Strawberry is a high-value crop in Spain, where fruits for fresh consumption are produced off-season and exported to central and northern European countries. Soil-borne pathogens (SBP), such as Macrophomina phaseolina and Meloidogyne hapla, are widely spread in strawberry crops in Spain. The prevalence of these pathogens is a significant barrier to producing strawberries of premium quality and at profitable yields. The current ban on fumigant pesticides drives the search for alternative SBP control methods that can simultaneously control both SBP. Twenty-nine bacterial strains were isolated and identified from strawberry and blueberry rhizospheres and screened for plant growth promotion activities as well as for biocontrol potential on M. phaseolina and M. hapla. Two of these bacterial strains (Bacillus velezensis FC37 and Pseudomonas aeruginosa AC17), together with Brevibacterium frigoritolerans Hvs8 coming from IFAPA’s bacterial collection, were selected and evaluated in planta for their biocontrol potential on strawberry SBP diseases caused by M. phaseolina and M. hapla. The three tested bacterial strains reduced charcoal rot disease severity, crown incidence and severity, and petiole colonization by M. phaseolina. Root-knot nematode (RKN) symptoms were reduced by P. aeruginosa AC17 and B. velezensis FC37, but RKN reproduction was only reduced in plants inoculated with P. aeruginosa AC17. Pseudomonas aeruginosa AC17 showed the greatest potential as a biocontrol agent candidate to be included in integrated disease management programs to control the two most prevalent soil-borne pathogens of strawberry in Spain.

Table olive wastewaters represent a big problem for factories not yet solved. Some partial solutions are the purification, the reuse or the generation of a smaller volume of these liquids. The purpose of this study was to investigate the possibility of obtaining a concentrate that can be stable over time and that has a biofertilizing capacity on tomato ( Solanum lycopersicum L.) plants. In this study, washing waters from Spanish style green and storage liquids from black ripe olive processing were vacuum concentrated up to 10, 13 and 17 times so that they reached total sugar content of up to 700 mmol L −1 , 925 mmol L −1 and 1200 mmol L −1 respectively. Interestingly, the evaporation achieved to retain most of the phenolic compounds that ranged from 18 mmol L −1 in the fresh solution to 140 mmol L −1 in the solution concentrated 10 times. Moreover, these concentrates showed in vitro antimicrobial activity against the bacteria Erwinia amylovora and Pseudomonas syringae, and the Oomycota Phytophthora sp . In addition, they increased the strength and cumulative yield of the tomato plants cultivated under greenhouse conditions, even after 12 months of storage at room temperature. It has been demonstrated that it is possible to reduce the large volume of the wastewaters of the table olive industry, and the concentrates have potential application for agricultural uses, even after 1 year of storage, thereby contributing to a more environmentally sustainable industry. Graphical Abstract

Macrophomina phaseolina, is a pathogenic soil-borne fungus that affects more than 500 plant species, causing various types of disease to several crops, among which is the crown and root rot disease in strawberry. Its wide variability has been characterized reiteratively in the literature, but little is known about its virulence mechanisms. Morphological, physiological, genetic and phytopathogenic parameters were evaluated among 32 isolates of Macrophomina from different hosts occurring in Argentina and Spain. Colony characteristics, average size of microsclerotia, chlorate phenotype and mycelial growth at different temperatures (5º–40 °C), and pH (3.0–8.0) were recorded. The morphological and physiological traits were heterogeneous and did not show any association with the genetic structure nor with their pathogenicity. Most of the isolates (71.9%) exhibited chlorate-sensitive phenotype. The optimal growth temperature range was between 25 °C and 35 °C, and the optimal pH varied between 4.0 and 6.0. The genetic structure analyzed with four DNA markers (EF-1α, ITS, CAL and TUB) showed little diversity among isolates of M. phaseolina, with no clear association with the country of origin, but a significant association with the host. Based on their phylogenetic affinity, one isolate was reclassified as M. pseudophaseolina and another one as M. tecta. It is the first report of M. pseudophaseolina causing charcoal rot on beans, in Argentina, and the first report of M. tecta outside Australia. Pathogenicity tests on strawberry plants revealed marked host specialization, being the isolates obtained from strawberry more virulent than those from other hosts.

