scholarly journals Insect Herbivore Populations and Plant Damage Increase at Higher Elevations

Insects ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1129
Author(s):  
Sulav Paudel ◽  
Pragya Kandel ◽  
Dependra Bhatta ◽  
Vinod Pandit ◽  
Gary W. Felton ◽  
...  
Keyword(s):  
Climatic Factors ◽  
Insect Pest ◽  
Tomato Fruit ◽  
Elevational Gradient ◽  
Interactive Effects ◽  
Leaf Miner ◽  
Insect Herbivore ◽  
Elevation Gradients ◽  
Climate Change Effects ◽  
Plant Damage

Elevation gradients are used as a proxy to simulate climate change effects. A field study was conducted along an elevational gradient in Nepal to understand the effects of abiotic conditions on agriculturally important insect herbivore populations (tobacco caterpillar: Spodoptera litura, tomato fruit worm: Helicoverpa armigera, and South American leaf miner, Tuta absoluta) and herbivory damage on tomatoes. Elevation ranged from 100 m to 1400 m above sea level, representing different climatic zones where tomatoes are grown. Contrary to our hypothesis, natural herbivore populations and herbivory damage significantly increased at higher elevations. Individual insect species responses were variable. Populations of S. litura and T. absoluta increased at higher elevations, whereas the H. armigera population was highest at the mid-elevational range. Temperature variations with elevation also affected insect catch numbers and the level of plant damage from herbivory. In the context of climate warming, our results demonstrate that the interactive effects of elevation and climatic factors (e.g., temperature) will play an important role in determining the changes in insect pest populations and the extent of crop losses.

scholarly journals Scale-Dependent Effects of Growth Stage and Elevational Gradient on Rice Phyllosphere Bacterial and Fungal Microbial Patterns in the Terrace Field

2022 ◽  
Vol 12 ◽  
Author(s):  
Pei Wang ◽  
Jianping Dai ◽  
Luyun Luo ◽  
Yong Liu ◽  
Decai Jin ◽  
...  
Keyword(s):  
Plant Growth ◽  
Growth Stage ◽  
Elevational Gradient ◽  
Fungal Communities ◽  
Growth Stages ◽  
Strong Positive Correlation ◽  
Elevation Gradients ◽  
Positive Correlation ◽  
Α Diversity ◽  
Phyllosphere Bacteria

The variation of phyllosphere bacterial and fungal communities along elevation gradients may provide a potential link with temperature, which corresponds to an elevation over short geographic distances. At the same time, the plant growth stage is also an important factor affecting phyllosphere microorganisms. Understanding microbiological diversity over changes in elevation and among plant growth stages is important for developing crop growth ecological theories. Thus, we investigated variations in the composition of the rice phyllosphere bacterial and fungal communities at five sites along an elevation gradient from 580 to 980 m above sea level (asl) in the Ziquejie Mountain at the seedling, heading, and mature stages, using high-throughput Illumina sequencing methods. The results revealed that the dominant bacterial phyla were Proteobacteria, Actinobacteria, and Bacteroidetes, and the dominant fungal phyla were Ascomycota and Basidiomycota, which varied significantly at different elevation sites and growth stages. Elevation had a greater effect on the α diversity of phyllosphere bacteria than on that phyllosphere fungi. Meanwhile, the growth stage had a great effect on the α diversity of both phyllosphere bacteria and fungi. Our results also showed that the composition of bacterial and fungal communities varied significantly along elevation within the different growth stages, in terms of both changes in the relative abundance of species, and that the variations in bacterial and fungal composition were well correlated with variations in the average elevation. A total of 18 bacterial and 24 fungal genera were significantly correlated with elevational gradient, displaying large differences at the various growth stages. Soluble protein (SP) shared a strong positive correlation with bacterial and fungal communities (p < 0.05) and had a strong significant negative correlation with Serratia, Passalora, unclassified_Trichosphaeriales, and antioxidant enzymes (R > 0.5, p < 0.05), and significant positive correlation with the fungal genera Xylaria, Gibberella, and Penicillium (R > 0.5, p < 0.05). Therefore, it suggests that elevation and growth stage might alter both the diversity and abundance of phyllosphere bacterial and fungal populations.

scholarly journals Effect of the outbreak of horse-chestnut leaf miner (Cameraria ohridella Deschka & Dimić) on tree-ring width in common horse-chestnut (Aesculus hippocastanum L.)

