Biocontrol of Plant Pathogens

A faba bean rhizospheric Pseudomonas aeruginosa isolate RZ9 was used for studying its antifungal activity and protecting effects of faba bean and common bean against the root pathogen Fusarium culmorum strain MZB47. The dual culture tests showed that RZ9 inhibits MZB47 in vitro growth by 56%. When mixing RZ9 cell suspension with MZB47 macroconidia at equal proportion, the macroconidia viability was reduced with 70%. Pathogenicity tests conducted in sterile conditions showed that MZB47 caused an intense root rotting in faba bean ‘Aquadulce’ plantlets and a slight level in common bean ‘Coco blanc’. This was associated to significant decreases in plant growth only in ‘Aquadulce’, reducing shoot dry weight (DW) by 82% and root DW by 70%. In soil samples, MZB47 caused severe root rotting and induced significant decreases in shoot DW (up to 51%) and root DW (up to 60%) for both beans. It was associated to a decrease in nodule number by 73% and 52% for faba bean and common bean, respective...

O uso de micro-organismos na agricultura está cada vez ganhando mais espaço nas fazendas de todo o Brasil. Algumas espécies de bactérias e fungos possuem inúmeros benefícios, seja controlando pragas e doenças, ou promovendo o crescimento de plantas por meio da fixação biológica de nitrogênio atmosférico e pela solubilização de nutrientes. A produção “on farm”, ou seja, produção de micro-organismos na própria fazenda, foi regulamentada em 2024 por meio da Lei de Bioinsumos (Lei nº 15.070/2024), criando um marco histórico na agricultura do país.
Diante de tantos acontecimentos, o estabelecimento de procedimentos básicos para a produção e o controle de qualidade de insumos biológicos é fundamental. Esse manual visa cobrir essa lacuna, com metodologias atuais e de fácil execução, com informações sobre a morfologia, os mecanismos de ação, a produção e o controle de qualidade das principais bactérias e fungos utilizados no controle de pragas e doenças agrícolas. Portanto, esse manual é destinado para estudantes, técnicos, pesquisadores e profissionais das Ciências Biológicas e Agrárias que possuam interesse em se aprofundar no conhecimento de bioinsumos de origem microbiana.

Antifungal activity of commercial sample of Boswellia carteri essential oil against selected micromycetes was evaluated in vitro using a microatmosphere method. When compared with biocide Sanosil S003, used as positive control, the tested essential oil showed moderate antifungal activity. The most susceptible fungi to oil treatment were Stachybotrys chartarum and Trichotecium roseum. For both fungi, mycelia growth inhibition of 85% was recorded at oil concentration of 100 ?L mL-1. The tested essential oil caused inhibition of S. chartarum sporulation as well as depigmentation of conidi?, which is very significant since melanin contributes to virulence, survival and endurance of pathogenic fungi spores. Aspergillus niger was the least susceptible isolate to essential oil treatment. Mycelial growth of this fungus was not inhibited by any oil concentrations used in the experiment.

Arbuscular mycorrhizal associations imply a remarkable reprogramming of functions in both plant and fungal symbionts. The consequent alterations on plant physiology have a clear impact on the plant response to biotic stresses. In this chapter we discuss the effects of the mycorrhizal symbiosis on plant susceptibility/resistance to potential deleterious organisms, including root and shoot pathogens, root parasitic plants and phytophagous insects, highlighting the mechanisms that may be operating in each particular case. Special attention is given to the modulation of plant defence responses in mycorrhizal systems, as it may affect all interactions. Finally we focus on the priming of jasmonate regulated plant defence mechanisms that seem to mediate the induction of resistance by arbuscular mycorrhizas.

Faba bean (Vicia faba L.) is one of the oldest domesticated food legumes that have been cultivated for at least 5000 years. It is a multi-purpose crop that plays an important role in the socio-economic life of farming communities in Ethiopia. Chocolate spot disease, caused by Botrytis fabae is one of the yield limiting factors of this crop resulting in yield losses up to 68% in Ethiopia. A field survey was conducted in Tach Gayint district South Gondar Administrative Zone during the 2020/2021 main cropping season to assess the importance of the chocolate spot disease of faba bean. A total of 60 faba bean farmer fields were assessed in six (6) Kebele Administrations and most farmer fields were affected by chocolate spots. But the status of disease incidence and severity was varied. Significant differences among locations were observed due to altitude, soil type, planting density, date of planting, crop growth stages and farm history of the fields. Independent variables like Altitude, farm history, crop growth stage, date of planting and planting density were significantly associated with both disease incidence and severity when entered first and last into a model. The finding indicates that the lowest plant density and late planting of the crop reduce the incidence and severity of the disease.

Rice sheath rot, caused by Sarocladium oryzae, is a devastating disease threatening rice production worldwide, with yield losses ranging from 9.6 per cent to 85 per cent. Conventional reliance on synthetic fungicides has raised concerns about environmental sustainability and health safety, prompting the exploration of eco-friendly alternatives. This study investigates the in vitro efficacy of native antagonistic bio-agents, specifically Trichoderma spp. and Pseudomonas spp., against Sarocladium oryzae. Rhizospheric soil samples were collected to isolate and identify bio-agents, which were then tested using the dual culture method. Results revealed significant pathogen inhibition, with Trichoderma isolate Tr-1 achieving the highest inhibition rate (76.72%) among the Trichoderma isolates and in Pseudomonas isolates Ps-1 (61.21%) showed the significant inhibition. These findings highlight the potential of native bio-agents as sustainable, environmentally friendly alternatives to chemical fungicides, offering a promising strategy
for integrated disease management in rice cultivation and advancing organic farming practices.

