The concept of plant disease.

2021 ◽  
pp. 9-48
Author(s):  
Shou-Hua Wang
Keyword(s):  
Environmental Factors ◽  
Host Plant ◽  
Plant Pathogen ◽  
Plant Tissue ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Plant Diseases ◽  
Disease Cycle

Abstract This chapter focuses on the concept of plant disease, which is a condition where plant tissue or growth is damaged or altered by a pathogen or environmental factors. Information is also given on the interactions between the host plant, pathogen(s) and environmental factors (disease triangle), symptomatology, types of plant diseases, transmission, disease cycle and plant pathogens (fungi, bacteria, viruses and nematodes) and their control.

scholarly journals Microbial antagonists against plant pathogens in Iran: A review

2020 ◽  
Vol 5 (1) ◽  
pp. 404-440 ◽  
Author(s):  
Mehrdad Alizadeh ◽  
Yalda Vasebi ◽  
Naser Safaie
Keyword(s):  
Biological Control ◽  
Chemical Control ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Plant Diseases ◽  
Agricultural Products ◽  
Control Measures ◽  
Wide Range ◽  
Plant Disease Management ◽  
Published Research

AbstractThe purpose of this article was to give a comprehensive review of the published research works on biological control of different fungal, bacterial, and nematode plant diseases in Iran from 1992 to 2018. Plant pathogens cause economical loss in many agricultural products in Iran. In an attempt to prevent these serious losses, chemical control measures have usually been applied to reduce diseases in farms, gardens, and greenhouses. In recent decades, using the biological control against plant diseases has been considered as a beneficial and alternative method to chemical control due to its potential in integrated plant disease management as well as the increasing yield in an eco-friendly manner. Based on the reported studies, various species of Trichoderma, Pseudomonas, and Bacillus were the most common biocontrol agents with the ability to control the wide range of plant pathogens in Iran from lab to the greenhouse and field conditions.

scholarly journals Cooperation of two opposite flagella allows high-speed swimming and active turning in zoospores

2021 ◽  
Author(s):  
Quang D. Tran ◽  
Eric Galiana ◽  
Philippe Thomen ◽  
Céline Cohen ◽  
François Orange ◽  
...  
Keyword(s):  
Host Plant ◽  
High Speed ◽  
Plant Pathogens ◽  
Plant Diseases ◽  
Active Process ◽  
Motility Pattern ◽  
Anterior Flagellum ◽  
Active Turning ◽  
Posterior Flagellum ◽  
Run And Tumble

Phytophthora species cause diseases in a large variety of plants and represent a serious agricultural threat, leading, every year, to multibillion dollar losses. Infection occurs when these biflagellated zoospores move across the soil at their characteristic high speed and reach the roots of a host plant. Despite the relevance of zoospore spreading in the epidemics of plant diseases, it is not known how these zoospores swim and steer with two opposite beating flagella. Here, combining experiments and modeling, we show how these two flagella contribute to generate thrust when beating together, and identify the mastigonemes-attached anterior flagellum as the main source of thrust. Furthermore, we find that steering involves a complex active process, in which the posterior flagellum is stopped, while the anterior flagellum keeps on beating, as the zoospore reorients its body. Our study is a fundamental step towards a better understanding of the spreading of plant pathogens’ motile forms, and shows that the motility pattern of these biflagellated zoospores represents a distinct eukaryotic version of the celebrated “run-and-tumble” motility class exhibited by peritrichous bacteria.

scholarly journals Biochar and Trichoderma spp. in management of plant diseases caused by soilborne fungal pathogens: a review and perspective

2021 ◽  
Vol 10 (15) ◽  
pp. e296101522465
Author(s):  
Erika Valente de Medeiros ◽  
Lucas Figueira da Silva ◽  
Jenifer Sthephanie Araújo da Silva ◽  
Diogo Paes da Costa ◽  
Carlos Alberto Fragoso de Souza ◽  
...  
Keyword(s):  
Soil Properties ◽  
Fungal Pathogens ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Plant Diseases ◽  
Management Tool ◽  
Production Plant ◽  
Trichoderma Spp ◽  
Health Concept ◽  
Plant Disease Management

A better understanding of the use of biochar with Trichoderma spp. (TRI), considered the most studied tool for biological control, would increase our ability to set priorities. However, no studies exist using the two inputs on plant disease management. Here, we hypothesized that biochar and TRI would be used for the management of soilborne plant pathogens, mainly due to changes in soil properties and its interactions. To test this hypothesis, this review assesses papers that used biochar and TRI against plant diseases and we summarize the handling mechanisms for each input. Biochar acts by mechanisms: induction to plant resistance, sorption of allelopathic and fungitoxic compounds, increase of beneficial microorganisms, changes the soil properties that promote health and nutrient availability. Trichoderma as biocontrol agents by different mechanisms: mycoparasitism, enzyme and secondary metabolic production, plant promoter agent, natural decomposition agent, and biological agent of bioremediation. Overall, our findings expand our knowledge about the reuse of wastes transformed in biochar combined with Trichoderma has potential perspective to formulate products as alternative management tool of plant disease caused by soilborne fungal pathogen and add important information that can be suitable for development of strategy for use in the global health concept.

