Species Of Lasiodiplodia Research Articles

Enhancing epidemiological knowledge of Botryosphaeriaceae in Mexican vineyards

Grapevine cultivation in Mexico is important, especially in the states of Baja California and Coahuila, which are the main wine production regions in the country. Grapevine trunk diseases (GTDs) impact productivity and cause substantial economic losses, with Botryosphaeria dieback being one of the most destructive. This disease is caused by fungi in the Botryosphaeriaceae, including species of Botryosphaeria, Diplodia, Lasiodiplodia, and Neofusicoccum. To date, Lasiodiplodia spp. are the primary Botryosphaeriaceae fungi reported in Mexico. The present study aimed to enhance the epidemiological knowledge of Botryosphaeriaceae in Mexican vineyards. Samples from grapevine plants exhibiting disease symptoms were collected from the states of Baja California and Coahuila. Of a total of 37 Botryosphaeriaceae isolates, six species were identified: Neofusicoccum parvum, N. australe, N. vitifusiforme, Botryosphaeria dothidea, Diplodia corticola, and D. seriata. Neofusicoccum parvum isolates were the most virulent, but were less virulent than previously reported Lasiodiplodia spp. The optimum growth temperatures for N. parvum and B. dothidea were from 28 to 30°C, but 25°C for D. seriata, N. vitifusiforme, and N. australe isolates. Only D. seriata isolates recovered growth when transferred to room temperature after exposure to 37°C or 40°C. This report is the first identification of B. dothidea and N. parvum as causative agents of Botryosphaeria dieback in the vine-growing regions of Mexico.

Phylogenetic and Pathogenic Evidence Reveals Novel Host-Pathogen Interactions between Species of Lasiodiplodia and Citrus latifolia Dieback Disease in Southern Mexico.

Mexico ranks second in the world for Persian lime (Citrus latifolia) exports, making it the principal citrus exporter within the national citrus industry, exporting over 600,000 tons per year. However, diseases are the main factor reducing production, resulting in significant economic losses. Among these diseases, fungal diseases like dieback, caused by species of Lasiodiplodia, are an emerging issue in Persian lime. Symptoms include gummosis, twig and branch dieback, cankers, the necrosis of bark and wood, fruit mummification, and tree decline. The aim of this study was to investigate the occurrence and pathogenicity of the fungal species associated with twig and branch dieback, cankers, and decline of Persian lime trees in southern Mexico, and to elucidate the current status of the Lasiodiplodia species causing the disease in Mexico. During June, July, and August of 2023, a total of the 9229 Persian lime trees were inspected across 230 hectares of Persian lime orchards in southern Mexico, and symptoms of the disease were detected in 48.78% of the trees. Branches from 30 of these Persian lime trees were collected. Fungal isolates were obtained, resulting in a collection of 40 strains. The isolates were characterized molecularly and phylogenetically through the partial regions of four loci: the internal transcribed spacer region (ITS), the β-tubulin gene (tub2), the translation elongation factor 1-alpha gene (tef1-α), and the DNA-directed RNA polymerase II second largest subunit (rpb2). Additionally, pathogenicity was assessed, successfully completing Koch's postulates on both detached Persian lime branches and certified 18-month-old Persian lime plants. Through multilocus molecular phylogenetic identification, pathogenicity, and virulence tests, five species were identified as causal agents: L. iraniensis, L. lignicola, L. mexicanensis, L. pseudotheobromae, and L. theobromae. This study demonstrates that in southern Mexico, at least five species of the genus Lasiodiplodia are responsible for dieback in Persian lime. Additionally, this is the first report of L. lignicola and L. mexicanensis as causal agents of the disease in citrus, indicating novel host interactions between species of Lasiodiplodia and C. latifolia.

First report of Lasiodiplodia hormozganensis and Lasiodiplodia laeliocattleyae causing crown rot disease in banana fruits in Brazil

Bananas are the most widely produced fruit in the world. Crown rot, one of the main postharvest diseases of banana fruit, causes significant losses during storage, transportation, and marketing. Different fungi, especially species of the genus Lasiodiplodia, are associated with this disease. Lasiodiplodia isolates were obtained from asymptomatic fruits in the states of Alagoas, Ceará and Pernambuco, Brazil. On Potato Dextrose Agar (PDA), the isolates initially produced moderately dense grayish-white mycelium, then turned olive green to grayish-black, with olive-green or black reverses. The fungal isolate was classified as Lasiodiplodia hormozganensis and Lasiodiplodia laeliocattleyae based on morphological and multigene (TEF1-α, ITS and TUB2) phylogenetic analysis. Pathogenicity tests were performed by inoculating mycelial discs containing pathogen structures on banana fruits, confirming Koch's postulates. This is the first report of L. hormozganensis and L. laeliocattleyae causing crown rot disease in banana plants in the world.

Identity, Pathogenicity, and Genetic Diversity of Lasiodiplodia Species Associated with Stem-End Rot of Avocado in China.

