Management Of Fungal Diseases Research Articles

Efficacy of native fluorescent Pseudomonads against soil-borne phytopathogenic fungi

The present investigation was carried out to evaluate the antagonistic potential of fluorescent Pseudomonads isolated from different crop rhizospheres of zone III A and Zone II of Bihar against three soil-borne fungal phytopathogens viz., Rhizoctonia solani, Sclerotium rolfsii and Fusarium oxysporum using dual culture technique. Sixteen fluorescent Pseudomonads were isolated from different crop rhizospheric soils collected from different locations of Bhagalpur and kishanganj district. In vitro evaluation results indicated the significant differences among the fluorescent Pseudomonads in their efficacy against the test fungi. Among the sixteen fluorescent Pseudomonads tested, isolate BMGh shown maximum antagonism against Rhizoctonia solani with 55.66 per cent inhibition of pathogen over control followed by isolate whkh (47.16 per cent) and Msksn (46.22 per cent). Isolate CHGH was found least effective (15.09 per cent inhibition). Against Sclerotium rolfsii, isolate LnsB had maximum antagonism potential with 88.81 per cent inhibition of radial growth of the fungus followed by whkh (79.72 per cent inhibition) and isolate BRKH was found least effective (23.78 per cent) followed by CKSB (32.87 per cent). Isolates MZksn and BRGh were found to have maximum antagonistic potential against Fusarium oxysporum (58.74 per cent) followed by WHSB (56.65 per cent). The isolate MRKH was found least effective (15.39 per cent) followed by MSKSN (20.29 per cent). The effective fluorescent Pseudomonad isolates screened under in vitro may further used for effective management of soil-borne fungal plant diseases in integrated disease management strategies and in organic farming system.

Egy Aspergillus niger törzs fermentlevének lehetséges felhasználása a szőlő gombás betegségeinek megelőzésére

The present study was aimed to examine the use of culture filtrates of defensin-producing fungal strains against the most important fungal and pseudofungal infections of grapevine as an environmentally sound alternative of chemical control. Twenty-seven isolates of five defensin-producing fungal species were tested for antifungal activity. Four isolates (one Aspergillus giganteus and three Aspergillus niger) decreased the viability of the test organism successfully. The isolate with the highest antifungal efficacy (Aspergillus niger SZMC2759) was subjected to detailed investigation. The culture filtrate of the strain was effective against epicuticular mycelia and conidia of Botrytis cinerea, Guignardia bidwellii and Erysiphe necator, but not against subcuticular mycelia and Plasmopara viticola cells. The culture filtrate also prevented the development of powdery mildew symptoms on grapevine cuttings. Several modes of action were detected: inhibition of germination, membrane permeabilization, plasmolysis, fragmentation of nuclei. Certain parameters (pH, stress, aeration) of the fermentation were optimized for the highest antifungal activity. According to the results, culture filtrate of Aspergillus niger can be a promising agent in the management of fungal diseases of grapevine.

Baseline sensitivity of Corynespora cassiicola to metconazole and efficacy of this fungicide

Triazole fungicides with broad spectra constitute the standard strategy for the management of fungal diseases of cucumber. In this study, the in vitro activities of metconazole were tested based on mycelial growth using 121 Corynespora cassiicola isolates. The distribution of EC50 values of metconazole for 121 isolates was a unimodal curve with a mean of 0.78 ± 0.41 μg mL−1. Cross-sensitivity data indicated that sensitivity to metconazole did not correlate with sensitivity to difenoconazole, tebuconazole, myclobutanil or hexaconazole (P > 0.05). The relative treatment effect values shown by in vivo assays with detached cucumber leaves and potted seedlings indicated that the protective and curative effects of metconazole were higher than those of difenoconazole. Field data suggested that the application of metconazole at 150 g a.i. ha−1 markedly reduced the disease severity and disease incidence of Corynespora leaf spot compared with the effects obtained with difenoconazole treatment, with relative treatment effects of 0.24 and 0.17 for 2017 and 2018, respectively. These findings demonstrate that metconazole could play a vital role in the integrated management of cucumber Corynespora leaf spot.