Metabarcoding assembled DNA sequences corresponding to a region from the 16S and from the ITS2 of bacteria and fungi, respectively, from blueberry crop soils. Filtered phyloseq R objects with DNA sequences, sample/abundance table, sample metadata and taxonomy.

Microbial interactions in agricultural soils can play important roles in the control of soil-borne phytopathogenic diseases. Yields from blueberry plantations from southern Spain have been impacted by the pathogenic fungus, Macrophomina phaseolina. The use of chemical fungicides has been the common method for preventing fungal infections, but due to their high environmental impact, legislation is increasingly restricting its use. Biocontrol alternatives based on the use of microorganisms is becoming increasingly important. Using the metabarcoding technique, fungi and bacteria were characterized (via 16S and ITS regions, respectively) from rhizosphere soils of healthy and dead blueberry plants infected by M. phaseolina, and which had undergone three different treatments: two biocontrol strategies—one of them a mix of Pseudomonas aeruginosa and Bacillus velezensis and the other one with Bacillus amyloliquefaciens—and a third treatment consisting of the application of a nutrient solution. The treatments produced changes in the bacterial microbiota and, to a lesser extent, in the fungi. The abundance of Fusarium was correlated with dead plants, likely favoring the infection by M. phaseolina. The presence of other microorganisms in the soil, such as the fungi Archaeorhizomyces or the bacteria Actinospica, were correlated with healthy plants and could promote their survival. The different genera detected between dead and healthy plants opens the possibility of studying new targets that can act against infection and identify potential microorganisms that can be used in biocontrol strategies.

Some Plant Growth-Promoting Rhizobacteria (PGPR) can induce protection against pathogens, increasing plant tolerance to various diseases. This so-called biocontrol activity is replacing harmful practices in agriculture caused by the use of agrochemicals. Azospirillum brasilense is one of the PGPR already effectively used as a resistance inducer in several crops. The aim of this study was to evaluate the protective effect of PGPR A. brasilense strains isolated from strawberry and petunia plants (REC3, 2A1, 2A2, and 2E1) against the fungal pathogen Macrophomina phaseolina, which is the causal agent of the strawberry charcoal rot disease. In vitro antagonism assays and enzymatic tests on Petri dishes revealed no direct inhibition on M. phaseolina growth by any of the A. brasilense strains. However, strawberry plants treated with REC3 and 2A1 strains increased callose and lignin deposition and stomatal closure compared to untreated plants. In addition, treatments with either bacterial strains induced a defense response in strawberry plants against virulent isolates of M. phaseolina evidenced by an increased tolerance to the charcoal rot disease. These results suggest that A. brasilense REC3 and 2A1 strains can be used for the activation of innate immunity in strawberry plants as a strategy for managing charcoal rot in a sustainable and environmentally friendly way.

(1) Background: Strawberry cultivation is highly dependent on soil disinfestation for proper development. Since the definitive methyl bromide phase-out, other chemicals have been used as alternatives. This research provides an overview on the efficacies of soil disinfestation methods on controlling soil fungal diseases of strawberry. (2) Methods: The efficacy of several soil disinfestation methods on soil fungal pathogens (SFP: Fusarium spp. and Macrophomina phaseolina) was analyzed in experimental field trials during eleven growing seasons. (3) Results: Average efficiencies in reducing soil pathogen inocula for soil disinfestation techniques are given. Soil disinfestations with chloropicrin, allyl isothiocyanate, dazomet, 1,3-dichloropropene:chloropicrin, methyl iodide:chloropicrin, and dimethyl disulfide reduced Fusarium spp. and M. phaseolina soil inocula by more than 90%. Combination of solarization with organic manures (biosolarization) reduced Fusarium spp. soil populations by 80% and M. phaseolina by 79%. Reductions in plant mortality and increases in fruit yields over the untreated controls did not differ between chemically fumigated and biosolarized plots. (4) Conclusions: Soil fungal pathogens are effectively controlled by chemical fumigation of soils in intensive strawberry crops in Spain. In the case of mixed infestations of SFP with nematodes, the most efficient treatment in suppressing soil-borne diseases was soil fumigation with 1,3-dichloropropene:chloropicrin, but other alternative chemicals, such as allyl isothiocyanate, dazomet, and dimethyl disulfide, provided high efficacies in reducing the SFP inocula. Soil biosolarization is proposed as an effective alternative to chemical soil fumigation for strawberry cultivation in Southern Spain when SFP inocula is not remarkably high.

