Nitric oxide is an upstream signal involved in the multisignalling network during the Russian wheat aphid resistance response and its application enhances resistance

The Russian wheat aphid (RWA) is serious pest of wheat in South Africa since its discovery in 1978. Nitric oxide (NO) plays an essential role in the RWA resistance response of wheat. This study was conducted to establish whether NO acts upstream or downstream of salicylic acid (SA) during the RWA defence response and also to investigate the effect of NO application on RWA control. In addition, the involvement of peroxynitrite in the RWA resistance response of wheat was studied. Resistant and/or susceptible plants grown under controlled conditions (25 ± 2°C) were used. Using a NO donor, sodium nitroprusside (SNP), and a NO production inhibitor, sodium tungstate (NaWO4), it was proved that NO acts upstream of SA during the RWA resistance response of wheat. Furthermore, a significant decrease in RWA intrinsic increase rate (rm) and disease symptom development after SNP application emphasized the role of NO in the RWA resistance responses. High levels of peroxynitrite (by-product of NO) content in the RWA infested resistant plants and inhibition of secondary defence enzymes (β-1,3-glucanase and peroxidase) after urate (inhibitor of peroxynitrite production) application proposed the involvement of this molecule in the signalling events of the RWA resistance

Impacts of COVID-19 on Diverse Farm Systems in Tanzania and South Africa

Emerging information on the interactions between the COVID-19 pandemic and global food systems have highlighted how the pandemic is accentuating food crises across Africa. Less clear, however, are how the impacts differ between farming systems. Drawing on 50 key informant interviews with farmers, village leaders and extension officers in South Africa and Tanzania, we identify the effects of COVID-19 and associated measures to curb the spread of the disease on farming production systems, the coping mechanisms adopted by farmers, and explore their longer-term plans for adaptation. We focus on a diverse range of production systems, from small-scale mixed farming systems in Tanzania to large-scale corporate farms in South Africa. Our findings highlight how COVID-19 restrictions have interrupted the supply chains of agricultural inputs and commodities, increasing the storage time for produce, decreasing income and purchasing power, and reducing labour availability. Farmers’ responses were heterogeneous, with highly diverse small-scale farming systems and those less engaged with international markets least affected by the associated COVID-19 measures. Large-scale farmers were most able to access capital to buffer short-term impacts, whereas smaller-scale farms shared labour, diversified to subsistence produce and sold assets. However, compounded shocks, such as recent extreme climate events, limited the available coping options, particularly for smaller-scale and emerging farmers. The study highlights the need to understand the characteristics of farm systems to better equip and support farmers, particularly in contexts of uncertainty. We propose that policy actions should focus on (i) providing temporary relief and social support and protection to financially vulnerable stakeholders, (ii) job assurance for farmworkers and engaging an alternative workforce in farming, (iii) investing in farming infrastructure, such as storage facilities, digital communication tools and extension services, and (iv) supporting diversified agroecological farming systems

The distribution of Russian Wheat Aphid, Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae) in Turkey

The Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae), is one of the most economically important and widely distributed pests of wheat in the world. In 1962, D. noxia caused crop losses between 25 and 60% in the central province of Konya, Turkey. In this study, the current status of the pest in wheat-producing areas of Turkey was investigated along a route from Izmir to Manisa, Usak, Kutahya, Eskisehir, Aksehir, Ankara, Konya, Aksaray, Nevsehir, Yozgat and Erzurum. D. noxia was detected in 58 of the 100 wheat fields surveyed in most fields and wheat was at the heading stage. The population density of the pest was low in 23 fields, medium in 22 fields and high in 13 fields. The percentage of infestation was low in 31 fields, medium in 12 fields, and high in three fields and very high in three fields. D. noxia was collected from bread or durum wheat plants (71%), barley plants (10%), volunteer oats (8%) (Avena fatua), volunteer wheat (6%), false barley (Hordeum murinum) (4%) and natural grasses (1%). According to results of the study, population density, damage and infestation rates of D. noxia were higher in high altitudes

Radical land reform in South Africa - a comparative perspective?

A great deal of political rhetoric has been uttered regarding radical economic transformation that includes calls for more radical land reform proposals. This rhetoric is the source of political mobilisation in both the governing African National Congress (ANC), as well as the Economic Freedom Fighters (EFF) opposition. While the ANC call for the end of the willing buyer, willing seller principle in land reform policies and legislation in line with their National Democratic Revolution (NDR), the EFF support a more extreme expropriation without compensation approach. Both these approaches can be regarded as forms of radical land reform that are grounded in their specific ideological orientations. Since no academic definition exists regarding the concept “radical land reform”, it is necessary that this is conceptualised. In order to analyse the possible implications of radical land reform, this article explores the outcomes of similar approaches in the People’s Republic of China (PRC), the former Union of Soviet Socialist Republics (USSR) and Zimbabwe. The lessons of this comparative analysis indicate that land reform requires a balance between existing land rights and food security on the one hand, and the urgency for historical redress and redistribution on the other

Dung beetle assemblage structure across the aridity and trophic resource gradient of the Botswana Kalahari: patterns and drivers at regional and local scales

Understanding pattern and process at both regional and local scales is important for conservation planning although such knowledge of insects is frequently lacking. To assess patterns along a regional gradient of increasing aridity and diminishing food resources in the Botswana Kalahari, Scarabaeine dung beetles were sampled quantitatively using four dung types at three local sites in six regional areas. At regional scale, factor analysis of species abundance extracted a maximum of six factors, each dominated by a single area. Therefore, the statistical significance of regional spatial variation far outweighed that of dung type association. At local scale, six factor analyses of species abundance extracted from four to six factors. The importance of local dung type associations was relatively high but diminished with increasing local spatial heterogeneity. At regional scale, hierarchical analysis of oblique factors divided assemblages into unique local and shared regional components. Primary extended factors accounted for 40–50 % of unique local faunal composition in five out of six areas. Two secondary extended factors showed either high shared proportional contribution to regional assemblage structure in the northeast with a steep decline to the southwest, or an opposite trend. Their point of intersection was consistent with a boundary zone between mesic northeast and arid southwest faunal components in the central Kalahari. Despite some inconsistencies in rank position between regression methods, rainfall, temperature, and mammal density/diversity were the strongest influences on regional patterns defined by secondary factors. Patterns are discussed according to conservation and changes in land usage around reserves.The GEF-Small Grant Programme and the University of Pretoriahttp://www.springerlink.com/content/100177/hb2013ab201