This study delves into the intriguing role of bioagents in tackling Fusarium wilt in lentil (Fusarium oxysporum f.sp. lentis) by stimulating plant defense mechanisms, reducing wilt incidence, and regulating growth factors to boost yield. Biocontrol agents: Trichoderma harzianum (Th-14) (PB1), Pseudomonas fluorescens (Psf 173) (PB2), or a mix of the two (PB3) were used at both in vitro and in vivo at different doses (6 g, 10 g, and 15 g per kg seed). Bioagent, Pseudomonas fluorescens (Strain Psf 173) exhibited a significant 70 percent inhibition of the pathogen mycelium radial growth along with the significant decrease in the wilt disease and an increase in yield in the field after the seed treatment. The plant defense-related enzymes such as PAL, PO, PPO, and catalase also increased many folds. Thus, demonstrated a promising result in controlling Fusarium wilt in lentil in organic farming.

Hydrangea macrophylla cultivars widely differ in their relative abundance and duration of flower production. However, the reasons for this variation are not well understood. This study consisted of 3 experiments to determine where and when floral induction occurred on commercial cultivars and in the newer re-flowering hydrangeas. It also determined the patterns of floral development of the induced buds and the effect of different pruning times on growth and development of the plants. In evaluations of dormant shoots in 18 cultivars, flower development was very consistent in terminal buds, and occurred in 100% of the terminal buds for all of the cultivars with the exception of 'Ayesha' (33%). In contrast, lateral buds showed a wide variation in flower development among different genotypes; and the percentage of induction range from 0 to 100%. Flower development was more advanced in terminal than in lateral buds. In the second experiment examining shoots throughout an annual cycle, cultivars had floral primordia initiated in lateral buds at the first sampling period prior to receiving cold or short days. The degree of induction and development varied according to the cultivar and evaluation (harvest) period. Although, differences were found among some cultivars and evaluation periods, most of the cultivars reached their maximum flower potential and floral development by the time they reached the dormant period (leaf abscission), with no further induction or development during the quiescent period. The results suggested that some cultivars have minimal or no photoperiodic/temperature requirements to induce flowering. These studies indicated that genotypic variation in terminal and lateral floral induction, differences in floral development, and low or minimal inductive conditions (e.g. temperature, photoperiod) required for some cultivars may explain the ability of some cultivars to have a greater abundance and duration of flower production. The information provided for this study could aid the industry and gardeners in developing cultural practices (chemical treatments or pruning practices) to promote lateral bud-break throughout the growing season, thereby enhancing the production of flowers and extending the blooming season of some cultivars.

This study evaluated the potential of a biostimulant derived from Inula viscosa (fresh and dried leaves) to enhance
vegetable plant growth and resistance to phytopathologies such as Botrytis cinerea and downy mildew. The experiments
were conducted in May 2024 in CREA-OF greenhouses (Pescia, PT) on Brussels sprout and early Verona broccoli plants. Six
treatment groups were tested: (i) control (water-irrigated, pre-fertilized substrate), (ii) algae, (iii) mixed microorganisms +
Inula viscosa fresh leaves + algae, (iv) mixed microorganisms + Inula viscosa dried leaves + algae, (v) mixed microorganisms
+ herbal tea of dried Inula viscosa leaves + algae, and (vi) mixed microorganisms + macerated Inula viscosa + algae. Data
were collected on November 15, 2024, including measurements of plant height, leaf number, total leaf area, root length,
aerial and root biomass, and shelf life. The efficacy against Botrytis and downy mildew was assessed based on the number
of affected plants. Treatments involving dried Inula viscosa leaves and herbal tea significantly improved both vegetative
and root growth in both plant species. In Brussels sprouts, the INUS treatment increased vegetative growth by 46.36% and
root growth by 32.46% compared to the control. In Verona broccoli, vegetative growth increased by 30.12% and root
growth by 24.22% with the INUS treatment. Other treatments also enhanced plant growth, albeit to a lesser extent.
Notably, the dried leaf treatment extended shelf life by 7.45% in Brussels sprouts and 6.88% in Verona broccoli.
Furthermore, the INUS treatment reduced Botrytis incidence by 83% and downy mildew by 88.25% in Brussels sprouts. In
Verona broccoli, reductions were 79.14% and 91.25%, respectively. This study highlights the potential of Inula viscosa as
an innovative biostimulant for sustainable agriculture. Its effectiveness in promoting plant growth and controlling
phytopathologies underscores its value in the development of biofertilizer products for organic farming systems.

An experiment was conducted at the Teaching and Research Farm of the Federal University of Technology, Akure, Nigeria to investigate the ability of mycorrhizal fungi, oil palm bunch refuse and sawdust mulches to modulate banana growth and nematode infection. Twenty four suckers of cooking banana cultivar ‘Fougamo’ used for the experiment were collected within the Federal University of Technology, Akure campus. Vegetative growth parameters were measured at termination of experiment while root and rhizome damage was assessed. The mycorrhizal inoculants and the two organic mulches enhanced aerial and subterranean growth. Sawdust mulch increased area of youngest leaf opened by 215%, mycorrhizal fungi by 234% and oilpalm bunch refuse much by 267% respectively. Feeding habit of the three plant parasitic nematode species recovered from the cultivar: Pratylenchus coffeae, Radopholus similis and Helicotylenchus multicinctus was influenced by the type of organic input. Mycorrhizal inoculants ...