2021 ◽  
Author(s):  
Anna Cedro ◽  
Grzegorz Nowak
Keyword(s):  
Growth Rate ◽  
Tree Ring ◽  
Insect Pest ◽  
Ring Width ◽  
Leaf Miner ◽  
Horse Chestnut ◽  
Climate Response ◽  
Tree Ring Width ◽  
Temperature And Precipitation ◽  
Chestnut Leaf

Abstract Common horse-chestnut is frequently infested by the insect pest horse-chestnut leaf miner [HCLM; Cameraria ohridella (Deschka & Dimić, 1986), Gracillariidae, Lepidoptera]. The larvae, feeding on leaf parenchyma, cause browning and dehydration of leaves, which may be shed as early as in summer. The major aims of this study were: (1) to assess the effect of infestation by HCLM on ring-width dynamics in common horse-chestnut; (2) to determine the date of invasion of the pest; and (3) to compare the growth-climate response in the period before and after the invasion of HCLM. In 2017 in north-western Poland, samples from 30 horse-chestnut trees for the dendrochronological analysis were taken with help of a Pressler increment borer. The ring-width chronology was developed using standard dendrochronological methods. Dendroclimatological analyses were made in 2 periods: before the determined date of HCLM invasion (till the year 1999) and after the invasion (in 20002016). In 2000, in spite of favourable weather conditions, a reduced growth rate was observed in 91% of the analysed trees. The period of strong reductions lasted till 2010. Before the invasion, radial growth rate was dependent on temperature and precipitation in May and June of the current year, whereas after the invasion, the growth-climate response was dependent on temperature and precipitation in the preceding year and the correlation was stronger. Surprisingly, in recent years (2011–2016), in spite of infestation by HCLM every year, the health condition of the analysed trees has improved and tree-ring width has increased.

scholarly journals Climate Change Effects on the Crop Yield and Its Variability in Telangana, India

2020 ◽  
Vol 8 (1) ◽  
pp. 119-148
Author(s):  
Raju Guntukula ◽  
Phanindra Goyari
Keyword(s):  
Production Function ◽  
Minimum Temperature ◽  
Agricultural Development ◽  
Climatic Factors ◽  
Estimation Procedure ◽  
Maximum Temperature ◽  
Climate Change Effects ◽  
Enhancing Factor ◽  
Risk Reducing ◽  
Positive Effect

This study has examined the effects of climatic factors on mean yields and yield variability of four primary crops (rice, cotton, jowar and groundnut) in Telangana state by applying the Just and Pope production function over a period of 1956–2015. Using the three-stage feasible generalised least squares estimation procedure, we have estimated the production function of four crops. The empirical results have revealed that the effects of changes in climatic factors vary among crops under study. Maximum temperature has a significant adverse effect on rice, cotton and groundnut yields. Minimum temperature has a substantial positive effect on rice, cotton and groundnut. Further, rainfall is adversely related to cotton and groundnut yields. Maximum temperature has appeared as a risk-reducing factor for all study crops while minimum temperature as a risk-enhancing factor for rice, cotton and jowar. Lastly, rainfall has been found as a risk-enhancing factor for rice and groundnut whereas it is a risk-reducing factor for jowar and cotton. Results from the study have important implications on how Telangana’s farming sector will adapt to climate variability and change for sustainable agricultural development. JEL Codes: C23, Q18, Q51, Q54

scholarly journals Niche conservatism drives the elevational diversity gradient in major groups of free-living soil unicellular eukaryotes