The effect of antagonistic bacteria to control Macrophomina phaseolina was evaluated under in vitro, growth chamber, greenhouse and field conditions. A total of 177 bacteria, isolated from Athrocaulon macrostachyum rhizosphere of the Lebrija marsh, were screened for their potential against M. phaseolina (causes charcoal rot in strawberry) by dual culture assay. Of these isolates, 14 most promising strains were molecularly identified by the 16S rDNA sequencing method using the EzBioCloud database. These strains were tested for in vitro hydrolytic enzymes, HCN production, and biocontrol against M. phaseolina in strawberry plants. All the 14 strains produced, at least, one hydrolytic enzymatic activity and one of them, which belongs to Brevibacterium genus (Hvs8), showed the lowest records of disease incidence (20%) and severity (0.4). With these results, greenhouse and field trials were carried out with the Hvs8 strain, compared to non-treated control. In the greenhouse assays, Hvs8 strain increased root dry mass by 30%, over the control. In the field trials, production and fruit quality were not significantly different between Hvs8 treatment and non-treated control, but plant mortality and plant mortality associated to M. phaseolina decreased by more than 24% and 65% respectively, in Hvs8 treatment. This study suggests that Brevibacterium sp. Hvs8 strain could be a candidate for controlling charcoal rot in strawberry.

Huelva (Spain) is the largest European producer of blueberry for early spring harvest. Blueberry fields in Huelva are intensively cultured. Canker or stem blight of blueberry and the resultant twig dieback caused mostly by botryosphaeriaceous species has become a serious problem throughout blueberry producing areas worldwide; although the presence of Botryosphaeriaceae species associated with this disease varies. In Huelva, blueberry canker or stem blight has been attributed to Neofusicoccum parvum, N. australe and Lasiodiplodia theobromae. Meanwhile, Macrophomina phaseolina has been associated with blueberry charcoal rot. Plants with cankers and root rot, due to Botryosphaeriaceae species and M. phaseolina respectively, were found frequently. This observation has led to consider the possible interaction of these infections. Thus, blueberry plants from a farm with high canker incidence and severity were sampled, and stems and roots of diseased plants were analysed. The highest number of nearly dead or dead plants was associated with coinfection by N. parvum or L. theobromae and M. phaseolina. For this reason, here, we designed bioassays with inoculations of N. parvum or L. theobromae, with and without M. phaseolina rhizosphere inoculation. The results indicated that canker disease severity increased due to root coinfection of M. phaseolina, depending on the N. parvum or L. theobromae inoculum and the blueberry cultivar. These findings show that the disease is more complex than previously thought, and should be considered in the development of more effective control measures.

This study was aimed at making progress on the valorisation of table olive wastewater that currently represent a big environmental problem for factories. Concentrates from vacuum evaporation of the wastewater generated during processing of black ripe olives treated with KOH were tested as fertilisers of tomato plants in open field assays for three consecutive crops. Fertilisation was performed by drip irrigation every 15 days; the first treatment being 15 days after transplanting, and a total of five fertilisation treatments were carried out. A phytotoxic effect was not observed on plants or fruit in any case but higher yield (fruit/plant and g/plant) was obtained in comparison to irrigation with only tap water. Moreover, the combined use of the olive concentrate with inorganic nitrogen supply (NH4NO3), in order to comply with the nutrient needs of plants, was also tested. The results demonstrated that the olive concentrates could be a good substitute for inorganic potassium (as KNO3) during the cultivation of tomato plants without any negative effect on the tomato quality (pH, °Brix, sugars, organic acids) or content of bioactive substances (phenolic compounds and carotenoids).