scholarly journals The Probing Behavior Component of Disease Transmission in Insect-Transmitted Bacterial Plant Pathogens

Insects ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 212 ◽  
Author(s):  
Timothy A. Ebert
Keyword(s):  
Host Plant ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Disease Transmission ◽  
Plant Pathogens ◽  
Management Strategies ◽  
Resistance Mechanism ◽  
Electrical Circuit ◽  
Plant Diseases ◽  
Candidatus Liberibacter

Insects can be effective vectors of plant diseases and this may result in billions of dollars in lost agricultural productivity. New, emerging or introduced diseases will continue to cause extensive damage in afflicted areas. Understanding how the vector acquires the pathogen and inoculates new hosts is critical in developing effective management strategies. Management may be an insecticide applied to kill the vector or a host plant resistance mechanism to make the host plant less suitable for the vector. In either case, the tactic must act before the insect performs the key behavior(s) resulting in either acquisition or transmission. This requires knowledge of the timing of behaviors the insect uses to probe the plant and commence ingestion. These behaviors are visualized using electropenetrography (EPG), wherein the plant and insect become part of an electrical circuit. With the tools to define specific steps in the probing process, we can understand the timing of acquisition and inoculation. With that understanding comes the potential for more relevant testing of management strategies, through insecticides or host plant resistance. The primary example will be Candidatus Liberibacter asiaticus transmitted by Diaphorina citri Kuwayama in the citrus agroecosystem, with additional examples used as appropriate.

scholarly journals Natural Plant Products as Eco-friendly Fungicides for Plant Diseases Control- A Review

2016 ◽  
Vol 14 (1) ◽  
pp. 134-141 ◽  
Author(s):  
M Zaker
Keyword(s):  
Plant Disease ◽  
Plant Pathogens ◽  
Chemical Compounds ◽  
Plant Diseases ◽  
Agricultural Products ◽  
Higher Plant ◽  
Natural Plant ◽  
Plant Products ◽  
Near Future ◽  
Chemical Pesticides

The use of chemical pesticides for controlling various plant diseases is still a common practice especially in developing countries. Although with the application of chemical fungicides, plant diseases can be controlled but the hazardous impacts of such products in human health and environment are well known. Moreover, with their excess applications pest resistance may exist. Natural plant products have been found effective in plant disease managements and could be safely incorporated as suitable alternatives for synthetic fungicides. It is estimated that there are more than 250,000 higher plant species on earth that can be evaluated for their antimicrobial bioactive chemical compounds. During last several decades researchers have evaluated plant extracts and oils against plant pathogens, valuable results have been achieved and some commercially botanical formulations have been prepared and marketed. If we are supposed to move toward production of safer agricultural products, more attention and effort are still needed for production of more commercially botanical fungicides in the near future. The organic agriculture cannot rely on a limited number of commercially pesticides of natural origin, therefore it seems that more researches in formulating more commercially botanical products as fungicides are still needed.The Agriculturists 2016; 14(1) 134-141

scholarly journals Selection of antagonists for biocontrol of Xanthomonas euvesicatoria

2020 ◽  
pp. 181-189
Author(s):  
Ivana Pajcin ◽  
Vanja Vlajkov ◽  
Dragoljub Cvetkovic ◽  
Maja Ignjatov ◽  
Mila Grahovac ◽  
...  
Keyword(s):  
Biological Control ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Plant Diseases ◽  
Bacterial Spot ◽  
Cultivation Medium ◽  
Microbial Strains ◽  
Xanthomonas Euvesicatoria ◽  
Selection Of

Xanthomonas euvesicatoria is a worldwide causer of pepper bacterial spot, a bacterial plant disease responsible for massive losses of fresh pepper fruits. Considering the current problems in management of bacterial plant diseases, biological control using antagonistic microbial strains with high potential for plant pathogens suppression emerges as a possible solution. The aim of this study was to select suitable antagonists for suppression of X. euvesicatoria among the bacteria, yeast and fungi from the genera Pseudomonas, Lactobacillus, Saccharomyces and Trichoderma, based on in vitro antimicrobial activity testing using the diffusion disc method. The results of this study have revealed that cultivation broth samples of the antagonists Lactobacillus MK3 and Trichoderma reseii QM 9414, as well as supernatant samples of the antagonist Pseudomonas aeruginosa I128, have showed significant potential to be applied in biological control of X. euvesicatoria. Further research would be required to formulate suitable cultivation medium and optimize bioprocess conditions for production of the proposed pepper bacterial spot biocontrol agents.

scholarly journals RNA interference approaches for plant disease control

BioTechniques ◽  
2020 ◽  
Vol 69 (6) ◽  
pp. 469-477
Author(s):  
Yen-Wen Kuo ◽  
Bryce W Falk
Keyword(s):  
Rna Interference ◽  
Disease Control ◽  
Crop Production ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Control Plant ◽  
Cost Effective ◽  
Plant Diseases ◽  
Natural Ecosystems ◽  
Plant Disease Control

