Disease In Nursery Research Articles

Generation of Transgenic Rootstock Plum ((Prunus pumila L. × P. salicina Lindl.) × (P. cerasifera Ehrh.)) Using Hairpin-RNA Construct for Resistance to the Plum pox virus

The use of Prunus rootstocks that are resistant to plum pox virus (PPV) is an important agronomic strategy to combat the spread of the Sharka disease in nurseries and orchards. Despite remarkable progress in developing stone fruit rootstocks to adapt to various stresses, breeding that ensures durable virus resistance has not yet been achieved. For this reason, the engineering of PPV resistant plants through genetic transformation is a very promising approach to control sharka disease. The aim of the present study is to produce transgenic plants of the clonal rootstock ‘Elita’, which is resistant to PPV using ribonucleic acid interference (RNAi) technology. The genetic construct containing the self-complementary fragments of the plum pox virus coat protein (PPV-CP) gene sequence were used to induce the mechanism of post-transcriptional gene silencing to ensure virus resistance. Transgenic plants have been produced after agrobacterium-mediated transformation of in vitro explanted leaves. The results of polymerase chain reaction (PCR) and Southern blotting analyses confirmed the stable genomic integration of the PPV-CP sense and antisense intron-hairpin-RNA sequence. The functionality of the introduced expression cassette was confirmed by the activity of including the uidA gene into the transferring T-DNA. To our knowledge, this is the first interspecific plum rootstock produced by genetic engineering to achieve PPV resistance.

The Potential Use of Plant Growth-Promoting Rhizobacteria (PGPR) as Antagonists and Biocontrol Agents in Hevea Diseases

The rhizosphere related bacterial species have a significant capability in plant growth promotion, referred to as Plant Growth Promoting Rhizobacteria (PGPR). Several substances produced by antagonistic rhizobacteria have been related to pathogen control and indirect promotion of growth in many plants. The objectives of this study were to identify effective PGPR bacteria in rubber soils of Sri Lanka, determine the potential use as antagonists and biocontrol agents to control economically important Hevea diseases in nurseries, and identify effective novel inoculant formulations. Soil samples were collected from the root rhizozphere of cover crops in Hevea fields in Rubber Research Institute of Sri Lanka (RRISL), Dartonfield. Bacteria were isolated by TSA plate method. Isolated PGPR bacteria were subjected to test the enzyme secretion ability. Pectinase, Lipase, and Amylase secretion ability of PGPR were tested in specifically developed media. Auxin production of PGPR were measured using freshly prepared Salkowsky reagent. Phosphorous solubilizing ability of PGPR was tested using Pikovskaya (PVK) medium. Antagonistic ability of PGPR was tested against the Rigidoporous microporus, Fusarrium sp. and Pythium sp. causing white root disease and Patch Canker disease in rubber respectively. Paper disc diffusion method was used to test the antagonism of selected bacteria and the percentage growth inhibition was calculated. Plasmid DNA extraction of antagonistic PGPR was done following the alkaline SDS method. Gene sequencing of selected bacteria was further carried out. Among 13 selected PGPR bacterial species, 3 bacteria were showing significant antagonism towards R. microporus. (Percentage growth inhibition by 51.2%, 46.8% and 44.3% respectively) Fusarium sp. was controlled by 7 PGPR species. Pythium sp. was controlled by 2 PGPR (Percentage growth inhibition by 41.6% and 38.7% respectively) 5 types of combinations of bacteria were tested. Among 5 types, 2 types were highly effective in control of R. microporus (Percentage growth inhibition by 79.8% and 72.6% respectively). All 5 combinations were moderately effective in control Fusarium sp. and 1 type was highly effective in control of Pythium sp. (Percentage growth inhibition by 67.8%). PGPR can be used as effective biocontrol agents in control of Hevea pathogens. The combinations of PGPR are more effective than the individual bacterial species. This will be leading to improve the productivity of Hevea plantations in Sri Lanka. Keywords: Plant Growth Promoting Rhizobacteria, Antagonism, Hevea pathogens

<b>An annotated checklist of microbes associated with bamboo in the Indian subcontinent</b>