The experiment was set up to investigate the relative mycorrhizal dependence of a Falsehorn and a French plantain cultivars with a view to ascertaining the effect on plant parasitic nematodes infection. The experiment was laid out in a completely randomized design, all suckers were pared prior to planting and treatment assigned as either inoculated with the mycorrhizal inoculant or not. At 182 days after planting (DAP), all plants were uprooted and assessed for root and rhizome damage. Plant parasitic nematodes were extracted from both root and soil samples taken from the hole of each plant after uprooting. The results of the study suggests a negative impact of mycorrhizal fungi on the built-up of plant parasitic nematode population on plantain with mycorrhizal inoculation causing a considerable reduction of 37.1% in plant parasitic nematode population density recovered from the roots of False horn plantain compared to just 7.71% reduction recorded for the French plantain genotype. ...

Ralstonia solanacearum is Gram-negative bacterial phyto-pathogens, which cause bacterial wilt disease in several vegetable crops of Solanaceae family. The bacterium is mainly soil and water borne in nature and spread through running water between different agricultural fields. In environment it can survive as VBNC (Viable But Not Culturable) state. Reverse Transcriptase qPCR (RT-qPCR) targeting housekeeping genes is a promising and reliable technique used to detect the VBNC forms of the pathogen. In present investigation three housekeeping genes namely, 16S rRNA, RpoS, and Omp, were evaluated for their specificity. Further to access the viability of the cells 16srDNA (16S rRNA) gene transcript was determined along with pathogenicity test. Strains of R. solanacearum DIBER-117 showed a 20% decrease in 16SrDNA gene transcriptome after 480 days. Among the three sets of primers tested, the primer targeting 16s rDNA is found to have better specificity.

Spodoptera frugiperda is Indonesia’s relatively new invasive polyphagous insect pest. So far, S. frugiperda infestation has only been reported in corn and rice in Indonesia. However, S. frugiperda is known to feed on many commercial crops in other countries. To date, information on the biological parameters of S. frugiperda is limited in Indonesian ecologies. Since host plants are a critical factor for insect life history and have the potential to be used for pest control strategies, it is essential to study the biology and survival of S. frugiperda on different host plants. This research aimed to investigate the survival, development time, and fecundity of S. frugiperda on other host plant species to predict possible infestation rates for use in pest management. The study was conducted by rearing S. frugiperda on 14 common cultivated host plant species in Indonesia. The survival rate, development time, fecundity, and potential attack rate of S. frugiperda on various tested host pla...

The devastating soil-borne pathogen Sclerotium rolfsii has become increasingly significant worldwide, affecting several crops. However, biological disease management, particularly using antagonistic microbes, offers an environmentally friendly alternative to chemical control. Bacillus species, in particular, have demonstrated strong antagonistic potential against various fungal pathogens. In this study, the morpho-microscopic and biochemical characterization of Bacillus isolates obtained from rhizosphere soil was conducted. Furthermore, their antagonistic activities were assessed in vitro using dual culture and well diffusion techniques against S. rolfsii. During primary screening, four isolates viz. S3C9, S1C9, S2C9, and S6C8 strongly suppressed fungal mycelial growth, with inhibition zones measuring 18.3, 14.7, 14.3, and 14.7 mm, respectively. Three isolates (S2C9, S3C9, and S4C9) were further evaluated for inhibitory properties using cell-free supernatant through the well diffusion method, yielding inhibition zones of 6.3, 4.7, and 4.7 mm, respectively. Moreover, molecular analysis identified two isolates, S1C9 and S3C9, as strains of Bacillus subtilis, with GenBank accession codes OP962345 and OQ180051, respectively. This study provides evidence that the local soil of Kot Diji, Sindh Province, Pakistan, harbors beneficial microbes with significant antifungal activity, which could be utilized for future biocontrol strategies against phytopathogenic fungi.

Fifty isolates of dry root rot pathogen Rhizoctonia bataticola collected from different agro-climatic zones in India were evaluated for the degree of subdivision in isolates level. The isolates showed variability in pathogenicity test. Genetic characteristics were analyzed based on the sequence of the rDNA-internal transcribed spacer (ITS) region. The phylogenetic tree based on rDNA-ITS analysis showed that the maximum number of R. bataticola isolates were very diverse and did not depend on geographical origin. Both pathological and molecular data correlated each other and supported that the R. bataticola present in India were very diverse and independent to their origin.

Plant growth-promoting rhizobacteria (PGPR) have significant potential for enhancing soil quality and plant growth; however, their agricultural application is limited by challenges such as immobilization and desiccation vulnerability. Background: This study addressed PGPR solid formulation by applying JetCutter-assisted immobilization technology to PGPR strains isolated from the rhizosphere of hazelnut (Corylus avellana). Methods: Four immobilized PGPR strains were evaluated under controlled greenhouse conditions: Serratia proteamaculans, Pseudomonas mohnii, Pseudomonas baetica, and Bacillus safensis. Their effects on root development, gas exchange parameters, dissolved organic carbon (DOC), and soil enzymatic activities (phosphatase, urease, protease, and β-glucosidase) were assessed. Principal component analysis (PCA) was used to identify the top-performing strain. Results: Treatment with encapsulated bacteria resulted in a 27% increase in DOC compared to controls (p < 0.05), while phosphatase and urease activities increased by 35% and 28%, respectively. Root length and volume improved by 18% and 22%, respectively, with PCA identifying P. baetica as the most effective strain. Conclusions: Immobilized Gram-negative PGPR strains enhanced root development and soil biochemical activity in hazelnuts, whereas B. safensis enhanced photosynthesis but had minimal impact on soil properties. These results highlight functional differences and support the use of PGPR immobilization to promote early plant establishment.