Antimicrobial activities of Tephrosia vogelii against selected pathogenic fungi and bacteria strains

ABSTRACTCandida albicans and Cryptococcus neoformans are dangerous pathogens causing fungal diseases. C. albicans and C. neoformans developed resistance to fungicides such as fluconazole. Similarly, pathogenic bacteria Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Salmonella typhi have become resistant to antibiotcs such as methicillin. Thus, searching for alternative antimicrobial agents is inevitable. Tephrosia vogelii used traditionally for management of fungal and bacterial diseases is potential source of antimicrobial agents. It is in this vein that, antimicrobial activities of leaf and root extracts of T. vogelii were evaluated against C. albicans (ATCC 90028), C. neoformans (clinical isolate), S. aureus (ATCC25923), E. coli (ATCC29953), K. pneumoniae (ATCC 700603) and S. typhi (NCTC 8385). A two-fold serial dilution method using the sterilised 96 wells of polystyrene microlitre plates used to determine the minimum inhibitory concentration (MIC) of extracts. Hexane and dichloromethane extracts exhibited the lowest activity against fungi strains with MICs >10 mg/mL. Root and leaf methanolic extracts exhibited activity at MICs of 5 and 1.25 mg/mL, respectively, against both tested fungi. Dichloromethane and methanolic extracts exhibited antibacterial activity with MICs ranging from 2.5 - 10 mg/mL and 0.625 - 5 mg/mL, respectively. Antimicrobial activities of the extracts of T. vogelii revealed potentiality of bioactives against fungal and bacterial diseases.

Candida auris: what have we learned so far?

The increasing prevalence of fungal infections due to Candida species has been well described in critically ill patient populations, but in recent years a new species, Candida auris has received attention from the medical community worldwide. We aim to summarize the current knowledge related to C. auris, as new identification techniques, novel antifungal agents and more experience with outbreak management have been published in the past few years. C. auris has been described in several countries, arising independently in separate clades. Its resistance to multiple antifungals and persistent colonization of patients and medical surfaces have become a therapeutic and infection control challenge. Recent elucidation of some of the molecular mechanisms related to pathogenicity and studies of in-vitro efficacy of novel antifungal agents can better guide therapy. As C. auris continues to cause outbreaks worldwide, newer, and more efficient identification techniques, novel antifungals, and more knowledge in effective infection control techniques will allow better clinical outcomes in the management and control of invasive fungal disease.

A positive BAL galactomannan in non-haemato-oncology patients risks harmful overtreatment.

Introduction. Evidence for the clinical utility of bronchoalveolar lavage (BAL) galactomannan in the management of fungal disease outside of haemato-oncology patients is limited.Aim. To determine how the introduction of BAL galactomannan testing impacted on the diagnosis and management of invasive aspergillosis and other fungal diseases in non-haemato-oncology patients.Methodology. Retrospective review of all adult patients (age ≥16 years) without a diagnosis of haematological malignancy who had a positive BAL galactomannan from 1 November 2014 to 30 April 2018. Using electronic patient records we obtained demographic data, clinical details, laboratory investigations, relevant radiology and antimicrobial history for each case.Results. In total, 121 episodes with a galactomannan OD index of ≥0.500 were included in the study; 29 cases (24 %) were felt to reflect fungal disease. Antifungal therapy was commenced as a direct consequence of a positive BAL galactomannan result in 13 patients where the ultimate diagnosis was subsequently considered to be non-mycological: associated medication-related side-effects in this group included deranged liver function tests (n=3), rash (n=1) and fever (n=1), related to amphotericin B (n=1) and voriconazole (n=4).Conclusion. We show that vigilance is required when interpreting galactomannan results in non-haematology patients to avoid potentially harmful overtreatment.

