scholarly journals Environmental variables influence the developmental stages of the citrus leafminer, infestation level and mined leaves physiological response of Kinnow mandarin

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rab Nawaz ◽  
Nadeem Akhtar Abbasi ◽  
Ishfaq Ahmad Hafiz ◽  
Muhammad Faisal Khan ◽  
Azeem Khalid
Keyword(s):  
Climate Change ◽  
Physiological Response ◽  
Developmental Stages ◽  
Leaf Growth ◽  
Citrus Fruit ◽  
Leaf Size ◽  
Economic Loss ◽  
Tree Age ◽  
Ecological Zones ◽  
Citrus Leafminer

AbstractClimate change has not only exacerbated abiotic stress, but has also rendered external conditions more feasible for pests to spread and infest citrus fruit. Citrus leafminer (Phyllocnistis citrella) is a potential pest that directly feeds the newly sprouted leaves and twigs of all three spring, summer and autumn flushes. Increasing temperatures in spring and autumn, leafminer accrued more heat units or developmental degree days to accelerate the biological stages of its life-cycle, thereby increasing the pressure of infestation. Present work was conducted at three different environmental conditions in Sargodha, Toba Tek Singh (TTS) and Vehari districts of the Punjab province, Pakistan; all three experimental sites were located in different agro-ecological zones. More infestation was recorded in all three flushes at TTS and Vehari than in Sargodha. Overall, more damage was observed due to higher temperatures in TTS and Vehari than in Sargodha. After May–June heat stress, spontaneous vegetative growth continued from July to November, produced newly spouted tender leaves for feeding the leafminer larvae, and was seen more in TTS and Vehari. Leafminer larva prefers to enter young and tender leaves with a maximum entrance in leaves up to 1 cm2 in size while observing no entrance above 3 cm2 of leaf size. Physiological response of leaves primarily attributed to chlorophyll and carotenoid contents, both of which were recorded lower in the mined leaves, thereby reducing leaf photosynthetic activity. Similarly, lower levels of polyphenols and antioxidant activity were also recorded in the mined leaves. The on-tree age of mined leaves of three vegetative flushes of Kinnow plant was also less counted than non-mined leaves. Climate change has affected vegetative phenology and become feasible for pests due to extemporaneous leaf growth, particularly leafminer, and eventually causes economic loss by supplying low carbohydrates either to hanging fruits or next-season crops.

scholarly journals Ticks of the genus Rhipicephalus Koch, 1844 in Senegal: Review host associations, chorology, and associated human and animal pathogens

2021 ◽  
Vol 74 (1) ◽  
pp. 61-69
Author(s):  
Massamba Sylla ◽  
Marc Souris ◽  
Jean-Paul Gonzalez
Keyword(s):  
Climate Change ◽  
Developmental Stages ◽  
Complex Data ◽  
Medical Entomology ◽  
Ecological Zones ◽  
Animal Pathogens ◽  
Tick Distribution ◽  
Vertebrate Hosts ◽  
Host Relationships

Ticks of the genus Rhipicephalus (Acari: Ixodidae) in Senegal were reviewed. The data presented originate from a tick collection maintained at IRD’s Laboratory of Medical Entomology since 1967 and continuously enriched with samples obtained from different vertebrate hosts captured during various projects conducted in Senegal from 1987 to 2007. Fifteen Rhipicephalus tick species were collected and characterized, resulting in 1127 referenced collections. Three species were of the Boophilus subgenus: Rhipicephalus (Bo.) annulatus, Rh. (Bo.) decoloratus and Rh. (Bo.) geigyi. The twelve others were Rh. boueti, Rh. cuspidatus, Rh. evertsi, Rh. guilhoni, Rh. lunulatus, Rh. muhsamae, Rh. sanguineus, Rh. senegalensis, Rh. sulcatus, Rh. tricuspis, Rh. turanicus and Rh. ziemanni. Although there were recent indications that Rh. turanicus should have been considered as part of the Rh. sanguineus s.l. complex, data regarding these two ticks were presented separately. The collection comprised 14,165 tick specimens at different developmental stages. Data concerning their host relationships as well as distribution and seasonal dynamics were also presented. Vertebrate hosts were identified and listed in the different ecological zones of Senegal. The role of the ticks as potential vectors of pathogens has been reviewed. Climate change, causing variations in rainfall and temperature, will impact tick distribution and dynamics. The situation supports the necessity of this inventory of tick populations for (re)emerging tick-borne diseases surveillance and monitoring.