2020 ◽  
Author(s):  
Leonardo D. Fernández ◽  
Christophe V. W. Seppey ◽  
David Singer ◽  
Bertrand Fournier ◽  
Dylan Tatti ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Elevational Gradient ◽  
Testate Amoebae ◽  
Latitudinal Gradients ◽  
Niche Conservatism ◽  
Energy Effect ◽  
Elevation Gradients ◽  
Diversity Gradient ◽  
Phylogenetic Overdispersion ◽  
Multicellular Organisms

Abstract Ancestral adaptations to warm and humid climates drive the biogeographical and macroecological patterns of numerous multicellular organisms. Recent evidence suggests that this niche conservatism may also be shaping broad-scale diversity patterns of soil unicellular organisms, although empirical evidence is limited to Acidobacteria and testate amoebae. Herein, we tested the predictions of this hypothesis for five major soil protist groups (Bacillariophyta, Cercomonadida, Ciliophora, Euglyphida and Kinetoplastida), separately, as well as combined, along an elevational gradient in Switzerland. We found support for the predictions of this hypothesis in all protist groups, including decreasing diversity and increasing geographical ranges towards high and cold elevations (Rapoport effect); correlations between diversity and temperature (species-energy effect); and communities phylogenetically structured by competition (phylogenetic overdispersion) at warm-humid sites and habitat filtering (phylogenetic clustering) at cold-humid sites. Mid-domain null models confirmed that these findings were not the result of stochastic processes. Our results therefore suggest that soil protists exhibit evolutionary constraints to warm and humid climates, probably linked to an ancestral adaptation to (sub)tropical-like environments, which limits their survival in exceedingly cold sites. This niche conservatism possibly drives their biogeographical and macroecological patterns both at the local (e.g., temperature, humidity gradients along elevation gradients) and more global (e.g., latitudinal gradients) spatial scales.

scholarly journals Effect of Silicon fertilization on two major insect pests of tomato under greenhouse conditions

2021 ◽  
Author(s):  
Aqeel Alyousuf ◽  
Dawood Hamid ◽  
Mohsen A. Desher ◽  
Amin Nikpay ◽  
Henk-Marten Laane
Keyword(s):  
Population Density ◽  
Insect Pests ◽  
Insect Pest ◽  
Tomato Leaf ◽  
Leaf Miner ◽  
Pest Species ◽  
Tomato Crop ◽  
Soil Drench ◽  
Tomato Leaf Miner ◽  
Acid Formulation

Abstract Tomato (Solanum lycopersicum L) is an important vegetable crop in Iraq. This horticultural crop is attacked by several insect pest species. Among them, the whitefly Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) and the tomato leaf miner Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) are the major threat of greenhouse tomatoes in Basrah province in south Iraq. The management of these pests is heavily based on application of chemical pesticides. Vast application of pesticides caused harmful damage to the environment, human health and may increasing the risk of pest resistance on insect populations. One of the promising strategies which are compatible with organic farming is application of silicon for enhancing plant vigor and resistance to pest damage on various agricultural crops. Due to these facts, the experiments have been carried out at Basrah University to evaluate the effects of silicon (Si) fertilization on tomato plants for reducing damage of these two major pests. Treatments comprised two type of Si applications (Soil drench treatment and foliar spraying) with four Si concentrations (0, 0.5, 1 and 2%) of AB Yellow ® silicic acid formulation. The population density of B. tabaci and T. absoluta were studied weekly during the growth season. The results clearly demonstrated that Silicon applications significantly decreased the population of immature of both whiteflies and tomato leaf miner on tomato crop in the greenhouse; Si-Foliar spraying was more effective in reducing the population density of these key pests compared to Si- soil drench application.

scholarly journals The effect of host community functional traits on plant disease risk varies along an elevational gradient