A consensus document for the clinical management of invasive fungal diseases in pediatric patients with hematologic cancer and/or undergoing hematopoietic stem cell transplantation in Brazilian medical centers

In the present paper we summarize the suggestions of a multidisciplinary group including experts in pediatric oncology and infectious diseases who reviewed the medical literature to elaborate a consensus document (CD) for the diagnosis and clinical management of invasive fungal diseases (IFDs) in children with hematologic cancer and those who underwent hematopoietic stem-cell transplantation. All major multicenter studies designed to characterize the epidemiology of IFDs in children with cancer, as well as all randomized clinical trials addressing empirical and targeted antifungal therapy were reviewed. In the absence of randomized clinical trials, the best evidence available to support the recommendations were selected. Algorithms for early diagnosis and best clinical management of IFDs are also presented. This document summarizes practical recommendations that will certainly help pediatricians to best treat their patients suffering of invasive fungal diseases.

Residual dynamics of azoxystrobin and combination formulation of trifloxystrobin 25% + tebuconazole 50%-75 W G on isabgol (Plantago ovata Forssk.) and soil

To elucidate the fate of azoxystrobin and combination formulation of trifloxystrobin and tebuconazole in isabgol ecosystem, a simple and efficient analytical method was developed using QuEChERS (quick, easy, cheap, effective, rugged and safe) extraction method followed by analysis in gas chromatography combined with electron capture and nitrogen-phosphorus detector. The method gave very good overall mean recoveries in the range of 69–91%. The limit of quantification were 65, 25, 40 μg kg−1 for azoxystrobin, trifloxystrobin and tebuconazole in isabgol herbage, respectively. The values for corresponding fungicide in soil were 50, 25 and 25 μg kg−1, for isabgol seed with husk were 80, 50 and 75 μg kg−1, respectively. The results revealed that the dissipation pattern of studied fungicides in the soil and isabgol herbage followed first-order kinetics. The half-life of trifloxystrobin in isabgol herbage were shorter (3.0–3.3 days) than tebuconazole (5.1–5.6 days) and azoxystrobin (5.5–7.7 days). Similarly soil half-lives were also shorter for trifloxystrobin (5.0–6.1 days) as compared to tebuconazole (7.9–8.6 days) and azoxystrobin (8.4–10.0 days). The residues of these fungicides in soil, isabgol herbage and seed with husk at harvest were below the detectable limit which supports the application of these fungicides in the management of fungal diseases in isabgol.

Efficacy of some bio-control agent formulations on scab of cowpea and groundnut late leaf spot in the Nigerian savanna

Field experiment on fungicidal efficacy of Trichoderma harzianum, Pseudomonas fluorescens and Bacillus cereus formulations against cowpea scab and groundnut late leaf spot was conducted. The trials were conducted in 2016 and 2017 rainy seasons on two farms of the Institute for Agricultural Research located at Samaru, Zaria (110 12′ N, 070 37′ E) in the Northern Guinea savanna and Minijbir, Kano (08031' E., l20 03' N) in the Sudan savanna. The formulations were applied as seed treatment, foliar spray and also incorporated into the soil by broadcasting the powdered formulations on the ridges. The experiment was laid in Randomized Complete Block Design replicated three times with five treatments which consisted of the three formulations, Funguforce (Mancozeb + Carbendazim) and control. Data were taken on plant emergence, pod yield, disease incidence and severity. Irrespective of the treatments, incidence of scab at both Samaru and Minjibir were at par. However, Funguforce application gave lowest mean scab severities of 10% and 8.5% at Minjibir and Samaru respectively in 2017. In 2016 at Samaru, P. fluorescens had the lowest incidence (50.57 %) while B. cereus had the lowest severity (14.40 %) of groundnut late leaf spot. At Minjibir however, T. harzianum recorded the lowest incidence (48.75 %) and severity (18.22 %). The incidence and severity of groundnut late leaf spot at Samaru in 2017 did not significantly vary while at Minjibir lowest incidence (9.77 %) and severity (9.73 %) were recorded on Funguforce. The microbial formulations recorded an average pod yield increase of 10 – 58 % which was comparable with that of Funguforce. The use of formulations of T. harzianum, P. fluorescens and B. cereus in the management of fungal diseases of cowpea and groundnut in the Nigerian savanna is therefore recommended.Keywords: Genetic-crosses, RILs, Polymorphisms, Genetic-Markers, EPN

Effect of an intervention to improve the prescription of antifungals in pediatric hematology-oncology.