The "oil stain disease" has become a phytosanitary status that involves economic losses for farmers who produce gulupa (Passiflora edulis Sims). For this reason, this research aimed to evaluate the biocontrol activity of Bacillus subtilis ATCC 55033 in a culture medium based on fermented millet as a biocontrol product of the disease. Initially, metabolite production of seven strains of B. subtilis and a reference strain B.s (ATCC 55033) was evaluated; in addition, the in vitro antagonistic ability was evaluated against Xanthomonas axonopodis. Two experiments were performed under in vitro conditions: (1) study of the presence of halos of hemolysis due to metabolite production; (2) analysis of the antagonistic ability by using double layer. It was observed that concerning the average, a number five times bigger of halos of hemolysis and 10 times bigger halos of inhibition in vitro on the growth of X. axonopodis in the strains B.s (ATCC 55033) and B.s TB2 over other strains. Subsequently, the evaluation was performed under greenhouse conditions, based on a randomized block design, in which two treatments were applied over the soil: (1) application of the fermented medium based on millet with B.s ATCC 55033, 24 h before X.a inoculation; (2) application of 5 d post-inoculation. It was observed that the treatment, previous infective process, obtained an average percentage of severity equal to 42.044%. In addition, after the evaluation month, a foliage restoration was presented. In conclusion, it is suggested that these products could act as inducers in the plant systemic resistance to trigger defense responses to infection of X.a.

Plant growth-promoting rhizobacteria (PGPR) have significant potential for enhancing soil quality and plant growth; however, their agricultural application is limited by challenges such as immobilization and desiccation vulnerability. Background: This study addressed PGPR solid formulation by applying JetCutter-assisted immobilization technology to PGPR strains isolated from the rhizosphere of hazelnut (Corylus avellana). Methods: Four immobilized PGPR strains were evaluated under controlled greenhouse conditions: Serratia proteamaculans, Pseudomonas mohnii, Pseudomonas baetica, and Bacillus safensis. Their effects on root development, gas exchange parameters, dissolved organic carbon (DOC), and soil enzymatic activities (phosphatase, urease, protease, and β-glucosidase) were assessed. Principal component analysis (PCA) was used to identify the top-performing strain. Results: Treatment with encapsulated bacteria resulted in a 27% increase in DOC compared to controls (p < 0.05), while phosphatase and urease activities increased by 35% and 28%, respectively. Root length and volume improved by 18% and 22%, respectively, with PCA identifying P. baetica as the most effective strain. Conclusions: Immobilized Gram-negative PGPR strains enhanced root development and soil biochemical activity in hazelnuts, whereas B. safensis enhanced photosynthesis but had minimal impact on soil properties. These results highlight functional differences and support the use of PGPR immobilization to promote early plant establishment.

The "oil stain disease" has become a phytosanitary status that involves economic losses for farmers who produce gulupa (Passiflora edulis Sims). For this reason, this research aimed to evaluate the biocontrol activity of Bacillus subtilis ATCC 55033 in a culture medium based on fermented millet as a biocontrol product of the disease. Initially, metabolite production of seven strains of B. subtilis and a reference strain B.s (ATCC 55033) was evaluated; in addition, the in vitro antagonistic ability was evaluated against Xanthomonas axonopodis. Two experiments were performed under in vitro conditions: (1) study of the presence of halos of hemolysis due to metabolite production; (2) analysis of the antagonistic ability by using double layer. It was observed that concerning the average, a number five times bigger of halos of hemolysis and 10 times bigger halos of inhibition in vitro on the growth of X. axonopodis in the strains B.s (ATCC 55033) and B.s TB2 over other strains. Subsequently, the evaluation was performed under greenhouse conditions, based on a randomized block design, in which two treatments were applied over the soil: (1) application of the fermented medium based on millet with B.s ATCC 55033, 24 h before X.a inoculation; (2) application of 5 d post-inoculation. It was observed that the treatment, previous infective process, obtained an average percentage of severity equal to 42.044%. In addition, after the evaluation month, a foliage restoration was presented. In conclusion, it is suggested that these products could act as inducers in the plant systemic resistance to trigger defense responses to infection of X.a.

It is estimated that diseases, insects and weeds together annually interfere with the production and destroy 36.5% crop production. In general losses of crops due to disease amount to 25% of world crop production per annum (Lugtenberg, 2015). Biological disease control is an attractive strategy for the control of plant diseases. Meanwhile, it also provides practices compatible with the goal of a sustainable agricultural system. Biological control is the suppression of disease by the application of a Biocontrol Agent (BCA) usually a fungus, bacterium, or virus. Weindling (1932) reported the parasitic nature of Trichoderma lignorum on several plant pathogens. Biological disease control is an attractive alternative strategy for the control of plant diseases. Meanwhile, it also provides practices compatible with the goal of a sustainable agricultural system. Insofar as we know, the mechanisms of bio-control may involve and be divided into (i) antibiosis, (ii) competition, (iii) mycopara...