In India, the area occupied by bamboo is found to be around 1,003 hectares with about 23 genera and 128 species. The most common and economically important bamboo species are Bambusa bambos, B. nutans, B. tulda, B. vulgaris, Dendrocalamus hamiltonii, D. strictus, Ochlandra travancorica and Melacona baccifera. The present paper deals with the appraisal of the bamboo microbes in India encountered on different species of bamboo, along with their taxonomic status, the details of diseases/infection, and the location of reporting and the author. Records of association of microbes/ pathogens on bamboo are scattered in a wide array of journals, books and dissertations. Hence, this comprehensive checklist of microbes associated with bamboo in India has been prepared. This review documents the data of the known 432 microbes associated with bamboo belonging to 12 phyla and 46 orders. The fungal associations have diverse habits- as saprobes, pathogens and also as symbionts. Pathogens belonging to the phylum Deuteromycota were the highest (39.35%), followed by 26.85% in Ascomycota and 20.83% in Basidiomycota. Some of the phyla had pathogens causing various diseases. The highest record of the foliage disease incidence was 40.99% and 24.12% respectively by pathogenic ‘Ascomycota’ and ‘Deuteromycota’. Among Basidiomycota, pathogens causing culm diseases were the highest (26.25%), 66.66% of pathogens belonging to Phylum Proteobacteria were responsible for causing infection of seeds. Among the viral diseases, foliage diseases were more (75%). Myxomycetes were observed to cause the decay and deterioration of bamboo culms upto about 54.54%. It was observed that fungal isolates belonging to the order Moniliales dominated in causing foliage diseases (22.75%), culm diseases (25.36%), and nursery diseases (45.1%) and also infection of seeds (77.94%).

Spore Dispersal Patterns of Fusarium circinatum on an Infested Monterey Pine Forest in North-Western Spain

The airborne inoculum of Fusarium circinatum Nirenberg & O’Donnell, the fungal pathogen causing Pine Pitch Canker (PPC), is one of the main means of spread of the disease in forest stands and forest nurseries. Since this world-wide known pathogen was introduced in Europe, its biology in this newly infested area still remains scarcely known. To shed more light on this topic, we set up an experiment on a naturally PPC infested forest of Monterey pine in Galicia (NW Spain) with the following two goals: (i) to describe the seasonal spore dispersal pattern during one year of regular sampling and (ii) to assess the spatial spore dispersal pattern around the infested plot. Portable rotating arm spore traps were used and complemented with meteorological measurements. The abundance of F. circinatum spores in the samples was assessed by quantitative PCR (qPCR) with a hydrolysis probe. The results showed almost permanent occurrence of the air inoculum throughout the whole year, being detected in 27 of the 30 samplings. No clear temporal trends were observed, but a higher air inoculum was favoured by previous lower air temperatures and lower leaf wetness. Conversely, neither rainfall nor air humidity seemed to have any significant importance. The spatial spread of the inoculum was noted to be successful up to a distance of 1000 m in the wind direction, even with winds of just 5 m·s−1. Our study shows that rotating arm spore traps combined with qPCR may be an efficient tool for F. circinatum detection.

Mapping of QTLs associated with resistance to common bunt, tan spot, leaf rust, and stripe rust in a spring wheat population

Spring wheat (Triticum aestivum L.) breeding goals in western Canada include good agronomic characteristics and good end-use quality, and also moderate to elevated resistance to diseases of economic importance. In this study, we aimed to identify quantitative trait loci (QTL) associated with resistance to common bunt (Tilletia tritici and Tilletia laevis), tan spot (Pyrenophora tritici-repentis), leaf rust (Puccinia triticina), and stripe rust (Puccinia striiformis f. sp. tritici). A total of 167 recombinant inbred lines (RILs) derived from a cross between two spring wheat cultivars, ‘Attila’ and ‘CDC Go’, were evaluated for reactions to the four diseases in nurseries from three to eight environments, and genotyped with the Wheat 90K SNP array and three gene-specific markers (Ppd-D1, Vrn-A1, and Rht-B1). The RILs exhibited transgressive segregation for all four diseases, and we observed several lines either superior or inferior to the parents. Broad-sense heritability varied from 0.25 for leaf rust to 0.48 for common bunt. Using a subset of 1203 informative markers (1200 SNPs and 3 gene-specific markers) and average disease scores across all environments, we identified two QTLs (QCbt.dms-1B.2 and QCbt.dms-3A) for common bunt, and three QTLs each for tan spot (QTs.dms-2B, QTs.dms-2D, and QTs.dms-6B), leaf rust (QLr.dms-2D.1, QLr.dms-2D.2, and QLr.dms-3A), and stripe rust (QYr.dms-3A, QYr.dms-4A, and QYr.dms-5B). Each QTL individually explained between 5.9 and 18.7% of the phenotypic variation, and altogether explained from 21.5 to 26.5% of phenotypic and from 52.2 to 86.0% of the genetic variation. The resistance alleles for all QTLs except one for stripe rust (QYr.dms-5B) were from CDC Go. Some of the QTLs are novel, while others mapped close to QTLs and/or genes reported in other studies.