The use of antifungals has expanded in pediatric hematology-oncology, and the need to develop pediatric-based surveillance and education activities is becoming crucial. The aims of this study were to evaluate the impact of a multidisciplinary protocol on the adequacy of antifungal prescription in a pediatric hematology-oncology unit and to assess the effect of an educational intervention to improve the knowledge of prescribing pediatricians over time. A multidisciplinary team established a protocol for the management of invasive fungal disease (IFD). The use of antifungals before (January 2012-May 2013) and after the protocol (June 2013-December 2015) was evaluated. Prescribing pediatricians attended a training course on IFD and were evaluated before 0, 6, and 12 months after the intervention. During the study period, antifungal agents were used in 185 episodes (56 children, 39.3% females), and were administered as prophylaxis (58.9%), empiric (34.6%), or targeted therapy (6.5%). Antifungal prescriptions were inadequate in 7% of the episodes, related to drug selection (53.8%), dosage (38.5%) and route of administration (7.7%). After protocol implementation, inadequate prescriptions decreased 9.9% (15.2% vs 5.3%; P=.04). Following the educational activity, the percentage of adequate responses to the questionnaire improved significantly compared to baseline, and persisted over time (19.7% improvement at 0 months [P<.0001]; 21.1% at 6 months [P<.0001]; 16.6% at 12 months [P=.002]). The establishment of multidisciplinary protocols and education activities improved the quality of antifungal prescription and the knowledge of prescribers regarding antifungal therapy. Therefore, these activities may be important for the implementation of antifungal stewardship programs in pediatrics.

Potential of Yeasts as Biocontrol Agents of the Phytopathogen Causing Cacao Witches' Broom Disease: Is Microbial Warfare a Solution?

Plant diseases caused by fungal pathogens are responsible for major crop losses worldwide, with a significant socio-economic impact on the life of millions of people who depend on agriculture-exclusive economy. This is the case of the Witches’ Broom Disease (WBD) affecting cacao plant and fruit in South and Central America. The severity and extent of this disease is prospected to impact the growing global chocolate market in a few decades. WBD is caused by the basidiomycete fungus Moniliophthora perniciosa. The methods used to contain the fungus mainly rely on chemical fungicides, such as copper-based compounds or azoles. Not only are these highly ineffective, but also their utilization is increasingly restricted by the cacao industry, in part because it promotes fungal resistance, in part related to consumers’ health concerns and environmental awareness. Therefore, the disease is being currently tentatively controlled through phytosanitary pruning, although the full removal of infected plant material is impossible and the fungus maintains persistent inoculum in the soil, or using an endophytic fungal parasite of Moniliophthora perniciosa which production is not sustainable. The growth of Moniliophthora perniciosa was reported as being antagonized in vitro by some yeasts, which suggests that they could be used as biological control agents, suppressing the fungus multiplication and containing its spread. Concurrently, some yeast-based products are used in the protection of fruits from postharvest fungal spoilage, and the extension of diverse food products shelf-life. These successful applications suggest that yeasts can be regarded a serious alternative also in the pre-harvest management of WBD and other fungal plant diseases. Yeasts’ GRAS (Generally Recognized as Safe) nature adds to their appropriateness for field application, not raising major ecological concerns as do the present more aggressive approaches. Importantly, mitigating WBD, in a sustainable manner, would predictably have a high socioeconomic impact, contributing to diminish poverty in the cacao-producing rural communities severely affected by the disease. This review discusses the importance/advantages and the challenges that such a strategy would have for WBD containment, and presents the available information on the molecular and cellular mechanisms underlying fungi antagonism by yeasts.