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Fletcher W Halliday ◽  
Mikko Jalo ◽  
Anna-Liisa Laine
Keyword(s):  
Community Structure ◽  
Disease Risk ◽  
Environmental Gradients ◽  
Elevational Gradient ◽  
Host Community ◽  
Interactive Effects ◽  
Life History Strategies ◽  
Herbaceous Plant ◽  
Field Evidence ◽  
Increasing Temperature

Quantifying the relative impact of environmental conditions and host community structure on disease is one of the greatest challenges of the 21st century, as both climate and biodiversity are changing at unprecedented rates. Both increasing temperature and shifting host communities towards more fast-paced life-history strategies are predicted to increase disease, yet their independent and interactive effects on disease in natural communities remains unknown. Here, we address this challenge by surveying foliar disease symptoms in 220, 0.5 meter-diameter herbaceous plant communities along a 1100-meter elevational gradient. We find that increasing temperature associated with lower elevation can increase disease by (1) relaxing constraints on parasite growth and reproduction, (2) determining which host species are present in a given location, and (3) strengthening the positive effect of host community pace-of-life on disease. These results provide the first field evidence, under natural conditions, that environmental gradients can alter how host community structure affects disease.

scholarly journals Seasonal diversity of entomofauna, their impact and management practices in tomato fields in Meru district, Tanzania

2021 ◽  
Vol 21 (04) ◽  
pp. 17952-17971
Author(s):  
Gabriel Michael ◽  
◽  
AMS Nyomora ◽  
EF Mvungi ◽  
EM Sangu ◽  
...  
Keyword(s):  
Bemisia Tabaci ◽  
Management Practices ◽  
Insect Pests ◽  
Insect Pest ◽  
Tomato Leaf ◽  
Tuta Absoluta ◽  
Leaf Miner ◽  
Yield Reduction ◽  
Leaf Miners ◽  
Frequent Application

Tomato is a highly cultivated vegetable in Tanzania. The intensive tomato cultivation and production in Tanzania has resulted in high pests and diseases build-up. A survey to identify and quantify entomofauna diversity in different seasons and pest management practices in Meru District was conducted. In addition, a laboratory experiment was done to assess the effectiveness of commonly used pesticides SnowBecco (Thiamethoxam)and Belt (Flubendiamide) against two dominating insect pests, white flies (Bemisia tabaci (Gennadius, 1889)) and leaf miner (Tuta absoluta (Meyrick, 1917)), respectively. The results obtained revealed that, tomato fields in Meru District had significantly higher entomofauna build up during dry season than the rainy season (U0.05 (df, 24)= 45, p = 0.0441). More than 70% of all collected entomofauna were dominated by the whiteflies (Bemisia tabaci) and tomato leaf miners (Tuta absoluta) belonging to orders Hemiptera and Lepidoptera, respectively. It was also observed that, the common pesticides management practices were the use of pesticidal cocktail, broad spectrum insecticides, use of botanical pesticides, frequent application of pesticide and insecticides over dosage. Moreover, yield reduction due to whiteflies and tomato leaf miners infestation were observed in terms of reduced fruits number per plant (38 and 18.4%), fruit size (22.4 and 14.2%), and fruits weight per plant by 43.6 and 26.2%, for Bemisia tabaci and Tuta absoluta, respectively. The study showed that the recommended doses in both tested insecticides caused significant pest mortality (F0.05 (df, 19) = 4.367, p = 0.0199) and (F0.05(df, 19) = 4.761, p = 0.0147) for B. tabaci and T. absoluta, respectively, within a specified period of time. The results suggest that high insect pest infestations could be caused by factors other than development of insecticidal tolerance including inappropriate identification of insect pests due to lack of training, and inappropriate selection and application of insecticides. Consequently, frequent application of broad spectra insecticides not only increases production expenses but also disrupts agroecosystem by killing beneficial entomofauna and disrupting soil organisms that are susceptible to insecticide toxicity.