scholarly journals Transcriptome Analysis of Ginkgo biloba L. Leaves across Late Developmental Stages Based on RNA-Seq and Co-Expression Network

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 315
Author(s):  
Hailin Liu ◽  
Xin Han ◽  
Jue Ruan ◽  
Lian Xu ◽  
Bing He
Keyword(s):  
Ginkgo Biloba ◽  
Leaf Development ◽  
Developmental Stages ◽  
Leaf Growth ◽  
Rna Seq ◽  
Final Size ◽  
Dioecious Species ◽  
Related Factors ◽  
New Genes ◽  
Gene Modules

The final size of plant leaves is strictly controlled by environmental and genetic factors, which coordinate cell expansion and cell cycle activity in space and time; however, the regulatory mechanisms of leaf growth are still poorly understood. Ginkgo biloba is a dioecious species native to China with medicinally and phylogenetically important characteristics, and its fan-shaped leaves are unique in gymnosperms, while the mechanism of G. biloba leaf development remains unclear. In this study we studied the transcriptome of G. biloba leaves at three developmental stages using high-throughput RNA-seq technology. Approximately 4167 differentially expressed genes (DEGs) were obtained, and a total of 12,137 genes were structure optimized together with 732 new genes identified. More than 50 growth-related factors and gene modules were identified based on DEG and Weighted Gene Co-expression Network Analysis. These results could remarkably expand the existing transcriptome resources of G. biloba, and provide references for subsequent analysis of ginkgo leaf development.

scholarly journals Identification of Lasiodiplodia pseudotheobromae Causing Fruit Rot of Citrus in China

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 202
Author(s):  
Jianghua Chen ◽  
Zihang Zhu ◽  
Yanping Fu ◽  
Jiasen Cheng ◽  
Jiatao Xie ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Elongation Factor ◽  
Morphological Characteristics ◽  
Citrus Fruit ◽  
Economic Loss ◽  
Fruit Rot ◽  
Post Inoculation ◽  
Citrus Reticulata ◽  
Postharvest Diseases ◽  
Citrus Reticulata Blanco

Considering the huge economic loss caused by postharvest diseases, the identification and prevention of citrus postharvest diseases is vital to the citrus industry. In 2018, 16 decayed citrus fruit from four citrus varieties—Satsuma mandarin (Citrus unshiu), Ponkan (Citrus reticulata Blanco cv. Ponkan), Nanfeng mandarin (Citrus reticulata cv. nanfengmiju), and Sugar orange (Citrus reticulata Blanco)—showing soft rot and sogginess on their surfaces and covered with white mycelia were collected from storage rooms in seven provinces. The pathogens were isolated and the pathogenicity of the isolates was tested. The fungal strains were identified as Lasiodiplodia pseudotheobromae based on their morphological characteristics and phylogenetic analyses using the internal transcribed spacer regions (ITS), translation elongation factor 1-α gene (TEF), and beta-tubulin (TUB) gene sequences. The strains could infect wounded citrus fruit and cause decay within two days post inoculation, but could not infect unwounded fruit. To our knowledge, this is the first report of citrus fruit decay caused by L. pseudotheobromae in China.