Advances in the Diagnosis and Management of Invasive Fungal Disease

Advances in the Diagnosis and Management of Invasive Fungal Disease

Charlie van der Horst (1952-2019)

Charlie van der Horst, an emeritus professor at the University of North Carolina and a friend of Pathogens and Immunity, disappeared from sight on Friday, June 14 during a marathon swim in the Hudson River. His death was confirmed. Few who knew him would call him Charles as formality was not his strong-suit. Charlie was born in Holland to a Dutch father and a Polish Holocaust survivor mother. His family moved to the Buffalo, New York area and sent Charlie to school at Andover. He attended Duke University where he captained the varsity swim team in 1973-74. He remained a powerful swimmer, competing often in national Masters’ competitions. He received his MD degree from Harvard in 1979 and trained in medicine at Montefiore Medical Center and Infectious Diseases at the University of North Carolina. He was an expert in the management of fungal diseases and when the AIDS epidemic began, he knew he had to commit his career to AIDS research and care. He led a highly successful AIDS Clinical Trials Unit at the University of North Carolina and was a respected leader in this national consortium who gained international recognition and respect for his work. More than most anyone else I know, Charlie was driven to fight for justice, anywhere, any time. At the 2000 IAS meeting in Durban, South Africa he recognized that the greater AIDS need was in the developing world and he redirected his entire career towards the development of research and care programs in Africa. When Ebola hit West Africa, Charlie rushed to Liberia to help. In the U.S., Charlie was on the front lines urging his state legislature to deal fairly with all North Carolinians, working hard to fight for equity in health care. He was beloved by so many, respected for his talents, admired for his decency. He was, as my grandmother would have said—a mentsch—and more. Our world is lucky to have had him and is diminished by his loss.

Comparative genomic analysis of monosporidial and monoteliosporic cultures for unraveling the complexity of molecular pathogenesis of Tilletia indica pathogen of wheat

Tilletia indica (Ti) - a quarantined fungal pathogen of wheat and its pathogenesis is chiefly governed by pathogen effectors secreted inside the host plant. The de novo genome sequencing of several field isolates and stages available could be used for understanding the molecular pathogenesis. The presence of gaps and low coverage of assembled genomes poses a problem in accurate functional annotation of such functions. In the present study attempts were made to improve the Ti draft genome through reconciliation of globally available datasets of three highly virulent monoteliospore cultures of Ti field isolates. It has sequence depth of 107x and N50 scaffold size of 80,772 (more than 26 times as large as achieved in the draft assembly) with highest sequence contiguity, more accurate and nearly complete. Functional annotation revealed that Ti genome contains 9209 genes evolved with many expanded gene families and arranged mostly in a cluster. About 79% of Ti genes were orthologous to other basidiomycetes fungi, Around 7.93% proteins were having secretary signals and 6.66% were identified as highly virulent pathogenicity genes. Using improved Ti genome as a reference, the genomic variation was assessed with respect to repeats, SNPs/InDel, gene families and correct set of virulence associated genes during its life cycle. The comparative intra-species, inter-stage and inter-species genomic variation will have broader implications to understand the gene regulatory networks involved in growth, mating and virulence behaviour of Tilletia f. spp. and also for better appreciation of fungal biology and disease management.

Diagnostic-driven management of invasive fungal disease in hematology in the era of prophylaxis and resistance emergence: Dutch courage?