The objective of our study was the antifungal power test of the pomegranate peel aqueous extract PPE, on a phytopathogenic fungal strain of tomato "Fusarium oxysporum f.sp.radicis-lycopersici". For this purpose, a test was carried out, by the direct contact method in PDA potato dextrose agar medium, on the phytopathogen, in different concentrations of PPE (1%, 2%, 3%, 5%). Antifungal activity was evaluated by the estimation of the mycelial growth, the mycelial inhibition rate and the spore count. Our results showed a remarkable and highly significant antifungal activity against the studied phytopathogen, an inhibition index of 100% with the 3% and 5% concentrations was noted. The effectiveness of PPE could be the subject of investigation and exploitation in the integrated control of the tested fungus that causes much damage to the tomato crop.

Mushroom is characterized by having white sporophore, large sized fruiting bodies and delicious flavor. The temperature tolerance has been found to be high, with moderate protein content and good biological efficiency with long shelf life. There is mathematical model to describe mycelia growth on effect of temperature. The maximum mycelial growth rate (1.12 cm/day) at 30°C was observed in the strain Cl-7 at 8.0 pH level.

Rice is a staple crop for a large part of the world population including Vietnam. Although its export is ranged of second place over the world just after Thailand, rice production in Vietnam is challenging by various issues. The most significant is application of agrochemicals, which are not eco-friendly, leading to side effects on the ecosystem and human health. Endophytic bacteria (EB) possess different beneficial traits such as Plant Growth Promoting (PGP) and antagonistic activities against plant pathogens. In this study, a collection of 150 EB strains have been isolated from upland rice roots grown on the mountain-farm in the Tung village, Nam Co commune, Mu Cang Chai district, Yen Bai province, Vietnam. 119/150 isolates showed siderophoreproduction ability including 12 isolates showed the halo orange zone surrounding colonies of 1 – 10 mm in diameter (Dh), considering them as low level of siderophore production, 80 strains exhibited the moderate activity, Dh of 11 – ...

Objective: Study the diversity of cultivable rhizospheric bacteria associated to Agave americana, and select native strains with potential as plant growth-promoting bacteria (PGPB). Design/methodology/approach: The isolated bacteria were phenotypically characterized. The genetic diversity and identity of the strains were revealed by genomic fingerprints and by sequencing of 16S rRNA gene. Plant growth promoting ability and plant inoculation assays were evaluated to know the potential as PGPB. Results: A total of 235 strains were isolated from A. americana rhizosphere and were classified within of 10 different bacterial genera. Rhizobium, Pseudomonas, Acinetobacter had high potential as PGPB. Study limitations/implications Cultivable approach was used to study rhizobacteria. A metagenomic study could expand the knowledge about the structure and diversity of bacterial community associated to A. americana. Findings/conclusions Rhizosphere bacteria have potential use as biofertilizer fo...

Over time plants developed complex mechanisms in order to adapt themselves to the environment. Plant innate immunity is one of the most important mechanisms for the environmental adaptation. A myriad of secondary metabolites with nutraceutical features are produced by the plant immune system in order to get adaptation to new environments that provoke stress (stressors). Hormesis is a phenomenon by which a stressor (i.e., toxins, herbicides, etc.) stimulates the cellular stress response, including secondary metabolites production, in order to help organisms to establish adaptive responses. Hormetins of biotic origin (i.e., biostimulants or biological control compounds), in certain doses might enhance plant performance, however, in excessive doses they are commonly deleterious. Biostimulants or biological control compounds of biotic origin are called &quot;elicitors&quot; that have widely been studied as inducers of plant tolerance to biotic and abiotic stresses. The plant response to...

Pathogen-host interactions involve competition, synergistic or cooperation and coexistence interactions. Host plant can also regulate niche battle among pathogens by defense response which target one or more pathogens either actively or passively. However, in general, virulent pathogens overcome the host defense strategies to infect it. Plant-pathogen interactions are mainly focused on single host-single disease model of infection. However, microbes occur in complex communities in nature and plant infections generally include more than one genotypes and show complexities which cannot be explained by single host-single disease model. Here, we discuss recent understandings about the host-multi-pathogen interactions and their effects on host resistance as well as susceptibility. Here we highlight the recent insights on co-infection systems and identify their future implications in plant disease epidemiology and management.

Diagnosis Techniques and molecular research revolutionize clinical microbiology by providing more sensitive, rapid, and specific approaches to pathogens. Traditional methods rely on phenotypic expression and biochemical products that are gradually being replaced by molecular techniques, including Polymerase Chain Reaction (PCR), which are emerging as the tool of early detection. PCR's development from single-round PCR to real-time PCR has greatly enhanced the efficiency, sensitivity, and cost-effectiveness of molecular diagnostics. Molecular methods are now integral in viral, bacterial, parasitic, and fungal infection diagnosis, as well as in viral load monitoring and resistance testing in virology and bacteriology. PCR allows for viruses rapid detection such as HIV, HCV, and CMV to improve patient outcomes by guiding timely interventions and monitoring treatment effectiveness. Moreover, molecular diagnostics provide reliable identification of fastidious bacteria and antibiotic resistance detection to address challenges that traditional culture methods face in bacteriology. Furthermore, broad-range PCR use has broadened applications in identifying previously undetected pathogens, although PCR-based genotyping is transforming the detection of infections like HPV and bacterial resistance. Molecular diagnostics in public health offer precise pathogen identification and enable efficient disease response. For instance, limitations including the inability to distinguish viable pathogens from non-viable nucleic acids and the need for standardization in molecular tests remain with its advancements. The future of molecular diagnostics lies in the new technologies integration including microarrays and automation, which will further streamline the diagnostic process while reducing costs.