Recently, the potential use as fertilizer of some wastewaters from table olive factories has been reported but the cause of this activity has not been disclosed up to now. In this study, a huge number of table olive waste solutions were analyzed from three consecutive seasons. Sugars, phenolic and mineral compounds were the main chemical groups identified. The individual effect of these components was tested on the growth of tomato plants and the quality of their fruits. Two factorial designs were assayed (2(4) and 2(3)), in which the individual groups of chemical substances were sugars, minerals (nitrogen, potassium and phosphor), simple and polymeric phenols. Also, fresh wash water from Spanish-style green table olive processing was tested. The main conclusion was that no one individual group caused the fertilizer activity but a synergetic action of all of them was efficient and the fresh waste solution tested was the most effective.

Table olive wastewaters are seriously polluting and a difficult to treat effluent worldwide, mainly due to their high content in sodium. An alternative approach could be the treatment of the olives with KOH instead of NaOH, in order to reuse the olive streams as biofertilizers. In this study, the debittering of olives with KOH was investigated at pilot plant scale in two olive seasons. The results indicated that a concentration between 1.7 and 2.0% of KOH (similar to that employed with NaOH) led to a fermented product with the same physicochemical and organoleptic characteristics than the traditional one. The spent lyes and washing waters from the KOH treatments were gathered and vacuum evaporated, giving rise to a concentrated solution rich in potassium (52 g/L) that was tested as biofertilizer in open tomato fields. Furthermore, the drip irrigation of the tomato plants with a combined olive solution and mineral fertilizer (NH4NO3) produced similar tomato yield and quality than the irrigation with only mineral fertilizer (NH4NO3 + KNO3). Overall, it has been demonstrated that Spanish-style green olives can be processed with KOH and the effluents valorized to be used as biofertilizer.

Dimethyl disulfide (DMDS) was tested during the period 2012-2016, in shank and drip applications in seven trials carried out in the southern coastal area of Spain (Huelva), which is the main producing area of strawberry in Europe. A complete randomized block design was used with three replications (80 m(2) replicate(-1) and 600 plants replicate(-1)). Strawberry cultivar 'Florida-Fortuna' was used following local cultivation practices under high-tunnel conditions. The soil was sandy (90%) with low organic matter content (0.5-0.75%) and pH ranging from 6.7-7.1. The soil disease complex of strawberry in the area is associated with the presence of several fungi, oomycetes and nematodes, i.e., Macrophomina phaseolina, Phytophthora cactorum, Fusarium spp., Pratylenchus penetrans, Meloidogyne hapla, etc. The following fumigant solutions (straight and combined applications) were used in at least two consecutive seasons representing a minimum three trials: dazomet broadcast application (20 g m(-2)) + DMDS in shank during bed formation (30 g m(-2)), dazomet broadcast application (25 g m(-2)) + DMDS in shank during bed formation (30 g m(-2)), DMDS (30 g m(-2)) + metam sodium (38.3 g m(-2)) both applied by drip, DMDS in shank application (60 g m(-2)), 1,3-dichloropropene + chloropicrin (40 g m(-2)) shank, 1,3-dichloropropene + chloropicrin (40 g m(-2)) drip, and untreated control. Soil fumigations were conducted every year in August and plantings in October. Field evaluations (plant vigor, yield, symptomatic plants) and lab tests (pathogen identification before and after the fumigation, and nematode counting), were carried out in each trial. All fumigant application performed significantly better than the untreated control (average yield of seven trials was 54.1 MT ha(-1)). Among fumigants, the best performance was shown by the combination dazomet (20 g m(-2)) + DMDS (30 g m(-2)) with 78.8 MT ha(-1) (average of two years). DMDS straight at 60 g m(-2) achieved 66.6 vs. 53.3 MT ha(-1) obtained with untreated control in the same conditions. In all cases, DMDS solutions were comparable to 1,3-dichloropropene + chloropicrin in shank and drip applications used as market standard. Therefore, DMDS, once registered, will be a new effective solution to control nematodes and soil fungi in strawberry production in the EU.