Patients receiving intensive anti-leukemic treatment or recipients of allogeneic hematopoietic stem cell transplantation (HSCT) are prone to develop invasive fungal disease caused by both Aspergillus and non-Aspergillus moulds. Overall mortality following invasive mould disease (IMD) is high; adequate and timely antifungal treatment seems to ameliorate the outcome, yet early diagnosis in the haematological patient remains a challenge for most clinicians. Prophylaxis and the empiric addition of antifungal therapy to neutropaenic patients with fever persisting or recurring during broad-spectrum antibiotic treatment is therefore standard of care in many institutions. However, aside from the potential for overtreatment and important side effects, the emergence of resistance to medical triazoles in Aspergillus fumigatus poses a risk for inadequate initial treatment. Initial voriconazole therapy in patients with azole-resistant invasive aspergillosis was recently shown to be associated with a 23% increased mortality rate compared to the patients with azole-susceptible infection, despite changing to appropriate antifungal therapy once resistance was detected. Moreover, fever is not always present with IMD; therefore, cases may be missed when relying solely on this symptom for starting diagnostic procedures and antifungal treatment. At our institution, a diagnostic-driven treatment approach for IMD was implemented relying on clinical but also laboratory markers to start antifungal treatment. We describe the basis and clinical implementation of our diagnostic-driven approach in this review.

Management of Invasive Fungal Disease in Neonates and Children.

Invasive fungal diseases (IFD) are an important cause of morbidity and mortality in premature neonates and immunocompromised pediatric patients. Their diagnostic and therapeutic management remains a challenge. A nationwide survey was conducted among 13 of the largest pediatric units in the United Kingdom, to obtain insight in the current management of IFD in neonates and children. All responding centers were tertiary teaching centers. The use of fungal diagnostic tools and imaging modalities varied among centers. Antifungal prophylaxis was prescribed in most centers for extreme-low birth weight (LBW) infants and high-risk hemato-oncologic patients, but with a huge variety in antifungals given. An empirical treatment was favored by most centers in case of febrile neutropenia. First line therapy for candidemia consists of either fluconazole or liposomal amphotericin B, with voriconazole being first-line therapy for invasive aspergillosis. Disseminated invasive aspergillosis was most often mentioned as a reason to prescribe combination antifungal therapy. In conclusion, this survey reinforces the fact that there are still important aspects in the management of pediatric IFD which should ideally be addressed in pediatric clinical trials. Attention needs to be given the knowledge gaps as observed in the results of our survey to optimize the management of IFD in children and neonates.

Detection of Gray Mold Leaf Infections Prior to Visual Symptom Appearance Using a Five-Band Multispectral Sensor.

Fungal leaf diseases cause economically important damage to crop plants. Protective treatments help producers to secure good quality crops. In contrast, curative treatments based on visually detectable symptoms are often riskier and less effective because diseased crop plants may develop disease symptoms too late for curative treatments. Therefore, early disease detection prior symptom development would allow an earlier, and therefore more effective, curative management of fungal diseases. Using a five-lens multispectral imager, spectral reflectance of green, blue, red, near infrared (NIR, 840 nm), and rededge (RE, 720 nm) was recorded in time-course experiments of detached tomato leaves inoculated with the fungus Botrytis cinerea and mock infection solution. Linear regression models demonstrate NIR and RE as the two most informative spectral data sets to differentiate pathogen- and mock-inoculated leaf regions of interest (ROI). Under controlled laboratory conditions, bands collecting NIR and RE irradiance showed a lower reflectance intensity of infected tomato leaf tissue when compared with mock-inoculated leaves. Blue and red channels collected higher intensity values in pathogen- than in mock-inoculated ROIs. The reflectance intensities of the green band were not distinguishable between pathogen- and mock infected ROIs. Predictions of linear regressions indicated that gray mold leaf infections could be identified at the earliest at 9 h post infection (hpi) in the most informative bands NIR and RE. Re-analysis of the imagery taken with NIR and RE band allowed to classify infected tissue.