The occurrence of viruses and viroids in ornamental citrus mother plants in Tuscany (Central Italy)

Citrus tristeza closterovirus (CTV) has been found several times in the last decades in Italy, and plant protection services are involved in monitoring and surveillance. Although orchards linked to the citrus industry are well monitored, there is an underestimated risk of viruses or virus-like diseases in ornamental nurseries. Our aim was to modify a CTV monitoring program to include other viruses (Citrus variegation virus, CVV; Citrus psorosis virus, CPsV) and viroids (Citrus exocortis viroid, CEVd; Hop stunt viroid, HSVd; Citrus bent leaf viroid, CBLVd; Citrus dwarfing viroid, CDVd; Citrus bark cracking viroid, CBCVd). Ornamental mother plants were monitored for four years in 15 nurseries in two locations in central Italy using inexpensive multiplex RT-PCR protocols. CTV incidence was 1.6–13.5%, with an average distribution of 11.9%. The average incidence of CVV and CPsV was 6.3% and 2.7%, respectively. Higher CTV, CVV and CPsV incidences were observed in C. x paradisi, C. grandis and C. x clementina. The most widespread viroid identified was CEVd (32.9%), frequently observed in C. x limonia and C. limon. HSVd (10.5%), and CDVd (7.1%) were mostly found in C. x limonia. Lower infection rates were observed for CBLVd (2.0%) and CBCVd (1.4%). However, the nurseries’ response to the virus alert by the protection services was only partially effective. Although the CTV incidence was lower in nurseries re-checked after the initial detection, it was not eradicated from two nurseries out of three, and the occurrence of viroids was reduced in just one nursery. Given that dangerous viruses along with the concomitant spread of viroids have unfortunately become a fact of every day life, multiplex RT-PCR diagnoses are likely to play an increasing role in warning nursery managers of possible infections.

English

Chitosan and chitin sources have emerged as promising groups of biological substances that can induce plant growth and resistance to diseases. This study is aimed at investigating the potential effect of chitosan and snail shell to promote cocoa growth and induce resistance against Phytophthora megakarya. The results showed that treatment of cocoa seeds with chitosan at 1.5 to 2.0% and snail shell at 2.0% increases the percentage of germination and also reduces the time of germination. 12 weeks after planting, a series of morphological changes was observed on the plants treated with chitosan and snail shell. Plant height (34 to 39.5 cm), leaf number (11 to 13 leaves/plant), leaf area (88 to 130 cm2) and fresh weight of roots and shoots (25 to 44 g/plant) increased significantly in the chitosan and snail shell treated soils. Pods inoculated with chitosan and/or snail shell treated soil suspensions presented very slight necrotic lesions. This could be linked to a decrease in the P. megakarya load of the soil suspension. Leaf inoculation showed variation among the treatments with the lowest index (highest level of resistance) recorded in plants treated either with chitosan or snail shell. The treatment of plants with chitosan and snail shell powder before and after inoculation showed higher level of phenolic compounds than in the control plants. Furthermore, the inoculation induced a significant accumulation of proteins in the cocoa plants treated with chitosan and snail shell. The level of proteins accumulation after inoculation was higher in plants treated with snail shell than those treated with chitosan. In conclusion, the effect of snail shell on cocoa growth and resistance showed that it is possible for snail shell powder to be a biofungicide and biofertilizer used in the control of cacao Black Pod Disease in nurseries. Key words: Theobroma cacao, Phytophthora megakarya, black pod disease, chitosan, snail shell, biocontrol agents.

Regulation of gene expression for defensins and lipid transfer protein in Scots pine seedlings by necrotrophic pathogen Alternaria alternata (Fr.)

