Toxicological study of plant extracts on termite and laboratory animals

Toxic activity of leaf extracts of Polygonum hydropiper L. and Pogostemon parviflorus Benth. were tested in the laboratory against tea termite, Odontotermes assamensis Holm. Both the tested extracts caused mortality of the termite. The highest toxic activity (100%) was found in the 2.0% chloroform extracts of P. hydropiper. The chloroform extract of P. hydropiper was explored for possible mammalian toxicological effects. The LD50 was 758.58 mg/kg in male albino mice. Subcutaneous injection of sub-lethal dose of extract into male mice once a week for 6 weeks failed to express any significant influence on WBC, RBC count and blood cholesterol.     

Mosquito biodiversity of Dibru-Saikhowa biosphere reserve in Assam, India

Entomological surveys were conducted for three consecutive years in core and buffer zone of the Dibru-Saikhowa biosphere reserve in pre monsoon, monsoon and post-monsoon seasons. A total of 52 species of mosquitoes under eleven genera have been detected. The genus Anopheles (18 species) was the predominant followed by Culex, Aedes, Mansonia, Armigeres, Mimomyia, Ochlerostatus, Malaya, Toxorhynchites, Ficalbia and Aedeomyia. The buffer zone of the forest reserve where human habitations are there exhibited the presence of maximum number of species (49 species under 10 genera) in comparison to core zone (42 species under 10 genera). In buffer zone, maximum numbers of species (38) were recorded in monsoon season followed by post- monsoon (35 species) and Pre-monsoon season (34 species). Whereas in core zone, maximum number of species were collected in post monsoon season followed by pre monsoon season and monsoon season. In Core and buffer zone, the maximum species were recorded from the ground pool habitat and slow flowing stream respectively. Among the disease vectors, the potential Japanese encephalitis vectors incriminated in India were very much prevalent. This study provides the list of available mosquito species recorded for the first time in the Dibru-Saikhowa biosphere reserve.     

Influencing resilience: the role of policy entrepreneurs in mainstreaming climate adaptation

One way to make development pathways more resilient in the face of a changing climate has been through mainstreaming adaptation into government policies, planning and sectoral decision‐making. To date, many of the transferable lessons have taken the form of technical approaches such as risk assessments and toolkits. This article instead draws on evidence from South Asia to emphasise some of the more tacit and informal approaches used to influence adaptation policy. Despite their apparent significance in policy processes, such tactics are often neither planned for nor well reported in resilience‐building projects and programme documents. Using evidence to populate a typology of influencing strategies, this article looks particularly at the role of policy entrepreneurs who navigate the political complexity of both formal and informal governance systems to promote successful adaptation mainstreaming. It concludes with recommendations for adaptation and resilience programming that can more effectively harness the breadth of influencing strategies.     

Nanoweapon: control of mosquito breeding using carbon-dot-silver nanohybrid as a biolarvicide

Health issues induced by mosquito illnesses highlight the need for effective control. Here, we developed an efficient carbon-dot-silver nanohybrid to control Anopheles stephensi and Culex quinquefasciatus mosquito species. The nanohybrid was synthesized using a thermal method without addition of any toxic-reducing agent. Monohybrids are found within the ranges of 2–6 nm for carbon-dot and 10–35 nm for silver nanoparticles with uniform distribution. The uniformly dispersed nanohybrid solutions show excellent larvicidal activity within the concentration range of 0.5–1.0 ppm. Morphological studies evidence the presence of strong bonds between nanohybrid and sulphur- or phosphorus-containing compounds such as proteins and DNA present in the larval body. This explains tissue damage at very low concentrations of nanohybrid. Therefore, this nanoweapon has high potential for field applications.     