scholarly journals Plant responses to climate and relationships with pasture persistence

2011 ◽  
Vol 15 ◽  
pp. 99-107
Author(s):  
D.F. Chapman ◽  
G.R. Edwards ◽  
Z.N. Nie
Keyword(s):  
Plant Breeding ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Climatic Factors ◽  
Insect Pest ◽  
Plant Responses ◽  
Negative Effects ◽  
Term Survival ◽  
Variable Environment ◽  
Resource Limitations

Relationships between climatic factors and persistence of grazed perennial ryegrass and white clover pastures in New Zealand are reviewed from an ecophysiological perspective. 'Persistence' is defined in terms of physical survival of plants of sown cultivars: the effects of climate on plant populations are considered. Substantial information is available on the population dynamics of perennial ryegrass and white clover in different climatic environments, particularly on the influence of drought on populations. Substantial, direct negative effects of drought on the density of perennial ryegrass tillers and white clover stolons have been recorded, though populations have generally recovered after release from drought conditions. Otherwise, the effects of climaterelated resource limitations on population size are more likely to be interactive, working in concert with other factors such as management, soil fertility and insect pest challenges to limit the capacity of homeostatic responses to restore the optimal (for long term survival) balance between above- and below-ground resources. The relative extent to which more recent cultivars of perennial ryegrass are able to tolerate multiple, simultaneous resource limitations compared to older cultivars (with different phenotype) is considered, but there is little direct evidence on this matter. Issues that should be considered in future pasture persistence research are identified and discussed. One of these concerns is the persistence of trait expression in cultivars bred for specific traits. More research on this topic is warranted, since molecular plant breeding techniques are strongly based on trait manipulation, and genotype x environment interactions can be expected in the spatially and temporally variable environment of grazed pastures. Keywords: drought, ecology, plant breeding, ryegrass, white clover

scholarly journals Interaction Effects of Air Pollution and Climatic Factors on Circulatory and Respiratory Mortality in Xi’an, China between 2014 and 2016

2020 ◽  
Vol 17 (23) ◽  
pp. 9027
Author(s):  
Kingsley Katleho Mokoena ◽  
Crystal Jane Ethan ◽  
Yan Yu ◽  
Asenso Theophilus Quachie
Keyword(s):  
Air Pollution ◽  
Time Series ◽  
Relative Risk ◽  
Relative Humidity ◽  
Quality Index ◽  
Climatic Factors ◽  
Interaction Effects ◽  
Interactive Effects ◽  
Respiratory Mortality ◽  
Distributed Lag

Several studies have reported that air pollution and climatic factors are major contributors to human morbidity and mortality globally. However, the combined interactive effects of air pollution and climatic factors on human health remain largely unexplored. This study aims to investigate the interactive effects of air pollution and climatic factors on circulatory and respiratory mortality in Xi’an, China. Time-series analysis and the distributed lag non-linear model (DLNM) were employed as the study design and core statistical method. The interaction relative risk (IRR) and relative excess risk due to interaction (RERI) for temperature and Air Quality Index (AQI) interaction on circulatory mortality were 0.973(0.969, 0.977) and −0.055(−0.059, −0.048), respectively; while for relative humidity and AQI interaction, 1.098(1.011, 1.072) and 0.088(0.081, 0.107) respectively, were estimated. Additionally, the IRR and RERI for temperature and AQI interaction on respiratory mortality were 0.805(0.722, 0.896) and −0.235(−0.269, −0.163) respectively, while 1.008(0.965, 1.051) and −0.031(−0.088, 0.025) respectively were estimated for relative humidity and AQI interaction. The interaction effects of climatic factors and AQI were synergistic and antagonistic in relation to circulatory and respiratory mortality, respectively. Interaction between climatic factors and air pollution contributes significantly to circulatory and respiratory mortality.

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