Abstract Damping-off disease in pine seedling, caused by fungi and oomycetes (Fusarium, Alternaria, Botrytis, Phytophthora) and other species, is one of the most dangerous diseases in conifer nurseries and greenhouses worldwide. Alternaria alternata is a necrotrophic pathogen, which causes early blight in higher plants and results in massive economic losses in agro-industry as well as in forestry. Pine seedlings that lack strong lignificated and suberized cell walls at early stages of their growth are vulnerable to damping-off disease. So, triggering the synthesis of antimicrobial compounds, such as phytoalexins, anticipins and pathogenesis-related (PR) proteins, is the main defense strategy to confine pathogens at early stages of pine ontogenesis. Defensins and lipid transfer proteins are members of two PR-protein families (PR-12 and PR-14 respectively) and possess antimicrobial activities in vitro through contact toxicity, and the involvement in defense signalling. In this work, we describe the changes in the expression levels of four defensin genes and lipid transfer protein in Scots pine seedlings infected with A. alternata. The expression levels of PsDef1 and PsDef2 increased at 48 h.p.i. (hours post inoculation). The levels of PsDef4 transcripts have increased after 6 and 24 hours. Notably, at 48 h.p.i., the level of PsDef4 transcripts was decreased by 1.2 times compared to control. The level of PsDef3 transcripts was reduced at all three time points. On the other hand, the level of PsLTP1 transcripts increased at 6 h and 48 h.p.i.; while at 24 h.p.i., it decreased by 20% when compared to the control sample. Our results suggest that defensins and lipid transfer protein are involved in the defense response of young Scots pine to necrotrophic pathogen. Thus, those genes can be used as the molecular markers in forestry selection and development of the ecologically friendly remedies for coniferous seedlings cultivation in greenhouses and nurseries.

An overview of diseases in fish hatcheries and nurseries

Quality and healthy fish seed is the prerequisite for sustainable aquaculture. A major challenge to the expansion of aquaculture production is the outbreak of diseases. Disease induced mortality is a serious issue for the fish seed industry. The immature immune system in fish makes the early developmental stages more susceptible to infectious diseases. Common fish diseases in hatcheries and in early rearing systems are caused by protozoan, ciliates, myxosporodians, worms, opportunistic bacteria and fungi. Production of healthy fish seed and survivality depends on the proper health management, maintenance of good water quality, proper nutrition and application of biosecurity measures. The paper highlighted the different types of diseases, causative agents and their prevention and control measures in fish hatcheries and nurseries.

Biocomes: new biological products for sustainable farming and forestry

Abstract: The growing interest in biological control has been reflected during last decades in a big number of scientific publications, books and symposia. However, biocontrol commercial application at a European level is limited and biological control products are not currently available for the control of important pests and diseases that cause high economic losses. The objective of the European project BIOCOMES is to develop 11 new biocontrol products to control key pests and diseases present in agricultural and forestry crops, as a suitable and environmental-friendly alternative strategy to chemical products. BIOCOMES includes 13 private companies (most of them SEMs) and 14 research centres from 14 different countries, working together to develop tools and give solutions to the Integrated Pest Management in Europe. Main targeted pests and diseases are: gypsy moth and large pine weevil in forestry, tomato leaf miner, potato moths, whitefly in vegetables, aphids in fruit tree crops, cabbage moth, brown rot in stone fruit, fungal root diseases in nurseries, Fusarium in cereals, soil-borne Verticillium wilt in Brassica and powdery mildew in cereals. Developed biocontrol products are parasitoids, entomopathogenic nematodes, viruses, bacteria and fungi, and at the end of the project, most of them will be at a stage close to market implementation. Brown rot in stone fruit is the only postharvest disease studied in BIOCOMES and the objective is to complete the development of the biocontrol agents Penicillium frequentans 909 (INIA) and Bacillus subtilis CPA-8 (IRTA) to obtain products that provide an effective strategy to control brown rot in stone fruit production. The growing interest in biological control has been reflected during last decades in a big number of scientific publications, books and symposia. However, biocontrol commercial application at a European level is limited and biological control products are not currently available for the control of important pests and diseases that cause high economic losses. The objective of the European project BIOCOMES is to develop 11 new biocontrol products to control key pests and diseases present in agricultural and forestry crops, as a suitable and environmental-friendly alternative strategy to chemical products. BIOCOMES includes 13 private companies (most of them SEMs) and 14 research centres from 14 different countries, working together to develop tools and give solutions to the Integrated Pest Management in Europe. Main targeted pests and diseases are: gypsy moth and large pine weevil in forestry, tomato leaf miner, potato moths, whitefly in vegetables, aphids in fruit tree crops, cabbage moth, brown rot in stone fruit, fungal root diseases in nurseries, Fusarium in cereals, soil-borne Verticillium wilt in Brassica and powdery mildew in cereals. Developed biocontrol products are parasitoids, entomopathogenic nematodes, viruses, bacteria and fungi, and at the end of the project, most of them will be at a stage close to market implementation. Brown rot in stone fruit is the only postharvest disease studied in BIOCOMES and the objective is to complete the development of the biocontrol agents Penicillium frequentans 909 (INIA) and Bacillus subtilis CPA-8 (IRTA) to obtain products that provide an effective strategy to control brown rot in stone fruit production.