Nanotechnology applications and intellectual property rights in agriculture

Nanotechnology research uses specific properties of materials at the nanoscale to develop improved materials, devices, systems and therapeutics. There is a risk of overlapping patent claims and lack of distinction between nano-based and traditional patents due to the interdisciplinary nature of nanotechnology. There is an increasing trend of granted patents. The World Intellectual Property Organization and World Health Organization, regulatory and policy bodies, are working to make a comprehensive property right regulation for nanotechnology products. The USA, the leader of nanotechnology products, has made guidelines to make patent search easier for nano-based products. The European Patent Office has also created a new classification for nano-based inventions. Here we review the status of intellectual property rights protection of nanomaterial, environmental implications and application of nanotechnology in agriculture.     

Methane emission characteristics and its relations with plant and soil parameters under irrigated rice ecosystem of northeast India

Methane flux from rice varieties grown under two identical soils of Assam were monitored. In the first experiment, variety Jaya and GRT was grown in sandy loam soil of Lower Brahmaputra Valley Zone of Assam and the second experiment was conducted with variety Jyotiprasad and Bishnuprasad in sandy to sandy loam soils of Upper Brahmaputra Valley Zones of Assam. Methane flux recorded from variety Jyotiprasad and GRT was higher compared to variety Bishnuprasad and Jaya. The seasonal integrated flux recorded was 10.76 g m⁻², 9.98 g m⁻², 9.74 g m⁻² and 11.31 g m⁻² for variety GRT, Jaya, Bishnuprasad and Jyotiprasad, respectively. All the varieties exhibited two methane peaks one at maximum tillering stage and other at panicle initiation stage of the crop. Crop growth parameters such as leaf number, number of tillers and leaf area index (LAI) showed strong positive relationship with total methane flux. In both the experiments it was calculated that CH₄ emission was substantially influenced by crop phenology and growth. This study emphasise the relationship of different growth parameters with methane emission.     

Alternate wet and dry irrigation technology as a sustainable water management and disease vector control tool

Rising population and demands for rice as a staple food have created severe stress on freshwater availability for paddy cultivation. The literature suggests that conventional irrigation techniques are inadequate to overcome the water constraints arising from drought and extreme weather conditions. In the past few decades, there is an upsurge of scientific exploration of agricultural techniques in reinventing traditional methods of irrigation. Recently, alternate wet and dry irrigation (AWDI) method has shown great promise regarding profitable rice cultivation with limited water supply. The AWDI method is a trending water management system, which inundates rice fields with intermittent wet conditions followed by a dry period. This not only ensures adequate water supply but increases crop yield and water productivity index (WPI). The AWDI also helps in reducing parasitic mosquito population in the rice fields by minimizing the field flooding period and curtailing a major part of their life cycles. This review proposes a novel approach of emphasizing AWDI method as an important agricultural tool for supplementing rice fields with limited freshwater, increasing crop yield, and monitoring parasitic mosquito populations. The major objective of this study is to report the state-of-the-art scenario of AWDI method, critically analyze the research gaps related to conventional methods of irrigation and appreciate the futuristic long-term benefits of AWDI method. Literature survey was performed using search engines like Scopus, PubMed, Google Scholar, Research Gate, Science Direct, and Google Scholar. Comprehensive appraisal of resources (both offline and online) and critical evaluation of AWDI technicalities revealed that the AWDI reduced water usage by 45%, enhanced crop yield and improved WPI in paddy fields in the Asian sub-continent. The AWDI also curtailed the propagation of lethal mosquito species (Cx. tritaenorhynchus, Cx. vishnui, and Cx pseudovishnui) in rice fields. Therefore, the current study endorses AWDI as a promising substitute of conventional irrigation and a novel approach towards fulfilling water constraints that may be practiced anywhere in the world.     

Characterization of ammonia remover Bacillus albus (ASSF01) in terms of biofilm-forming ability with application in aquaculture effluent treatment

Environmental Science and Pollution Research - Presence of higher concentration of ammonia (> 0.5 mg/L) as well as nitrite (> 0.2 mg/L) in aquaculture environment create difficulties...