Collective Risk and Distributional Equity in Climate Change Bargaining

2021 ◽  
pp. 002200272110273
Author(s):  
Aseem Mahajan ◽  
Reuben Kline ◽  
Dustin Tingley
Keyword(s):  
Climate Change ◽  
Characteristic Feature ◽  
Economic Loss ◽  
Bargaining Model ◽  
Intergovernmental Panel ◽  
Climate Negotiations ◽  
Collective Risk ◽  
International Climate ◽  
Alternating Offers ◽  
International Climate Negotiations

International climate negotiations occur against the backdrop of increasing collective risk: the likelihood of catastrophic economic loss due to climate change will continue to increase unless and until global mitigation efforts are sufficient to prevent it. We introduce a novel alternating-offers bargaining model that incorporates this characteristic feature of climate change. We test the model using an incentivized experiment. We manipulate two important distributional equity principles: capacity to pay for mitigation of climate change and vulnerability to its potentially catastrophic effects. Our results show that less vulnerable parties do not exploit the greater vulnerability of their bargaining partners. They are, rather, more generous. Conversely, parties with greater capacity are less generous in their offers. Both collective risk itself and its importance in light of the recent Intergovernmental Panel on Climate Change report make it all the more urgent to better understand this crucial strategic feature of climate change bargaining.

Climate change refugia: landscape, stand and tree-scale microclimates in epiphyte community composition

2021 ◽  
Vol 53 (1) ◽  
pp. 135-148
Author(s):  
Christopher J. Ellis ◽  
Sally Eaton
Keyword(s):  
Climate Change ◽  
Community Composition ◽  
Large Scale ◽  
Biological Response ◽  
Tree Age ◽  
Local Effects ◽  
Vulnerability To Climate Change ◽  
Or Gene ◽  
Water Holding ◽  
Epiphyte Community

AbstractThere is growing evidence that species and communities are responding to, and will continue to be affected by, climate change. For species at risk, vulnerability can be reduced by ensuring that their habitat is extensive, connected and provides opportunities for dispersal and/or gene flow, facilitating a biological response through migration or adaptation. For woodland epiphytes, vulnerability might also be reduced by ensuring sufficient habitat heterogeneity, so that microhabitats provide suitable local microclimates, even as the larger scale climate continues to change (i.e. microrefugia). This study used fuzzy set ordination to compare bryophyte and lichen epiphyte community composition to a large-scale gradient from an oceanic to a relatively more continental macroclimate. The residuals from this relationship identified microhabitats in which species composition reflected a climate that was more oceanic or more continental than would be expected given the prevailing macroclimate. Comparing these residuals to features that operate at different scales to create the microclimate (landscape, stand and tree-scale), it was possible to identify how one might engineer microrefugia into existing or new woodland, in order to reduce epiphyte vulnerability to climate change. Multimodel inference was used to identify the most important features for consideration, which included local effects such as height on the bole, angle of bole lean and bark water holding capacity, as well as tree species and tree age, and within the landscape, topographic wetness and physical exposure.

Analysis of smallholder farmers’ vulnerability to climate change and variability in south Wollo, north east highlands of Ethiopia: An agro-ecological system-based approach

2021 ◽  
Author(s):  
Yimer Mohammed ◽  
Kindie Tesfaye ◽  
Menfese Tadesse ◽  
Fantaw Yimer
Keyword(s):  
Climate Change ◽  
Adaptive Capacity ◽  
Smallholder Farmers ◽  
Contributing Factors ◽  
Scale Level ◽  
Ecological Zones ◽  
Micro Scale ◽  
Climate Change And Variability ◽  
North East ◽  
Agro Ecological Zones

Abstract Background: Climate change and variability has been significantly affecting the Ethiopian agricultural production and thereby smallholder farmers livelihoods. The level of vulnerability varied across agro-ecological zones (AEZs). Identification of difference in the level of vulnerability of a system is important in selecting appropriate and effective adaption options to climate change. Therefore, the aim of this study was to analyze the level of vulnerability of agricultural communities to climate change and variability at micro-scale level in five agro-ecological zones (AEZs) of south Wollo, north east highlands of Ethiopia. Data was collected from a representative of 502 sample households from five AEZs through multi stage random sampling methods. Focus group discussion and key informant interviews were also carried out to supplement and substantiate the quantitative data. The indicator based approach was used to empirically calculate vulnerability. Principal Component Analysis (PCA) was applied to give weight for indicators and generate index of vulnerability contributing factors. Results: The results showed that each of the vulnerability contributing factors (exposure, sensitivity and adaptive capacity) varied across the AEZs. M3, SM2 and SM3 are the most exposed AEZs but having a relatively better adaptive capacity whereas M1, M2 and M3 are the most sensitive AEZs with relatively low adaptive capacity to climate variability and change. Overall, SM2 is the most vulnerable AEZ which exhibited high sensitivity and low adaptive capacity followed by M1. Conclusions: The study explored sources and levels of vulnerability to each agro-ecology. Since the study is conducted at micro-scale level, it helps decision makers and development partners to have context-specific understanding of the impact of climate change and variability and design appropriate adaptation measures to address the specific situations.