Mancozeb impaired male fertility in rabbits with trials of glutathione detoxification

The study aims to evaluate the potential reproductive toxicity induced by mancozeb fungicide in male rabbits and to examine the ameliorative effect of glutathione (GSH), a non-enzymatic antioxidant, against mancozeb reproductive toxicity. Mancozeb is a member of the dithiocarbamates group currently in use in the management of fungal diseases of plants. To achieve these aims, mature male White New-Zealand rabbits of 4–5 months old were randomly assigned to four groups of 9 animals each: control, mancozeb only, mancozeb and GSH, and GSH only. This study discovered a significant reduction in serum FSH, LH, testosterone and testicular LDH, ACP, and ALP levels in the groups of mancozeb-treated rabbits compared with control. The mancozeb-treated groups also showed significant losses in sperm viability, along with a significant increase in the number of abnormal sperms. Finally, an upregulation in steroidogenic 3β-HSD enzyme activity was noted in mancozeb-treated rabbits. Histopathological inspection of the testicles established disruption of the germinal epithelium with vacuolization of Leydig cells and reduced spermatogenic cells. GSH co-administration increased serum concentrations of FSH, LH, testosterone, and levels of the testicular enzymes: LDH, ACP, and ALP. Improved steroidogenesis was indicated in this group by a significant improvement in the testicular 3β-HSD enzyme, by a significant increase in sperm viability, and by a significant decrease in the number of abnormal sperms. The findings of this study suggest that mancozeb exposure has anti-spermatogenic and anti-steroidogenic adverse effects in rabbits and administration of GSH may alleviate the reproductive toxicity.

Antifungal Potential of Plant Growth Promoting Bacillus Species Against Blossom Blight of Rose

Blossom blight caused by Botrytis cinerea is one among the most devastating diseases that cause complete post-harvest loss in flower crops. The present study focuses on the development of effective bioformulation towards suppression of blossom blight and plant growth promotion in rose. Bacillus amyloliquefaciens (VB2) and Bacillus subtilis (AP) effectively inhibited mycelial growth of B. cinerea in vitro. Genome screening of VB2 and AP revealed the presence of antimicrobial peptide genes including, ituD, ipa14, bacA, bacD, srfA, sfP, spaC, spaS responsible for the biosynthesis of antibiotics such as iturin, bacilysin, bacillomycin, surfactin and subtilin. Further, the presence of volatile antifungal compounds in the bacterial secretome was identified through gas chromatography–mass spectrometry (GC/MS) analysis. Upon treatment, AP accelerated the metabolite profile of the plants and a rise in peak area of antifungal compounds such as, pentadecanoic acid, n-hexadecanoic acid, octadecanoic acid (stearic acid) and tetradecanoic acid was observed. In vitro, VB2 produced maximum indole acetic acid (9.17 µg/ml) and gibberellic acid (8.20 µg/ml) in nutrient broth. Under field conditions, foliar spray of VB2 at 0.5% (5 ml/l), four times at weekly interval suppressed blossom blight incidence (64% reduction over control) and also promoted yield. Future research towards development of an effective bioformulation with extended shelf life will aid in the management of various fungal, bacterial and viral diseases in different crop plants.

Strategies to address emerging fungal diseases in peony (Paeonia lactiflora) in the United States

The most important step in any effective disease management strategy is proper diagnosis. Therefore, in an effort to assist growers with disease management, herbaceous peony (Paeonia lactiflora) samples were collected and submitted to our lab from 12 states in the United States to determine the range of diseases present in both landscape and commercial settings. Both morphological and molecular techniques were used in the identification of pathogens isolated from peony flowers, leaves, stems, and roots. Trials were conducted to confirm the ability of all pathogens to cause disease on healthy peony tissue. This survey revealed new species-host-state combinations in several states as well as five different fungal genera that had not previously been identified on peonies in the country: a Botryosphaeria sp., up to 3 Colletotrichum spp., Mycocentrospora acerina, a Phoma sp., and Pilidium concavum. Each of these pathogens have only been reported a few times worldwide and there is correspondingly little to no information available on their management. Given the need for growers to address these emerging disease issues, we outline potential management strategies for fungal peony pathogens. Our recommendations take into account general fungal disease management tools, published information on the specific biology of these organisms, observations of peony diseases over our years of fieldwork, and examples from other pathosystems that have been successful in managing diseases caused by the pathogens we have found on peonies.