Spatial Distribution of Mealybugs (Hemiptera: Coccomorpha: Coccoidea) in the Root System of Pruned and Non-pruned Coffea arabica Trees

2019 ◽  
Author(s):  
Flor E Acevedo ◽  
Mauricio Jiménez ◽  
Juan P Pimentel ◽  
Pablo Benavides
Keyword(s):  
Spatial Distribution ◽  
Root Biomass ◽  
Developmental Stages ◽  
Control Strategies ◽  
First Year ◽  
In Planta ◽  
Coffee Tree ◽  
Root Death ◽  
Root Sampling ◽  
Tree Pruning

Abstract Root mealybugs are important pests of coffee in many parts of the world. Despite the importance of these insects very little is known about their biology, ecology, and coffee susceptibility at different developmental stages. This study determined the effects of coffee tree pruning on root biomass, the number and within-plant spatial distribution of root-associated mealybugs, and weed-mealybug associations near coffee root systems. We made destructive root sampling of pruned and non-pruned coffee trees every 3 mo during the first-year post-pruning. In each sampling, we quantified coffee root biomass, and the number and spatial distribution of mealybug genera. Mealybugs feeding on weed roots were sampled every 2 wk for the duration of 10 wk. We identified the mealybug genera Puto Signoret (Hemiptera: Putoidae), Dysmicoccus Ferris (Hemiptera: Pseudococcidae), Ripersiella Tinsley (Hemiptera: Rhizoecidae), Rhizoecus Künckel (Hemiptera: Rhizoecidae), and Geococcus Green (Hemiptera: Pseudococcidae) associated with coffee roots. Species from Puto and Ripersiella were the most abundant representing 91% of the total mealybugs found in non-pruned trees, and 75% of the ones found in pruned trees. Coffee tree pruning reduced root biomass by 60% and mealybug numbers during the first 9 mo post-pruning. Mealybugs associated with a variety of weeds growing near coffee roots increased their number during the first 6 wk after coffee pruning. Our results suggest that coffee tree pruning causes a high percentage of root death, which correlates with a decrease of root-associated mealybugs that probably migrate to weed roots. This study provides basic information for designing mealybug control strategies in pruned coffee trees. Las cochinillas de las raíces son plagas importantes del café en varias partes del mundo. A pesar de la importancia de estos insectos se conoce muy poco sobre su biologia, ecología y sobre la susceptibilidad de plantas de café en diferentes etapas de desarrrollo. Este estudio determinó el efecto de la poda de árboles de café en la biomasa de raíces, el número y la distribución espacial in-planta de cochinillas asociadas a las raíces, y asociaciones de cochinillas con arvenses en el plato de los árboles de café. Se realizaron muestreos destructivos de raíces en árboles de café podados y no podados cada tres meses durante el primer año después de la poda. Las cochinillas alimentándose de raíces de arvenses fueron muestreadas cada dos semanas durante diez semanas. En cada muestreo se cuantificó la biomasa de raíces de café, se identificó el género de cochinillas, su cantidad y su distribución espacial. Se identificaron los géneros de cochinillas Puto Signoret (Hemiptera: Putoidae), Dysmicoccus Ferris (Hemiptera: Pseudoccocidae), Ripersiella Tinsley (Hemiptera: Rhizoecidae), Rhizoecus Künckel (Hemiptera: Rhizoecidae), y Geococcus Green (Hemiptera: Pseudococcidae) asociados a raíces de café. Especies de Puto y Ripersiella fueron las más abundantes representando el 91% del total de cochinillas encontradas en árboles no podados y el 75% de aquellas encontradas en árboles podados. La poda de árboles de café redujo la biomasa de raíces en un 60% y el número de cochinillas durante los primeros nueve meses después de la poda. Las cochinillas asociadas a varias especies de arvenses presentes en los platos de los árboles de café incrementaron su número durante las primeras seis semanas después de la poda de los árboles. Los resultados de este estudio sugieren que la poda de árboles de café causa una alta muerte de raíces, lo cual se correlaciona con una reducción en las cochinillas quienes probablemente migran hacia las raíces de las arvenses. Este estudio proporciona información básica para el diseño de estrategias de control de cochinillas en árboles de café podados.

