scholarly journals Impacts of enhanced fertilizer applications on tropospheric ozone and crop damage over sub-Saharan Africa

2018 ◽  
Vol 180 ◽  
pp. 117-125 ◽  
Author(s):  
Yaoxian Huang ◽  
Jonathan E. Hickman ◽  
Shiliang Wu
Author(s):  
Matthew W. Jordon ◽  
Talya D. Hackett ◽  
Fred Aboagye-Antwi ◽  
Vincent Y. Eziah ◽  
Owen T. Lewis

Abstract Insect crop pests are a major threat to food security in sub-Saharan Africa. Configuration of semi-natural habitat within agricultural landscapes has the potential to enhance biological pest control, helping to maintain yields whilst minimising the negative effects of pesticide use. Fall armyworm (Spodoptera frugiperda, J. E. Smith) is an increasingly important pest of maize in sub-Saharan Africa, with reports of yield loss between 12 and 45%. We investigated the patterns of fall armyworm leaf damage in maize crops in Ghana, and used pitfall traps and dummy caterpillars to assess the spatial distribution of potential fall armyworm predators. Crop damage from fall armyworm at our study sites increased significantly with distance from the field edge, by up to 4% per m. We found evidence that Araneae activity, richness and diversity correspondingly decreased with distance from semi-natural habitat, although Hymenoptera richness and diversity increased. Our preliminary findings suggest that modifying field configuration to increase the proximity of maize to semi-natural habitat may reduce fall armyworm damage and increase natural enemy activity within crops. Further research is required to determine the level of fall armyworm suppression achievable through natural enemies, and how effectively this could safeguard yields.


Nematology ◽  
2021 ◽  
pp. 1-39
Author(s):  
Raymond Lesley Collett ◽  
Mariette Marais ◽  
Mieke Daneel ◽  
Milad Rashidifard ◽  
Hendrika Fourie

Summary Crop damage inflicted by Meloidogyne enterolobii justifies an updated literature review focusing on recent discoveries about its identification, biology and management. Since its description in 1983, M. enterolobii has become a pest of great concern, particularly due to its virulence, which renders controlling this nematode pest a challenge. The global distribution of M. enteroblii is summarised, with emphasis placed on limited research done for the species in sub-Saharan Africa where food production and security is threatened by root-knot nematode parasitism. Novel advances in methods used to detect M. enterolobii are touched upon, especially the improvement in advanced molecular techniques that complements shortcomings in morphology and morphometic approaches. Despite these exciting developments, the employment of effective management strategies to combat the species remains problematic. Future research on various aspects of M. enterolobii is crucial, with focus to be placed on the use of available resources to contain damage caused by this species.


2020 ◽  
Vol 20 (95) ◽  
Author(s):  
Alun Thomas

Recent micro level data from East Africa is used to benchmark aggregate data and assess the role of agricultural inputs in explaining variation in crop yields on smallholding plots. Fertilizer, improved seeds, protection against erosion and pesticides improve crop yields in Rwanda and Ethiopia, but not Uganda, possibly associated with lack of use there. With all positive yield determinants in place, wheat and maize yields could increase fourfold. The data hints at the negative effect of climate change on yields and the benefits of accompanying measures to mitigate its adverse impact (access to finance and protection against erosion). The adverse effect of crop damage on yields varies between 12/13 percent (Rwanda, Uganda) to 36 percent (Ethiopia). Protection against erosion and investment financing mitigate these effects considerably.


2017 ◽  
Vol 1 (6) ◽  
pp. 533-537
Author(s):  
Lorenz von Seidlein ◽  
Borimas Hanboonkunupakarn ◽  
Podjanee Jittmala ◽  
Sasithon Pukrittayakamee

RTS,S/AS01 is the most advanced vaccine to prevent malaria. It is safe and moderately effective. A large pivotal phase III trial in over 15 000 young children in sub-Saharan Africa completed in 2014 showed that the vaccine could protect around one-third of children (aged 5–17 months) and one-fourth of infants (aged 6–12 weeks) from uncomplicated falciparum malaria. The European Medicines Agency approved licensing and programmatic roll-out of the RTSS vaccine in malaria endemic countries in sub-Saharan Africa. WHO is planning further studies in a large Malaria Vaccine Implementation Programme, in more than 400 000 young African children. With the changing malaria epidemiology in Africa resulting in older children at risk, alternative modes of employment are under evaluation, for example the use of RTS,S/AS01 in older children as part of seasonal malaria prophylaxis. Another strategy is combining mass drug administrations with mass vaccine campaigns for all age groups in regional malaria elimination campaigns. A phase II trial is ongoing to evaluate the safety and immunogenicity of the RTSS in combination with antimalarial drugs in Thailand. Such novel approaches aim to extract the maximum benefit from the well-documented, short-lasting protective efficacy of RTS,S/AS01.


1993 ◽  
Vol 47 (3) ◽  
pp. 555-556
Author(s):  
Lado Ruzicka

Crisis ◽  
2011 ◽  
Vol 32 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Eugene Kinyanda ◽  
Ruth Kizza ◽  
Jonathan Levin ◽  
Sheila Ndyanabangi ◽  
Catherine Abbo

Background: Suicidal behavior in adolescence is a public health concern and has serious consequences for adolescents and their families. There is, however, a paucity of data on this subject from sub-Saharan Africa, hence the need for this study. Aims: A cross-sectional multistage survey to investigate adolescent suicidality among other things was undertaken in rural northeastern Uganda. Methods: A structured protocol administered by trained psychiatric nurses collected information on sociodemographics, mental disorders (DSM-IV criteria), and psychological and psychosocial risk factors for children aged 3–19 years (N = 1492). For the purposes of this paper, an analysis of a subsample of adolescents (aged 10–19 years; n = 897) was undertaken. Results: Lifetime suicidality in this study was 6.1% (95% CI, 4.6%–7.9%). Conclusions: Factors significantly associated with suicidality included mental disorder, the ecological factor district of residence, factors suggestive of low socioeconomic status, and disadvantaged childhood experiences.


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