The fall armyworm is a polyphagous lepidopteran pest that primarily feeds on valuable global crops like maize. Insecticides and transgenic crops have long been a primary option for fall armyworm control, despite growing concerns about transgenic crop resistance inheritance and the rate of insecticide resistance development. Global dissemination of the pest species has highlighted the need for more sustainable approaches to managing overwhelming populations both in their native range and newly introduced regions. As such, integrated pest management programs require more information on natural enemies of the species to make informed planning choices. In this study, we present a cost analysis of the production of three biocontrol agents of the fall armyworm over a year. This model is malleable and aimed towards small-scale growers who might benefit more from an augmentative release of natural enemies than a repetitive use of insecticides, especially since, though the benefits of using ...

A total of 22 chickpea dry root rot causing pathogen Rhizoctonia bataticola isolates and 40 antagonistic endophytic bacteria were isolated from chickpea roots which are collected from different chickpea growing districts of Andhra Pradesh. Cultural and morphological variability among the pathogen isolates were studied by growing on PDA and observed variation in colony growth rate , colour, texture, time taken to grow full plate, Sclerotial initiation, Sclerotial density, Sclerotial size and shape. Among the 14 potential endophytic bacterial isolates, Gram negative (7) and Gram positive (7) were recorded in equal proportion and all were rod shaped bacteria. Out of the 14 isolates, a total of 9,

Species of genus Trichoderma may benefit as plant pathogen control agent (mycofungicide) and plant growth promoter (biofertilizer) and their application may lower the production costs and environmental impact. Direct effects of these fungi on plant growth and development are crucially important for agricultural uses and for understanding the roles of Trichoderma in natural and managed ecosystems. The Trichoderma potential as bioagent is utilized through the commercial production of Trichoderma-based product. Commercial products of Trichoderma-based biofungicides account for about 60% of the biofungicide market, while the availability and dispersion of Trichoderma-based biofertilizers are more widespread than commonly known with a tendency to expand due to the easier registrations. Limiting factors for availability of commercial products are expensiveness of registration requirements as they must be registered as pesticides, especially patenting, efficacy testing, toxicological, and biosafety testing. This chapter intends to give insight into agricultural importance of Trichoderma and current status of implementation of Trichoderma products in developing and in the developed countries.

The postharvest rot fungus, Lasiodiplodia theobromae, poses a significant threat to the avocado trade in Ghana as it discounts both the quality and shelf life of freshly harvested avocado fruits. This study evaluated the biological effect of three bioagents, garlic, baking soda, and black pepper, on mitigating postharvest rots of avocado fruits caused by L. theobromae. Isolates of L. theobromae obtained from spoiled fruits were identified using morphological, molecular, and pathogenicity procedures. Eight isolates of L. theobromae were similar in morphology and pathogenicity and genetic markers (ITS). The three bioagents, garlic and pepper seed powder, and baking soda, were evaluated in vitro using the food poison technique at two concentrations, 10 g and 20 g per 100 ml of water. Garlic at 20 g/100 ml of water completely inhibited mycelium growth, followed with 10 g/l (7.8%), and baking soda at 20 g/l (32.6%). Further studies of these bioagents on fruit are recommended.

The effects of oxygen limitation, low redox potential, and high NaCl stress for 7 d in vitro on the rifampicin-resistant biocontrol inoculant Pseudomonas fluorescens CHAORif and its subsequent persistence in natural soil for 54 d were investigated. Throughout the experiment, the strain was monitored using total cell counts (immunofluorescence microscopy), Kogure&#39;s direct viable counts and colony counts (on rifampicin-containing plates). Under in vitro conditions, viable but non-culturable (VBNC) cells of CHAO-Rif were obtained when the strain was exposed to a combination of low redox potential (230 mV) and oxygen limitation. This mimicks a situation observed in the field, where VBNC cells of the strain were found in the water-logged soil layer above the plow pan. Here, VBNC cells were also observed in vitro when CHAO-Rif was subjected to high NaCl levels (i.e. NaCl at 1.5 M but not 0.7 M). In all treatments, cell numbers remained close to inoculum level for the first 12 d after ...

Pseudomonas inoculants may lose colony-forming ability in soil, but soil properties involved are poorly documented. Here, we tested the hypothesis that soil acidity could reduce persistence and cell culturability of Pseudomonas protegens CHA0. At 1 week in vitro, strain CHA0 was found as culturable cells at pH 7, whereas most cells at pH 4 and all cells at pH 3 were noncultured. In 21 natural soils of contrasted pH, cell culturability loss of P. protegens CHA0 took place in all six very acidic soils (pH < 5.0) and in three of five acidic soils (5.0 < pH < 6.5), whereas it was negligible in the neutral and alkaline soils at 2 weeks and 2 months. No correlation was found between total cell counts of P. protegens CHA0 and soil composition data, whereas colony counts of the strain correlated with soil pH. Maintenance of cell culturability in soils coincided with a reduction in inoculant cell size. Some of the noncultured CHA0 cells were nutrient responsive in Kogure's viability test, both in vitro and in soil. Thus, this shows for the first time that the sole intrinsic soil composition factor triggering cell culturability loss in P. protegens CHA0 is soil acidity.