Spatial distribution of roots, nematode populations and root necrosis in highland banana in Uganda

Nematology ◽  
2004 ◽  
Vol 6 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Imelda Kashaija ◽  
Beverley McIntyre ◽  
Henry Ssali ◽  
Fred Kizito
Keyword(s):  
Spatial Distribution ◽  
Damage Assessment ◽  
Root Biomass ◽  
Management Practices ◽  
Nematode Species ◽  
Horizontal Distribution ◽  
Radopholus Similis ◽  
Root Necrosis ◽  
Root Sampling ◽  
Distribution Of Roots

Abstract Banana root distribution, nematodes, and necrosis were assessed in banana (Musa AAA) monoculture and banana-legume intercrops in Uganda, with the aim of establishing their relationship in order to enhance decision making with regard to management practices and sampling for nematode population and damage assessment. The intercrops had no effect on the vertical or the horizontal distribution of banana roots and nematodes. Approximately 90% of the root biomass was in the upper 0.3 m and none was below 0.7 m. Within 0.5 m of the banana mat, the majority of root mass was in the surface 0.15 m, but outside this radius more were found from 0.15-0.3 m. This spatial distribution suggests that fertiliser applications would be most effectively applied within a 0.5 m radius of the banana mat. Nematode species and root necrosis were uniformly distributed horizontally on the roots; vertical distribution differed among species. Significantly larger populations of Radopholus similis were found in the upper 0.3 m; none was present below 0.5 m. Helicotylenchus multicinctus and Pratylenchus goodeyi were found throughout the rooting profile; H. multicinctus density being high in the upper 0.5 m, while P.goodeyi was generally low throughout. More root necrosis was noted in the upper 0.3 m, coinciding with the greatest population density of R. similis and the greatest amount of root biomass. The spatial distribution of nematodes indicates that root sampling and nematicide application should be concentrated within 0.5 m of the banana mat.

scholarly journals Temporal Dynamics of ‘Ca. Phytoplasma mali’ Load in the Insect Vector Cacopsylla melanoneura

Insects ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 592
Author(s):  
Valentina Candian ◽  
Monia Monti ◽  
Rosemarie Tedeschi
Keyword(s):  
Host Plants ◽  
Developmental Stages ◽  
Temporal Dynamics ◽  
Control Strategies ◽  
Vector Competence ◽  
Insect Vector ◽  
Life Stages ◽  
Candidatus Phytoplasma Mali ◽  
High Infection ◽  
Cacopsylla Melanoneura

The transmission of phytoplasmas is the result of an intricate interplay involving pathogens, insect vectors and host plants. Knowledge of the vector’s competence during its lifespan allows us to define more sustainable well-timed control strategies targeted towards the most worrisome life stages. We investigated the temporal dynamics of ‘Candidatus Phytoplasma mali’ load in Cacopsylla melanoneura in the different developmental stages in Northwest Italy. The phytoplasma load in the vector was evaluated in overwintering adults, nymphs and newly emerged adults after different acquisition access periods. Moreover, we followed the multiplication of the phytoplasma during the aestivation and the overwintering period on conifers. Our results confirmed the ability of remigrants to retain the phytoplasma until the end of winter. We also highlighted the high acquisition efficiency and vector competence, based on phytoplasma load, of nymphs and newly emerged adults. Therefore, particular attention should be paid to the management of overwintered C. melanoneura as soon as they return to the orchards, but also to newly emerged adults, particularly in orchards with a high infection rate and when the migration to conifers is delayed.

scholarly journals Development of the first georeferenced map of Rhipicephalus (Boophilus) spp. in Mexico from 1970 to date and prediction of its spatial distribution

2018 ◽  
Vol 13 (1) ◽  
Author(s):  
Yazmin Alcala-Canto ◽  
Juan Antonio Figueroa-Castillo ◽  
Froylán Ibarra-Velarde ◽  
Yolanda Vera-Montenegro ◽  
María Eugenia Cervantes-Valencia ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Environmental Variables ◽  
Control Strategies ◽  
Integrated Control ◽  
Area Under The Curve ◽  
Entropy Method ◽  
Distribution Model ◽  
Economic Losses ◽  
Precipitation Seasonality ◽  
Epidemiological Risk