Plant diseases caused by a variety of pathogens can have severe effects on crop plants and even plants in natural ecosystems. Despite many effective conventional approaches to control plant diseases, new, efficacious, environmentally sound and cost-effective approaches are needed, particularly with our increasing human population and the effects on crop production and plant health caused by climate change. RNA interference (RNAi) is a gene regulation and antiviral response mechanism in eukaryotes; transgenic and non transgenic plant-based RNAi approaches have shown great effectiveness and potential to target specific plant pathogens and help control plant diseases, especially when no alternatives are available. Here we discuss ways in which RNAi has been used against different plant pathogens, and some new potential applications for plant disease control.

The aerial dispersal of the pathogens of plant disease

1983 ◽  
Vol 302 (1111) ◽  
pp. 451-462 ◽  
Keyword(s):  
Life Cycle ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Random Distribution ◽  
Weak Link ◽  
Plant Diseases ◽  
Classic Model ◽  
Aerial Dispersal

The classic model, the logistic, often fits the course of an epidemic of plant disease although the assumptions of propagules proportional to infected plants and random distribution of the propagules are violated. When a thorough simulation of the life cycle of a pathogen is composed, knowledge of its dissemination is the weak link. Although some plant diseases are caused by bacteria and viruses, some pathogens are not airborne and some plants grow indoors; plant pathogens are distinguished by the prevalence of fungi and the durability of their propagules; their hosts are usually exposed outdoors; the pathogens are unaided in their take-off by coughing or sneezing and their landing by breathing; and they are not carried by perambulating hosts. Thus investigations and models of dissemination of plant pathogens concentrate on ways in which spores can be detached and become airborne, on hardiness and relatively long flight and on settling or impacting on foliage outdoors.

scholarly journals Biosensor Technologies for Early Detection and Quantification of Plant Pathogens

2021 ◽  
Vol 9 ◽  
Author(s):  
Kazbek Dyussembayev ◽  
Prabhakaran Sambasivam ◽  
Ido Bar ◽  
Jeremy C. Brownlie ◽  
Muhammad J. A. Shiddiky ◽  
...  
Keyword(s):  
Disease Management ◽  
Early Detection ◽  
Plant Pathogen ◽  
Pathogen Detection ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Financial Burden ◽  
Management Strategies ◽  
Disease Diagnostics ◽  
Plant Pathogen Detection

Plant pathogens are a major reason of reduced crop productivity and may lead to a shortage of food for both human and animal consumption. Although chemical control remains the main method to reduce foliar fungal disease incidence, frequent use can lead to loss of susceptibility in the fungal population. Furthermore, over-spraying can cause environmental contamination and poses a heavy financial burden on growers. To prevent or control disease epidemics, it is important for growers to be able to detect causal pathogen accurately, sensitively, and rapidly, so that the best practice disease management strategies can be chosen and enacted. To reach this goal, many culture-dependent, biochemical, and molecular methods have been developed for plant pathogen detection. However, these methods lack accuracy, specificity, reliability, and rapidity, and they are generally not suitable for in-situ analysis. Accordingly, there is strong interest in developing biosensing systems for early and accurate pathogen detection. There is also great scope to translate innovative nanoparticle-based biosensor approaches developed initially for human disease diagnostics for early detection of plant disease-causing pathogens. In this review, we compare conventional methods used in plant disease diagnostics with new sensing technologies in particular with deeper focus on electrochemical and optical biosensors that may be applied for plant pathogen detection and management. In addition, we discuss challenges facing biosensors and new capability the technology provides to informing disease management strategies.

scholarly journals Meta-Learning for Few-Shot Plant Disease Detection

Foods ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2441
Author(s):  
Liangzhe Chen ◽  
Xiaohui Cui ◽  
Wei Li
Keyword(s):  
Neural Networks ◽  
Crop Production ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Feature Matching ◽  
Apple Scab ◽  
Plant Diseases ◽  
Deep Impact ◽  
Meta Learning ◽  
Adaptive Processes

Plant diseases can harm crop growth, and the crop production has a deep impact on food. Although the existing works adopt Convolutional Neural Networks (CNNs) to detect plant diseases such as Apple Scab and Squash Powdery mildew, those methods have limitations as they rely on a large amount of manually labeled data. Collecting enough labeled data is not often the case in practice because: plant pathogens are variable and farm environments make collecting data difficulty. Methods based on deep learning suffer from low accuracy and confidence when facing few-shot samples. In this paper, we propose local feature matching conditional neural adaptive processes (LFM-CNAPS) based on meta-learning that aims at detecting plant diseases of unseen categories with only a few annotated examples, and visualize input regions that are ‘important’ for predictions. To train our network, we contribute Miniplantdisease-Dataset that contains 26 plant species and 60 plant diseases. Comprehensive experiments demonstrate that our proposed LFM-CNAPS method outperforms the existing methods.

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