Integrated Management for the Reduction of Calonectria Infections in Ornamental Nurseries.

Chemical control represents the main effective strategy for managing Calonectria diseases in ornamental nurseries. The occurrence of fungicide-resistant strains and the European Directive on "Sustainable Use of Pesticides" has forced ornamental plant growers to establish effective integrated pest management strategies to control Calonectria infections. Here, three nursery experiments were performed to detect the best combinations of fungicides and biological control agents (BCA) to control both leaf spot, caused by six Calonectria spp. on bottlebrush and metrosideros, and stem rot, caused by Calonectria morganii on Dodonaea plants. Overall, the cyprodinil + fludioxonil mixture alone or combined with bioformulates containing Bacillus, Trichoderma, and Streptomyces spp. provided the best performance in reducing leaf spot and stem rot caused by Calonectria spp., followed by the mixture of boscalid + pyraclostrobin. Although BCA alone provided disease suppression significantly lower than the controls in most cases, these treatments were, on average, the least effective in controlling Calonectria infections. Otherwise, there were no significant increases in efficacy with fungicides plus BCA over fungicides alone. Thus, the application of boscalid + pyraclostrobin and cyprodinil + fludioxonil mixtures may also be used in large-scale applications to reduce Calonectria diseases because they effectively managed leaf and stem infections. Our comprehensive research applied previously acquired information on Calonectria disease management in nurseries, resulting in important data that affects integrated plans to fight these pathogens in accordance with European legislation.

Mexican periwinkle virescence phytoplasma associated with phyllody and virescence in strawberry (Fragaria x ananassa Duch.) in Michoacan, Mexico

The strawberry phyllody is considered a reversion of floral reproductive organs, such as achenes in vegetative structures, which can be infectious and non-infectious. The objective of this research was to determine the regional distribution and incidence of phyllody in two strawberry growing areas in Michoacan, Mexico and to determine whether these symptoms are associated with the presence of phytoplasmas. The study comprised 51 strawberry plots distributed in the municipalities of Zamora, Jacona, Tangancicuaro, Chilchota and Maravatio, during the production season, 2014–2015. Phyllody incidence was estimated in 40 plants per plot (five sampling points, eight plants each) distributed approximately equidistant in a zig-zag scheme. Twenty-eight of these samples were used to run a nested PCR protocol for phytoplasma detection; primers P1/P7 were used to amplify a fragment of approximately 1800 bp, and primers P1A/ 16S SR were used to amplify a fragment of approximately 1500 bp, in the first and second reactions, respectively. The strawberry phyllody was found widely distributed with incidence levels up to 35 %. These symptoms were associated with the presence of Mexican Periwinkle Virescence Phytoplasma (MPV). This report is the first to describe this phytoplasma in strawberry in Mexico in the municipalities of Zamora, Jacona, Tangancicuaro, Chilchota and Maravatio in the state of Michoacan. The results will be used to design strategies for managing the disease in commercial nurseries and commercial plantings of strawberry.

Management of bakanae and bacterial seedling blight diseases in nurseries by irradiating rice seeds with atmospheric plasma

The control of seedborne rice seedling diseases in the seed beds is important to avoid epidemics in rice nurseries and paddies, which may result in severe yield loss. Recently, irradiation with plasma containing electrons, creating positive or negative ions and neutral species, has been shown to have an antimicrobial effect, probably via generation of reactive oxygen species. This study examines whether two seedborne rice seedling diseases, bakanae disease caused by the fungal pathogen Fusarium fujikuroi, and bacterial seedling blight caused by Burkholderia plantarii, are suppressed by irradiation of infected rice seeds with atmospheric plasma. Seed germination and seedling growth were not inhibited in plasma‐treated healthy seeds. When F. fujikuroi‐infected rice seeds were irradiated with plasma after being immersed in sterile distilled water, bakanae disease severity index and the percentage of plants with symptoms were reduced to 18.1% and 7.8% of non‐irradiated control, respectively, depending on the duration of plasma irradiation. The bacterial seedling blight disease index was also reduced by plasma irradiation in vacuum‐inoculated seeds to 38.6% of the non‐irradiated control, and in infected seeds harvested from spray‐inoculated heads of rice plants to 40.1% of the control. Therefore, plasma irradiation seems to be effective in controlling two independent seedborne rice seedling diseases.