Plant diseases pose a serious threat to human well-being because they harm plants that are essential for environmental stability, economic viability and food security. There are two main issues with Ethiopian faba bean output includes faba bean gall and chocolate spot. Have resulted in significant yield loss. This review focuses on the significance, epidemiology, and treatment of these two diseases. The newly discovered Physoderma viciae causes faba bean gall disease, which is spreading quickly, whereas Botrytis fabae causes chocolate spots. Persistent problem. Efficient management of both diseases requires a comprehensive understanding of their epidemiology, which is associated with environmental factors, host susceptibility, and disease cycles. Crop residue management, crop rotation, the employ resistant varieties, bioagents, compost teas, and chemical fungicides. Are among the management techniques covered. Furthermore, the burden of disease has been reduced by IPM approaches, like as biological control, foliar spraying, and irrigation. Case studies in the South Gondar zone of northwest Ethiopia Bayleton and other fungicides have been shown to effectively suppress faba bean gall. when used in conjunction with varied cropping systems and late sowing. To control these faba bean illnesses and increase yields, it is imperative to implement an integrated disease management strategy that incorporates cultural, biological, and chemical techniques. To create sustainable strategies for controlling these illnesses and preserving Ethiopia's faba bean output, further studies and awareness are needed.

Plant health is essential for food security, and constitutes a major predictor to safe and sustainable food systems. Over 40% of the global crops&#39; productions are lost to pests, insects, diseases, and weeds, while the routinely used chemical-based pesticides to manage the menace also have detrimental effects on the microbial communities and ecosystem functioning. The rhizosphere serves as the microbial seed bank where microorganisms transform organic and inorganic substances in the rhizosphere into accessible plant nutrients as plants harbor diverse microorganisms such as fungi, bacteria, nematodes, viruses, and protists among others. Although, the pathogenic microbes initiate diseases by infiltrating the protective microbial barrier and plants&#39; natural defense systems in the rhizosphere. Whereas, the process is often circumvented by the beneficial microorganisms which antagonize the pathogens to instill disease resistance. The management of plant health through approaches f...

Finger millet (Eleusine coracana) is one of the major staple food in India. the crop yield and its quality is affected by numerous factors including pre and post-harvest pathogens, poor storage conditions, improper irrigation practices and others. Among different phytopathogens which attack the Pyricularia grisea affects major yield loss in finger millet and many researchers developed potential management strategies to combat against target pathogen. This review deals with the overall information available for the utilization of bio-agents, against blast pathogen. Various researchers reported utilization of bio-agents is an effective management strategy against blast pathogen also economical and environmentally safe. In this review we made an attempt to present detailed overview potential utilization of bio-agents in supressing Pyricularia grisea.

Alternaria leaf spot can be a devastating disease as the mechanism by which the fungus Alternaria brassicae (Berk.) Sacc. spread in canola is not yet fully understood. It is essential to understand the infection process and mechanisms of resistance by studying biotic and abiotic factors. In the present study, two abiotic elicitors-Salicylic acid (200 ppm), and Milor MZ (Mancozeb 64% + Metalaxyl 8% WP) fungicide (100 ppm) along with the biotic elicitor Pseudomonas fluorescens (PF83), were examined to induce systemic resistance in Brassica napus AACC (2n=38) and Raphanus brassica AARR (2n=38) against Alternaria leaf spot disease. The histological study revealed that R. brassica exhibited resistance to Alternaria leaf spot disease. Fungal colonies were observed on R. brassica leaves at 120 hours post-inoculation (hpi), and Similar observations were seen on B. napus leaves after 24 hpi. However, signs of the pathogen, including hyphae, conidia, appresoria, and dead cells, were present on the surface of the infected leaf in both genotypes but were not observed in plants treated with biotic and abiotic elicitors. Thus, the biotic elicitors PF83 and the abiotic elicitors SA and Milor MZ significantly reduced (P≤0.5) lesion sizes of pathogen at 24, 84, and 120 hpi in both genotypes. Finally, the results suggested that R. brassica produced resistance to Alternaria leaf spot. Additionally, the application of PF83 isolate is considered a useful tool for enhancing protection methods for canola genotypes.

This research was conducted to ascertain the coliform resident in the rumen of slaughtered cow. Two samples were aseptically collected and processed. Tenfold serial dilution was done and 102, 104 and 106 diluents were spread plated on Maconkey and Eosin methylene blue agar. After 24hrs of incubation at 37 0C, (4.0×10 4 , 3.0 ×10 6 , 3.0 ×10 8 ;) (6.0×10 4 ; 9.0×10⁶, 9.0×10 8)cfu/ml were recorded for Maconkey for sample 1 &2 respectively. Also (2.0×10 4 8.0×10 6 3.0×10 8;),(3.0 ×107, 9.0×10 7 , 9.0×10 7) cfu/ml was counted for Eosin methylene blue for samples 1 & 2 respectively. After isolation and identification, Escherichia coli, Klebsiella pneumonia, Enterobacter spp and Citrobacter sp were identified as possible organisms. Of the possible organisms, Escherichia coli and Citrobacter sp were predominant. Further visit to the ranch revealed that several negative factors were responsible for the presence of the pathogenic organisms. These factors are to be corrected and consumers are advised to cook the meat very well before eating.

M odern agriculture is largely based on dense cropping and heavy application of pesticides and fertilizers, resulting in very serious issues such as soil pollution and land degradation. Therefore, it is necessary to develop alternative and greener strategies to combat pests and pathogens towards sustainable agriculture and environment. There are large number of microorganisms in nature, soil, capable of suppress crop pathogen, diseases and pests. In addition, accumulating reports uncovered the beneficial microbes for crop growth promotion, including phosphate or potassium solubilization and nitrogen fixation. The beneficial traits of microorganisms can be harnessed and utilized as alternative strategies to fertilize crops or reduce crop disease and pests. Over the years, we have been isolating, characterizing and applying beneficial microorganisms as biopesticides, biofertilizers or bioproduct factories. These include Paenibacillus polymyxa CR1, Burkholderia cenocepacia CR318, Bacillus velezensis 9D-6, Arthrobacter sp. LS16 and Acinetobacter calcoaceticus CA16. We are also carrying out complete bacterial genome sequencing to further characterize the genetics and regulatory pathways for the beneficial traits of the isolated bacteria. Here, we will summarize our research and latest discovery in develop biopesticides and biofertilizers, and discussing their potential application in reducing chemical fertilizers and pesticides, towards more sustainable agriculture and environment.