scholarly journals Will Climate Change Exacerbate the Economic Damage of Flood to Agricultural Production? A Case Study of Rice in Ha Tinh Province, Vietnam

2021 ◽  
Vol 9 ◽  
Author(s):  
Pham Quy Giang ◽  
Tran Trung Vy
Keyword(s):  
Climate Change ◽  
Extreme Precipitation ◽  
Agricultural Production ◽  
Climate Change Impacts ◽  
Economic Loss ◽  
Baseline Period ◽  
Rice Production ◽  
Generalized Extreme Value Distribution ◽  
Economic Damage

In developing countries in general and in Vietnam in particular, flood induced economic loss of agriculture is a serious concern since the livelihood of large populations depends on agricultural production. The objective of this study was to examine if climate change would exacerbate flood damage to agricultural production with a case study of rice production in Huong Son District of Ha Tinh Province, North-central Vietnam. The study applied a modeling approach for the prediction. Extreme precipitation and its return periods were calculated by the Generalized Extreme Value distribution method using historical daily observations and output of the MRI-CGCM3 climate model. The projected extreme precipitation data was then employed as an input of the Mike Flood model for flood modeling. Finally, an integrated approach employing flood depth and duration and crop calendar was used for the prediction of potential economic loss of rice production. Results of the study show that in comparison with the baseline period, an increase of 49.14% in the intensity of extreme precipitation was expected, while the frequency would increase 5 times by 2050s. As a result, the seriousness of floods would increase under climate change impacts as they would become more intensified, deeper and longer, and consequently the economic loss of rice production would increase significantly. While the level of peak flow was projected to rise nearly 1 m, leading the area of rice inundated to increase by 12.61%, the value of damage would rise by over 21% by 2050s compared to the baseline period. The findings of the present study are useful for long-term agricultural and infrastructural planning in order to tackle potential flooding threats to agricultural production under climate change impacts.

scholarly journals Drought-tolerant Varieties as an Adaptation Strategy in the Context of Climate Change: Insight from Maize Production Systems in Benin

2020 ◽  
pp. 1-7
Author(s):  
Mohamed Nasser Baco
Keyword(s):  
Climate Change ◽  
Food Security ◽  
Crop Production ◽  
Production Systems ◽  
Smallholder Farmers ◽  
Value Chains ◽  
Maize Production ◽  
Ecological Zones ◽  
Drought Tolerant ◽  
Agro Ecological Zones

Previous studies suggested that maize is set to become a cash crop while ensuring food security better than any other crop. However, climate change has become one of the key production constraints that are now hampering and threatening the sustainability of maize production systems. We conducted a study to better understand changes here defined as adaptations made by smallholder farmers to ensure food security and improve income through maize production in a climate change context. Our results show that maize farmers in northern Benin mainly rely on traditional seeds. Drought as abiotic stress is perceived by farmers in many agro-ecological zones as a disruptive factor for crop production, including maize. When drought is associated with pest damages, both the quantity (i.e. yield) and the quality (i.e. attributes) of products/harvests are negatively affected. The adverse effects of drought continue to reduce production in different agro-ecological zones of the country, because of the lack of widespread adoption of tolerant varieties. The study suggests actions towards the production of drought-tolerant maize seeds, a promotion of seed companies, the organization of actors and value chains. Apart from climate change, the promotion of value chains is also emerging as one of the important aspects to take into account to sustain maize production in Benin.

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