Prevalence and Eco-Friendly Management of Some Important Nursery Diseases of Mango in Bangladesh

<p>A survey was carried out to record the prevalence of the nursery diseases in four mango varieties (Gopalbhog, Langra, Amropali and Seedless) in some selected growing areas viz. Chapai Nawabganj, Rajshahi, Dinajpur and Mymensingh in Bangladesh. Altogether nine different diseases viz. anthracnose, die-back, malformation, scab, powdery mildew, sooty mould, red rust, gummosis and bacterial leaf spot were recorded during the period of survey. All the diseases were found in the nurseries of Chapai Nawabganj, but Gummosis was not observed in Rajshahi, Dinajpur and Mymensingh and die-back was also not found in Dinajpur. Only anthracnose was recorded in Kajla sinduri in Rajshahi and Kancha mithi in Dinajpur. Out of the 40 mango varieties surveyed occurrence of higher number of diseases were recorded in Amropali (9), Mollica (7), Langra (8), Aswina (8), Khirsapat (8), Fazli (8), Vustara (6), Bogra gooti (6), BARI Aam-2 (6), BARI Aam-4 (6), Mohananda (5), Polyembryony (7), Gopalbhog (7), Hybrid 10 (6), Nilambari (6), Mixed special (6) and Seedless (7). The efficacy of BAU-Biofungicide and four different fungicides viz. Amistar, Tilt 250 EC, Bavistin and Dithane M-45 in the nursery of four mango varieties (Gopalbhog, Langra, Amropali and Seedless) were evaluated in FTIP, Department of Horticulture, Bangladesh Agricultural University, Mymensingh. BAU-Biofungicide showed good effect in controlling anthracnose, die-back, powdery mildew, bacterial leaf spot and sooty mould of mango whereas Dithane M-45 was found best for controlling red rust of mango. Dithane M-45 followed by BAU-Biofungicide and Bavistin resulted reduction of powdery mildew incidence over control while the severity of powdery mildew was lowest in Bavistin followed by Dithane M-45 and BAU-Biofungicide.</p>

Genome sequences of six Phytophthora species associated with forests in New Zealand.

In New Zealand there has been a long association of Phytophthora diseases in forests, nurseries, remnant plantings and horticultural crops. However, new Phytophthora diseases of trees have recently emerged. Genome sequencing has been performed for 12 Phytophthora isolates, from six species: Phytophthora pluvialis, Phytophthora kernoviae, Phytophthora cinnamomi, Phytophthora agathidicida, Phytophthora multivora and Phytophthora taxon Totara. These sequences will enable comparative analyses to identify potential virulence strategies and ultimately facilitate better control strategies. This Whole Genome Shotgun data have been deposited in DDBJ/ENA/GenBank under the accession numbers LGTT00000000, LGTU00000000, JPWV00000000, JPWU00000000, LGSK00000000, LGSJ00000000, LGTR00000000, LGTS00000000, LGSM00000000, LGSL00000000, LGSO00000000, and LGSN00000000.

Identifying practices likely to have impacts on grapevine trunk disease infections: a European nursery survey

A questionnaire covering all aspects of grapevine propagation including cultural and sanitation practices in mother blocks and harvest and transport of cuttings from mother blocks to nurseries, nursery operations and field nursery management, was mailed to all Management Committee members of the European COST Action FA1303 “Sustainable Control of Grapevine Trunk Diseases” for distribution to the identifiable nurseries in each European country. The main objective was to develop understanding of the current propagation practices and to identify those likely to have the greatest impacts on the quality of planting material, especially with regard to the control measures used against fungal trunk pathogen infections. The questionnaire was sent to 666 vine nurseries, and 146 replies were received (21.9% response rate) The study identified several risks factors which could increase infection by fungal trunk pathogens during the propagation processes, as well as a clear need for further research into the effects of treatments on grapevine viability, including hot water treatment, and the potential of biological agents and other strategies such as ozonation to control grapevine trunk diseases in nurseries.