Both biotic and abiotic stresses are major constrains to agricultural production. Under stress conditions, plant growth is affected by a number of factors such as hormonal and nutritional imbalance, ion toxicity, physiological disorders and susceptibility to disease. Plant growth under stress conditions may be enhanced by the application of microbial inoculation including PGPR. These microbes can promote plant growth by regulating nutritional and hormonal balance, producing plant growth regulators and solubilizing nutrients. In addition to their interactions with plants, these microbes also show synergistic interactions with other microbes in the soil environment. These interactions may be vital for sustainable agriculture because they mainly depend on biological process rather than on agrochemicals to maintain plant growth and development as well as proper health under stress conditions. Biological interactions of PGPR with soil microbes are believed to cause a cumulative effect on...

The bacterial wilt disease caused by Ralstonia pseudosolanacearum presents a notable economic risk to a variety of crucial crops worldwide. During preliminary isolation of this phytopathogen, several colonies of other saprophytic bacteria may be mistaken with it. So, the present study aims to address this issue by proposing the application of immunogenic proteins, particularly flagellin (FliC), to enable a rapid and early identification of bacterial wilt. In this study, a novel approach is unveiled for the early detection of R. pseudosolanacearum. The study exploits the immunogenic attributes of flagellin (FliC), by generating polyclonal antibodies against recombinant FliC within model organisms—rabbits and mice. The efficacy of these antibodies is meticulously assessed through discerning techniques, including DAS-ELISA and Western blot analyses, which elucidate their remarkable specificity in identifying various R. pseudosolanacearum strains. Furthermore, the introduction of antibody-coated latex agglutinating reagents offers an additional layer of confirmation, substantiating the feasibility of establishing a laboratory-based toolkit for swift screening and unambiguous identification of the bacterial wilt pathogen. This study presents a significant stride toward enhancing early diagnostic capabilities, potentially revolutionizing agricultural practices by safeguarding crop yield and quality through proactive pathogen detection and mitigation strategies

Organic fertilizers such as compost, compost tea and seaweed extracts (Algean) combined with benzo (1,2,3) thiadiazole-7-carbothioic acid S-methyl ester (BTH)) showed significant effect on the powdery mildew-infected cucumber leaves with Sphaerotheca fuliginea. We have shown that spraying the infected cucumber leaves with the BTH (0.05 mM) combined with the organic fertilizers strongly decreased the disease severity of the cucumber powdery mildew fungus from 85.1% to 3.4% as compared to the control leaves which infected only with the pathogen. Furthermore, organic fertilizers combined with BTH increased significantly vegetative growth characters of cucumber (stem length, number of leaves /plant, leaf area /plant and chlorophyll content) especially at the earlier stage of growth as compared to the control plants (chemical fertilizer only). Also, most of the organic materials produced the highest cucumber early yield and fruit quality, but total yield was equal or less than the chemical fertilizers. Interestingly enough, that organic fertilizers combined with BTH elevated the ascorbic acid content (chemical quality of cucumber fruits) and decreased the nitrate content which very harmful as well as increased the fruit yields as compared to the control plants.

Petunia is one of the most popular ornamental plants used in containers, hanging baskets, wall decoration, borders, as a seasonal ground cover in the garden due to its various flower colours and patterns and has an important commercial value. However, it shows high sensitivity to drought stress. The present study was conducted to determine the effects of mycorrhizae and rhizobacteria applications against drought stress in Petunia hybrida 'Super Cascade White'. For drought stress, restricted irrigation was applied to the plants at the rates of 100%, 75%, 50% and 25%. In a result of the research, as the amount of water stress increased, there was a negative effect on all parameters (plant height, number of leaves, number of flowers, petal length, petal width, plant fresh and dry weight, root fresh and dry weight, root length) examined. Applying mycorrhizae and rhizobacteria separately or in combination reduced this negative effect. It was concluded that mycorrhizae+rhizobacteria (plant and root fresh/dry weights, root length) treatments for underground parts; separate applications of rhizobacteria (leaf, flower number and petal length) and mycorrhizae (plant height, petal width) treatments for aboveground parts are the most effective applications. When it comes to water stress, we found that a 75% water restriction treatment gives the best results on petunia morphological traits after control plants treated with 100% water. In this respect, the application of microbial biostimulants with 25% less water is sufficient for resistance to abiotic stress conditions in petunias.

Tomato plants treated with P. fluorescens as seed treatment @ (10ml /kg of seed) plus Allium sativum as foliar spray @ (15% at 30 & 45 DAT) and challenge inoculated with A. solani showed induction of earlier and increased level of defense enzymes viz., PO, PPO, PAL and catalase as well as PR proteins chitinases and -1, 3 glucanases. In field trial, the treatment T7 with application of P. fluorescens as seed treatment @ (10ml/kg of seed) plus Allium sativum as foliar spray @ (15% at 30 & 45DAT) increased the fruit yield.