The table olive factory generates a large amount of wastewaters and this is a big environmental problem. The aim of this study was to look for a solution of this issue, using table olive waste as irrigation water during the growth of four Mediterranean crops: tomato (Solainan b,copersicum L.), strawberry (Fragaria x ananassa L.), cucumber (Cucumis sativus L.) and pepper (Capsicum annuum L). 'These solutions were rich in sugars (17-85 nunoles L-1) and polyphenolic compounds (13-21 nunoles L-1), being hydroxytyrosol the main component (5.5-14.5 mmoles L-1). Also, some minerals were identified (carbon, nitrogen, sodium, potassium and phosphorus). The solutions were free of sodium chloride and no phytotoxic effect was detected, neither on the fruits or the leaves. The irrigation with the tested solutions originated an increase of the plant growth, fruit size and cumulative yield by at least 20% compared to the dipping and spraying applications mode. Also, it was observed a decrease of the powdery mildew disease in strawberry plants. Particularly, the fruit medium weight of cuctunbers treated with table olive solutions was 40 g higher that the untreated fruits. Among the wastewaters generated during table olive processing, the wash water solution from Spanish-style green olives and the acidified storage liquids from black ripe olive processing could be employed as natural fertilizers and ftmgicide in substitution of synthetic products.

HomePlant DiseaseVol. 103, No. 10First Report of Charcoal Rot, Caused by Macrophomina phaseolina, on Blueberry in Southwestern Spain PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Charcoal Rot, Caused by Macrophomina phaseolina, on Blueberry in Southwestern SpainB. de los Santos, A. Aguado, C. Borrero, J. Viejobueno, and M. AvilésB. de los SantosIFAPA Centro Las Torres, Sevilla, SpainSearch for more papers by this author, A. AguadoIFAPA Centro Las Torres, Sevilla, SpainSearch for more papers by this author, C. Borrero†Corresponding author: C. Borrero; E-mail Address: [email protected]http://orcid.org/0000-0002-6624-2518Departamento de Ciencias Agroforestales, E.T.S.I.A. Universidad de Sevilla, C.P. 41013 Sevilla, SpainSearch for more papers by this author, J. ViejobuenoEstación Experimental Agropecuaria Famaillá, Instituto Nacional de Tecnología Agropecuaria (INTA), T4132, Famaillá, Tucumán, ArgentinaSearch for more papers by this author, and M. Aviléshttp://orcid.org/0000-0002-0077-0713Departamento de Ciencias Agroforestales, E.T.S.I.A. Universidad de Sevilla, C.P. 41013 Sevilla, SpainSearch for more papers by this authorAffiliationsAuthors and Affiliations B. de los Santos1 A. Aguado1 C. Borrero2 † J. Viejobueno3 M. Avilés2 1IFAPA Centro Las Torres, Sevilla, Spain 2Departamento de Ciencias Agroforestales, E.T.S.I.A. Universidad de Sevilla, C.P. 41013 Sevilla, Spain 3Estación Experimental Agropecuaria Famaillá, Instituto Nacional de Tecnología Agropecuaria (INTA), T4132, Famaillá, Tucumán, Argentina Published Online:7 Aug 2019https://doi.org/10.1094/PDIS-04-19-0761-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat In Europe, Huelva Province in southwestern Spain is the main berry production area. Blueberry (Vaccinium spp.) was introduced during the early 1990s as an addition to strawberry cultivation. From 2011 to 2018, blueberry acreage increased from 777 to 3,000 ha. In May 2015 and September 2017, wilted southern highbush blueberry plants (cvs. ‘Star’, ‘Ventura’, and ‘Legacy’) were collected from three orchards located in the Huelva production area (Gibraleón and Moguer). The diseased plants showed drying of foliage and brown discoloration of stems and roots. Roots and stems of symptomatic plants were surface sterilized (2 min,1% sodium hypochlorite), rinsed, dried, and plated on potato dextrose agar (PDA). After 7 days at 30°C in the dark, fungal isolates produced numerous black, round to ovoid shaped sclerotia with an average diameter of 98 μm (range: 61 to 128 μm). Genomic DNA from a single sclerotium isolate (TOR-872) was extracted following the technique described by Bekesiova et al. (1999). Four DNA regions were amplified and sequenced: the exon region of translation elongation factor 1-α (TEF-1 α), β-tubulin (β-TUB), calmodulin (CAL), and the internal transcribed spacer (ITS) region. TEF-1 α was amplified with the EF1-728F and EF1-986R primers (Carbone and Kohn 1999), β-TUB with the T1 and T22 primers (O’Donnell and Cigelink 1997), CAL with the CAL-228F and CAL-737R primers (Carbone and Kohn 1999), and the ITS with the ITS5 and ITS4 primers (White et al. 1990). After BLASTing the four sequences against the GenBank database, the top hits corresponded to Macrophomina phaseolina with a 99 to 100% of sequence identity for all cases. Our sequences were submitted