The tick genus Ripicephalus (Boophilus), particularly R. microplus, is one of the most important ectoparasites that affects livestock health and considered an epidemiological risk because it causes significant economic losses due, mainly, to restrictions in the export of infested animals to several countries. Its spatial distribution has been tied to environmental factors, mainly warm temperatures and high relative humidity. In this work, we integrated a dataset consisting of 5843 records of Rhipicephalus spp., in Mexico covering close to 50 years to know which environmental variables mostly influence this ticks’ distribution. Occurrences were georeferenced using the software DIVA-GIS and the potential current distribution was modelled using the maximum entropy method (Maxent). The algorithm generated a map of high predictive capability (Area under the curve = 0.942), providing the various contribution and permutation importance of the tested variables. Precipitation seasonality, particularly in March, and isothermality were found to be the most significant climate variables in determining the probability of spatial distribution of Rhipicephalus spp. in Mexico (15.7%, 36.0% and 11.1%, respectively). Our findings demonstrate that Rhipicephalus has colonized Mexico widely, including areas characterized by different types of climate. We conclude that the Maxent distribution model using Rhipicephalus records and a set of environmental variables can predict the extent of the tick range in this country, information that should support the development of integrated control strategies.

Probing the application of OmpA-derived peptides to disrupt the acquisition of ‘Candidatus Liberibacter asiaticus’ by Diaphorina citri

2021 ◽  
Author(s):  
Marcus Vinicius Merfa e Silva ◽  
Eduarda Regina Fischer ◽  
Mariana de Souza e Silva ◽  
Carolina Sardinha Francisco ◽  
Helvécio Coletta-Filho ◽  
...  
Keyword(s):  
Control Strategies ◽  
Insect Vector ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
In Planta ◽  
Host Interaction ◽  
Vector Population ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus ◽  
Bacterial Outer Membrane

Huanglongbing (HLB) is currently the most devastating disease of citrus worldwide. Both bacteria ‘Candidatus Liberibacter asiaticus’ (CLas) and ‘Ca. Liberibacter americanus’ (CLam) are associated with HLB in Brazil, but with a strong prevalence of CLas over CLam. Conventionally, HLB management focuses on controlling the insect vector population (Diaphorina citri; also known as Asian citrus psyllid – ACP) by spraying insecticides, an approach demonstrated to be mostly ineffective. Thus, development of novel more efficient HLB control strategies is required. The multifunctional bacterial outer membrane protein OmpA is involved in several molecular processes between bacteria and their hosts and has been suggested as a target for bacterial control. Curiously, OmpA is absent in CLam in comparison to CLas, suggesting a possible role on host-interaction. Therefore, in the current study, we have treated ACPs with different OmpA-derived peptides aiming to evaluate the acquisition of CLas by the insect vector. Treatment of psyllids with 5 µM of Pep1, Pep3, Pep5 and Pep6 in artificial diet significantly reduced the acquisition of CLas, while increasing the concentration of Pep5 and Pep6 to 50 µM abolished this process. In addition, in planta treatment with 50 µM of Pep6 also significantly decreased the acquisition of CLas and sweet orange plants stably absorbed and maintained this peptide for as long as three months post the final application. Together, our results demonstrate the promising use of OmpA-derived peptides as a novel biotechnological tool to control CLas.

Developing e-learning for interprofessional education

2005 ◽  
Vol 11 (1_suppl) ◽  
pp. 102-104 ◽  
Author(s):  
Tunde Varga-Atkins ◽  
Helen Cooper
Keyword(s):  
Undergraduate Students ◽  
Interprofessional Education ◽  
Developmental Stages ◽  
First Year ◽  
Team Working ◽  
Content Development ◽  
E Learning ◽  
Development Evaluation ◽  
Online Format ◽  
The University

An evidence-based, interprofessional educational course involving first-year undergraduate students studying medicine, nursing, physiotherapy and occupational therapy has been piloted at the University of Liverpool. Part of the content was developed in an online format. To capture the development process and the e-learning writing experience, a focus group was arranged for the content writers. The session was audio-recorded and tapes were transcribed. All the data were subjected to thematic analysis. Twenty-three sub-themes were identified in the 72 comments. These were grouped under six themes, corresponding to the developmental stages of e-learning. The highest number of comments fell under the theme of preparation, followed by content development, evaluation, general design and structure, and finally delivery. Team working contributed to the success of the writing process, reflecting the theme of working interprofessionally.

