to their short-term activity, rapid degradability, and potentially negative effect on seed germination. Although some wild sources of bruchid resistance in mungbean have been reported, which have been used to develop bruchid- resistant lines, undesirable genetic linkages threaten the proper exploitation of genetic diversity from wild germplasm into commercial cultivars. Further, biotype variation in bruchids has rendered some mungbean lines susceptible that otherwise would have been resistant to the pest. Host plant resistance is a cost-effective and a safe alternative to control bruchids in mungbean and is associated with morphological, biochemical, and molecular traits. These traits affect insect growth and development, thereby, reduce the yield losses by the pests. Understanding the defense mechanisms against insect pests could be utilized in exploiting these traits in crop breeding. This review discusses different traits in mungbean involved in defense against bruchids and their utility in pest management. We also highlight the breeding constraints for developing bruchid-resistant mungbean and how can these constraints be minimized. We further highlight the importance of supporting conventional breeding techniques by molecular techniques such as molecular markers linked to bruchid resistance

    Surgical interventions for the management of chronic groin pain after hernia repair (postherniorrhaphy inguinodynia) in adults

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    This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To assess the efficacy and safety of surgical interventions for the management of groin pain as a consequence of previous inguinal hernia repair in adults
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