to GenBank under accession numbers MK447854 (TEF-1 α), MK447918 (β-TUB), MK447823 (CAL), and MK447886 (ITS). Morphological and molecular results confirmed this isolate as M. phaseolina (Holliday and Punithaligam 1970). In Gibraleón, in 7.87% of nearly dead plants (cv. Ventura) only M. phaseolina was isolated, whereas in Moguer disease incidence was 30, 7, and 2.27% in cultivars Star, Ventura, and Legacy, respectively. Inoculum for pathogenicity testing was produced by growing isolates TOR-872 and TOR-862 (both from diseased blueberry plants) on PDA. In addition, pathogenicity of M. phaseolina isolate TOR-102, which was from a strawberry soil and confirmed as pathogenic to strawberry, was tested because blueberry is usually cultivated in soils where strawberry had grown. Six potted blueberry plants (cv. Star) per isolate were inoculated by substrate irrigation with 50 ml of a sclerotia suspension (104 sclerotia/ml) of each isolate. Six control plants were irrigated with water. Plants were held at 28°C and 40/70% relative humidity (day/night) in a growth chamber with a 16-h photoperiod. Four months after inoculation, the mortality of the inoculated plants was 33, 50, and 50% for isolates TOR-862, TOR-872, and TOR-102, respectively. M. phaseolina was reisolated from all dead plants. No symptoms were observed in control plants. M. phaseolina has been associated with a blight disease on blueberry in Serbia (Popović et al. 2018), but this is the first report of charcoal rot on blueberry in Spain. The aggressiveness of the strawberry soil isolate was also confirmed on blueberry. In Spain, chemical fumigation in soil is banned in blueberry production. Thus, blueberry may be grown on fields with a previous history of strawberry production, and carryover of M. phaseolina causing charcoal rot may significantly impact crop production.The author(s) declare no conflict of interest.References:Bekesiova, I., et al. 1999. Plant Mol. Biol. Report. 17:269. https://doi.org/10.1023/A:1007627509824 Crossref, ISI, Google ScholarCarbone, I., and Kohn, L. M. 1999. Mycologia 91:553. https://doi.org/10.2307/3761358 Crossref, ISI, Google ScholarHolliday, P., and Punithaligam, E. 1970. Macrophomina phaseolina. Descriptions of Pathogenic Fungi and Bacteria, No. 275. Commonwealth Mycological Institute, Kew, U.K. Google ScholarO’Donnell, K., and Cigelink, E. 1997. Mol. Phylogenet. Evol. 7:103. https://doi.org/10.1006/mpev.1996.0376 Crossref, ISI, Google ScholarPopović, T., et al. 2018. Can. J. Plant Pathol. 40:121. https://doi.org/10.1080/07060661.2017.1415977 Crossref, ISI, Google ScholarWhite, T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA. Crossref, Google ScholarThe author(s) declare no conflict of interest.Funding: Funding was provided by Fresas Nuevos Materiales S.L. (FIUS PRJ201803439) and Junta de Andalucía (cofunded with FEDER funds) (PPAVA2016 01.10).DetailsFiguresLiterature CitedRelated Vol. 103, No. 10 October 2019SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionBell pepper cv. Bomby infected with zucchini yellow mosaic virus along with cucumber mosaic virus, pepper mild mottle virus, and tobacco mosaic virus (Verma et al.). Photo credit: S. Tripathi. Severe stunting, leaf chlorosis, and horizontal head growth of sunflower infected with Plasmopara halstedii, causal agent of downy mildew (Humann et al.). Photo credit: S. Markell. Metrics Article History Issue Date: 3 Oct 2019Published: 7 Aug 2019First Look: 5 Jun 2019Accepted: 31 May 2019 Pages: 2677-2677 Information© 2019 The American Phytopathological SocietyFundingFresas Nuevos Materiales S.L.Grant/Award Number: FIUS PRJ201803439Junta de Andalucía (cofunded with FEDER funds)Grant/Award Number: PPAVA2016 01.10Keywordsfungiberriespathogen detectionVacciniumThe author(s) declare no conflict of interest.Cited byMicrobiota Modulation in Blueberry Rhizosphere by Biocontrol Bacteria12 October 2022 | Microbiology Research, Vol. 13, No. 4Macrophomina phaseolina –host interface: Insights into an emerging dry root rot pathogen of mungbean and urdbean, and its mitigation strategies21 April 2021 | Plant Pathology, Vol. 70, No. 6Increase of canker disease severity in blueberries caused by Neofusicoccum parvum or Lasiodiplodia theobromae due to interaction with Macrophomina phaseolina root infection5 January 2021 | European Journal of Plant Pathology, Vol. 159, No. 3First Report of Root Rot Caused by Macrophomina phaseolina on Atractylodes lancea in ChinaLin Cai, Yongzhi Zhang, Hancheng Wang, Chen Xu, and Xianchao Sun31 August 2020 | Plant Disease, Vol. 104, No. 11Diversity and pathogenicity of Lasiodiplodia and Neopestalotiopsis species associated with stem blight and dieback of blueberry plants in Peru8 May 2020 | European Journal of Plant Pathology, Vol. 157, No. 1