Spatial distribution of coarse root biomass and carbon in a high-density olive orchard: effects of mechanical harvesting methods

Trees ◽  
2018 ◽  
Vol 32 (4) ◽  
pp. 919-931 ◽  
Author(s):  
A. Sorgonà ◽  
A. R. Proto ◽  
L. M. Abenavoli ◽  
A. Di Iorio
Keyword(s):  
Spatial Distribution ◽  
Root Biomass ◽  
High Density ◽  
Coarse Root ◽  
Olive Orchard

scholarly journals A joint spatial marked point process model for dengue and severe dengue in Medellin, Colombia.

2021 ◽  
Author(s):  
Mabel Carabali ◽  
Alexandra M. Schmidt ◽  
Berta N. Restrepo ◽  
Jay S. Kaufman
Keyword(s):  
Spatial Distribution ◽  
Process Model ◽  
Control Strategies ◽  
Marked Point ◽  
Local Level ◽  
Cross Sectional Study ◽  
Marked Point Process ◽  
Severe Dengue ◽  
Cross Sectional ◽  
Dengue Control

The spatial distribution of surveillance-reported dengue cases and severity are usually analyzed separately, assuming independence between the spatial distribution of non-severe and severe cases. Given the availability of data for the individual geo-location of surveillance-notified dengue cases, we conducted a cross-sectional study to model non-severe and severe dengue simultaneously, identifying the spatial patterns of dengue distribution, using individual and area level covariates within a hierarchical Bayesian model. Results showed that age and socioeconomic status were associated with dengue presence, and there was evidence of clustering for overall cases but not for severity. Our findings inform decision making to address the preparedness or implementation of dengue control strategies at the local level.

scholarly journals Modeling the role of mortality-based response triggers on the effectiveness of African swine fever control strategies

2021 ◽  
Author(s):  
Gustavo Machado ◽  
Trevor Farthing ◽  
Mathieu Andraud ◽  
Francisco Paulo Nunes Lopes ◽  
Cristina Lanzas
Keyword(s):  
Spatial Distribution ◽  
Animal Movement ◽  
Control Strategies ◽  
Virulent Strain ◽  
Animal Health ◽  
African Swine Fever ◽  
Multiscale Model ◽  
Case Scenario ◽  
Modeling Framework ◽  
Highly Virulent

African swine fever (ASF) is considered the most impactful transboundary swine disease. In the absence of effective vaccines, control strategies are heavily dependent on mass depopulation and movement restrictions. Here we developed a nested multiscale model for the transmission of ASF, combining spatially explicit network model of animal movements with a deterministic compartmental model for the dynamics of two ASF strains within-pixels of 3 km x 3 km, amongst the pig population in one Brazilian state. The model outcomes are epidemic duration, number of secondary infected farms and pigs, and distance of ASF spread. The model also predicted the spatial distribution of ASF epidemics. We analyzed quarantine-based control interventions in the context of mortality trigger thresholds for the deployment of control strategies. The mean epidemic duration of a moderately virulent strain was 11.2 days assuming the first infection is detected (best-case scenario) and 15.9 days when detection is triggered at 10 % mortality. For a highly virulent strain, the epidemic duration was 6.5 days and 13.1 days, respectively. The distance from the source to infected locations and the spatial distribution was not dependent on strain virulence. Under the best-case scenario, we projected an average number of infected farms of 18.79 farms and 23.77 farms for the moderate and highly virulent strains, respectively. At 10% mortality-trigger, the predicted number of infected farms was on average 48.28 farms and 42.97 farms, respectively. We also demonstrated that the establishment of ring quarantine zones regardless of size (i.e., 5 km, 15 km) was outperformed by backward animal movement tracking. The proposed modeling framework provides an evaluation of ASF epidemic potential, providing a ranking of quarantine-based control strategies that could assist animal health authorities in planning the national preparedness and response plan.

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