Phakopsora myrtacearum sp. nov., a newly described rust (Pucciniales) on eucalypts in eastern and southern Africa

Outbreaks of a rust disease in eucalypt forestry plantations and nurseries in Kenya, Mozambique and South Africa occurred between 2009 and 2014. The pathogen was identified using morphology and molecular phylogenetic analyses as an undescribed species in the Phakopsoraceae. A systematic study, based on nuclear ribosomal DNA, showed that it is a species of Phakopsora, herein named Phakopsora myrtacearum sp. nov. This new species of rust is the second validly described species on Eucalyptus, along with Puccinia psidii. Phakopsora myrtacearum is distinguished from P. psidii by leaf symptoms, morphology of the urediniospores and distinct phylogenetic placement. Phakopsora myrtacearum has been found on three species of Eucalyptus in Kenya, Mozambique and South Africa, and it may have future negative implications for commercial forestry in these areas.

Weather Impact on Nursery Diseases of Mango Saplings in Bangladesh

The study was carried out during the period of July 2010 to April 2012 to find out the effect of weather prevalence of seedling diseases ofmango in different areas of Bangladesh. The locations were Mymensingh Dinajpur, Rajshahi and Khagrachari. Altogether 12 nurseries in fourdistricts of Bangladesh were surveyed and mango seedling diseases were recorded. Incidence and severity of important seedling diseases ofhas been studied under different geographical locations (viz. Mymensingh, Dinajpur, Rajshahi and Khagrachari) of Bangladesh. The effects oftemperature, rainfall, and relative humidity on the incidence and severity of noted diseases were observed the aforesaid locations of Bangladesh.The studied diseases were anthracnose, leaf spot, red rust, powdery mildew, scab, bacterial leaf blight and malformation of mango seedlings.The graphs of weather parameters and incidence and severity of diseases were performed to determine the relationship between differentcomponents of climatic factor and seedling diseases of mango.DOI: http://dx.doi.org/10.3126/ijasbt.v3i1.11846 Int J Appl Sci Biotechnol, Vol. 3(1): 42-49

Phytochemical Composition, Antimicrobial Effect of Azadirachta indica and Carica papaya Extracts on Fungi Isolated From Gmelina arborea Seedling

Gmelina arborea Roxb has important economic value in Nigeria and worldwide. It has been used as timber, for pulp and paper, furniture, plywood and for particle board. Due to the menace caused by fungal diseases in nurseries and sites where the seedlings are raised and the observed disease severity at the Awi Gmelina Forestry Project Nursery in Cross River State, Nigeria. It became necessary to provide a viable environmentally friendly measure to curb the diseases, hence, a trial on the antifungal effects of leaf extracts of Carica papaya and Azadirachta indica in-vitro using different extract solvents on some pathogenic fungi isolated from Gmelina arborea seedlings. The isolated fungi were Trichoderma viride (from stem and leaf) and Mucor mucedo (stem and leaf). The solvents used were ethanol, methanol, propanol, butanol, acetone, chloroform and distilled water. Phytochemical screening of extracts of C. papaya from the different solvents showed that there was no tannin and hydroxymethyl anthraquinine. Flavonoids and polyphenols were in excess in acetone and methanol extracts respectively. For A. indica, polyphenols were only found in excess in ethanol and methanol extracts. Application of the extracts at different percentages of 0% (control), 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100% showed that Carica papaya extracted with butanol was more potent on Trichoderma viride and Mucor mucedo at 60%, 70%, 80% and 100% while the growth of Trichoderma viride and Mucor mucedo was checked by butanol extracts of A. indica at 70%, 80%, 90% and 100%. Conclusively, butanol extracts of C. papaya and A. indica at higher concentrations is recommended for use as spray to control the diseases.

The possibilities of biologically protecting plants against diseases in nurseries, with special consideration of Oomycetes and Fusarium fungi

Abstract Achieving high quality propagative material is difficult today due to the limited number of pesticides recommended for use. Simultaneously, EU regulations on Integrated Pest Management (IPM) in forest nurseries came into a force, requiring a search for alternative plant protection methods that are safe for humans, animals and the environment. In this paper, we present the possibilities of using bio-fungicides against diseases in forest nurseries, their mechanisms of action, as well as the direction of their development (according to IPM rules). We reviewed the results achieved by different research teams presenting the possibilities and trends in combatting Oomycetes and Fusarium spp. pathogens currently having the most important economic impact.