HomePlant DiseaseVol. 102, No. 8First Report of Charcoal Rot Caused by Macrophomina phaseolina on Hemp (Cannabis sativa) Varieties Cultivated in Southern Spain PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Charcoal Rot Caused by Macrophomina phaseolina on Hemp (Cannabis sativa) Varieties Cultivated in Southern SpainS. Casano, A. Hernández Cotan, M. Marín Delgado, I. F. García-Tejero, O. Gómez Saavedra, A. Aguado Puig, and B. de los SantosS. Casano†Corresponding authors: S. Casano, E-mail: E-mail Address: [email protected]; and B. de los Santos, E-mail: E-mail Address: [email protected]http://orcid.org/0000-0002-3243-5397Search for more papers by this author, A. Hernández CotanSearch for more papers by this author, M. Marín DelgadoSearch for more papers by this author, I. F. García-TejeroSearch for more papers by this author, O. Gómez SaavedraSearch for more papers by this author, A. Aguado PuigSearch for more papers by this author, and B. de los Santos†Corresponding authors: S. Casano, E-mail: E-mail Address: [email protected]; and B. de los Santos, E-mail: E-mail Address: [email protected]Search for more papers by this authorAffiliationsAuthors and Affiliations S. Casano † A. Hernández Cotan M. Marín Delgado , Phytoplant Research S.L., The Science and Technology Park of Córdoba, 14014, Córdoba, Spain I. F. García-Tejero O. Gómez Saavedra A. Aguado Puig B. de los Santos † , Instituto Andaluz de Investigación y Formación Agraria y Pesquera (IFAPA) – Centro “Las Torres-Tomejil”, Ctra. Sevilla-Cazalla km. 12’2, 41200, Alcalá del Río, Spain. Published Online:5 Jun 2018https://doi.org/10.1094/PDIS-02-18-0208-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat In June 2015 and July 2016, charcoal rot symptoms were observed in plants of different industrial and medicinal hemp varieties grown in two different fields located in southern Spain (Los Chapatales and Alcalá del Río, Seville). In Los Chapatales, disease incidence was 22% in variety Futura 75. In Alcalá del Río, the medicinal hemp varieties Sara and Aida (disease incidence: 25.5 and 37.1%, respectively) were more susceptible than varieties Theresa (3.8%), Pilar (3.2%), and Juani (2.7%). In both fields, affected plants developed a systemic chlorosis, rapidly wilted, showed necrosis, and died. Before the stalk was completely desiccated, internal tissues appeared soft and fluffy. Discoloration of the stalk was detected near the soil line where small black sclerotia were observed. Roots were necrotic with areas of brown-violet, unprotected vascular cambium. Plant samples were collected from both locations and a fungus was consistently isolated from symptomatic stem tissues that had been surface disinfested and plated on potato dextrose agar (PDA) media. After 7 days of incubation at 30°C in the dark, all isolates produced numerous, dark, ovoidal shaped sclerotia with an average diameter of 114 µm (range: 89 to 141 µm). Based on sclerotial morphology, all isolates were identified as Macrophomina phaseolina (McPartland et al. 2000). An isolate labeled as TOR-840 (from Alcalá del Río) was characterized as susceptible to chlorate, with optimum growth at 25 to 30°C and no growth at 5 or 10°C. Pathogen identification was confirmed by amplifying and sequencing two genetic regions: TEF-1α region (GenBank accession no. MG434668) using primers EF1-728F (Carbone and Kohn 1999) and EF2 (O’Donnell et al. 1998), and CAL region (MG434669) using primers CAL-228F and CAL-737R for PCR amplification (Carbone and Kohn 1999). Sequences were compared with those in the NCBI GenBank database using a BLAST search and had 99% nucleotide sequence identity with M. phaseolina for CAL region and 100% for TEF-1α region. Inoculum for pathogenicity tests was produced by growing isolate TOR-840 in PDA media. After 1 week, six plants for each variety (Sara and Pilar, the most and the least susceptible in field trials, respectively) were inoculated by substrate irrigation of each plant with 150 ml of a sclerotia suspension (104 sclerotia/ml). Plants were held at 27°C and 50/70% relative humidity (day/night) in a growth chamber with a 16-h photoperiod. Pathogenicity assays were carried out in a randomized complete block design with three blocks of two plants each. After 3 months of incubation, the mortalities of the inoculated plants were 83.3 and 16.7% for Sara and Pilar, respectively. No mortality was observed in control plants. Although Pilar had lower mortality rates than the variety Sara, M. phaseolina was reisolated from stems and petioles of 83.3% of the inoculated plants in both varieties. Charcoal rot has been reported on Cannabis sativa L. varieties in Italy, Cyprus, the United States of America, and Yugoslavia (McPartland et al. 2000). Considering that M. phaseolina has been reported in several crops in southern Spain and that effective control measures have not yet been found, susceptible hemp varieties are discouraged to be cultivated and suitable crop rotations must be ensured.References:Carbone, I., and Kohn, L. M. 1999. Mycologia 91:553. https://doi.org/10.2307/3761358 Crossref, ISI, Google ScholarMcPartland, J. M., et al. 2000. Hemp Diseases and Pests. Management and Biological Control. CABI Publishing, Wallingford, U.K. Google ScholarO’Donnell, K., et al. 1998. PNAS 95:2044. https://doi.org/10.1073/pnas.95.5.2044 Crossref, ISI, Google ScholarDetailsFiguresLiterature CitedRelated Vol. 102, No. 8 August 2018SubscribeISSN:0191-2917e-ISSN:1943-7692 Metrics Article History Issue Date: 18 Jul 2018Published: 5 Jun 2018First Look: 7 Mar 2018Accepted: 5 Mar 2018 Page: 1665 Information© 2018 The American Phytopathological SocietyCited byMacrophomina phaseolina (charcoal rot of bean/tobacco)CABI Compendium, Vol. CABI CompendiumMolecular Diagnostics and Pathogenesis of Fungal Pathogens on Bast Fiber Crops18 March 2020 | Pathogens, Vol. 9, No. 3