Stem-end rot (SER) causes brown necrotic lesions in the pulp near the base of the fruit pedicel and is one of the most devastating postharvest diseases of avocados in all avocado-growing regions of the world. China's avocado industry is growing very rapidly, and the planting area is expanding, but little is known about the pathogens and genetic diversity of avocado SER. To determine the causal agents of SER, avocado fruits were sampled from the main avocado-producing areas in China during 2020 and 2021. Fungal isolates were obtained from SER symptomatic avocado fruits and identified by morphology combined with phylogenetic analysis of internal transcribed spacer (ITS), translation elongation factor 1-α (EF1-α), and β-tubulin (TUB2) gene sequences. All 101 isolates belonged to Lasiodiplodia spp.; four Lasiodiplodia species were identified, namely, L. pseudotheobromae (59.41%), L. theobromae (24.75%), L. mahajangana (7.92%), and L. euphorbiaceicola (1.98%); and six others are classified as Lasiodiplodia sp. (5.94%). There were only slight morphological differences in colonies and conidia of these four species of Lasiodiplodia. The pathogenicity tests showed symptoms of SER, and 92.08% of the isolates exhibited a high level of virulence on avocado (disease index >70), related to the disease severity on avocado fruits. All tested isolates grew well under the temperature ranging from 23 to 33°C. There was a significant difference in mycelial growth between the four species of Lasiodiplodia after treatment with high or low temperatures. The growth of L. pseudotheobromae was the fastest at 13 to 18°C but was the lowest at 38°C (P < 0.05). The red pigment could be produced by all tested isolates after culturing for 7 days at 38°C. The mycelial growth rate was the fastest on PDA medium, and the slowest on the OMA medium but promoted spore formation (P < 0.05). In addition, the genetic diversity of pathogenic Lasiodiplodia species associated with SER collected from avocado, mango, guava, and soursop fruits was determined. A total of 74 isolates were clustered into four main ISSR groups by the unweighted pair-group method with arithmetic mean analysis, and the classification of this group was related to the host. Extensive diversity was detected in the Lasiodiplodia populations. The diverse geographical origins and host species significantly influenced the population differentiation, and most of the genetic variation occurred within populations (P < 0.001). This is the first study to identify the major pathogens of avocado SER in China, survey their occurrence and pathogenicity, and include a comparative analysis of genetic diversity with Lasiodiplodia spp. causing SER on other fruit hosts. Collectively, the Lasiodiplodia species complex affecting avocado showed high pathogenicity and diversity, while L. pseudotheobromae was the most frequently isolated species in China. The results of this study provide insights into the aspects of the epidemic of SER disease caused by Lasiodiplodia species, which will help in developing strategies for the management and control of SER in avocado.

Survey on Latent Infection of Canker-Causing Pathogens in Budwood and Young Trees from Almond and Prune Nurseries in California.

Almond band canker and prune Cytospora canker have become more severe in the last decade, especially in young orchards, in California. To test our hypothesis that young trees from nurseries could carry the canker-causing pathogens at latency phase to new orchards through transplanting, a multiyear survey on latent infection of canker-causing pathogens of budwood and young trees of almond and prune nurseries in California was conducted. A total of more than 1,730 samples including shoots of rootstocks and scions and grafting union cuttings were collected from 11 nurseries. A real-time quantitative PCR assay was applied to quantify the latent infection levels by six canker-causing pathogen taxa: Botryosphaeria dothidea and species of Cytospora, Diplodia, Lasiodiplodia, Neofusicoccum, and Phomopsis. For almond, the average incidences of latent infection caused by Lasiodiplodia spp. (43.6%) and Neofusicoccum spp. (24.2%) were significantly greater than those by the other four pathogen taxa. The molecular severity (MS) of latent infection caused by Neofusicoccum spp. (3.6) was significantly greater than those caused by other pathogen taxa, except for Lasiodiplodia spp. (2.6). For prune, the average incidence of latent infection caused by Cytospora spp. (13.5%) was significantly higher than those caused by B. dothidea (1.5%) and Diplodia spp. (1.3%) but not significantly higher than those caused by Lasiodiplodia spp. (6.9%), Neofusicoccum spp. (6.3%), and Phomopsis spp. (7.7%), respectively. Moreover, the average MS values caused by Cytospora spp. (3.8) and Neofusicoccum spp. (3.2) were the highest followed by those caused by B. dothidea (1.4), Lasiodiplodia spp. (2.2), and Phomopsis spp. (2.3). Different almond varieties showed various levels of susceptibilities to different canker-causing pathogens. This study concluded that Lasiodiplodia and Neofusicoccum are the predominant pathogen species in almond, and Cytospora is the most important canker-causing pathogen species in prune in nurseries. These findings confirmed the observations of predominancy of canker-causing pathogens in almond and prune orchards in California.

Characterization of Lasiodiplodia theobromae (Pat.) Griffon &amp; Maubl causing stem canker on Teak (Tectona grandis L.) in Ecuador

AbstractTeak is a very important tropical timber in Ecuador. In 2017, teak samples displaying stem canker symptoms were collected in two provinces of Ecuador. From 11 symptomatic trees, 11 isolates resembling a species of Lasiodiplodia were obtained. All isolates obtained induced stem canker on teak plants after artificial inoculation, confirming them as the cause of the observed canker symptoms. Bayesian inference with concatenated sequences of complete ITS and partial TEF‐α and β‐TUB gene sequences from two representative isolates clustered teak isolates with other sequences of Lasiodiplodia theobromae available in Genbank. This is the first report of L. theobromae causing stem canker on teak plants in Ecuador.

Identification of Lasiodiplodia species inciting stem rot of dragon fruit in India through polyphasic approach.

Lasiodiplodia species commonly thrive as endophytes, saprobes, and plant pathogens in tropical and subtropical regions. Association of Lasiodiplodia species causing stem rot in dragon fruit in the coastal belt of Odisha, eastern India, has been illustrated here. The stem rot disease was characterized by yellowing of the stem, followed by softening of the stem tissues with fungal fructifications of the pathogen in the affected tissues. On the basis of macro- and micromorphological characteristics, the four fungal isolates recovered from diseased stems were identified initially as Lasiodiplodia species. By comparing DNA sequences within the NCBI GenBank database as well as performing a multigene phylogenetic analysis involving the internal transcribed spacer region (ITS-rDNA), β-tubulin (β-tub), and elongation factor-alpha (EF1-α) genes, the identity of Lasiodiplodia isolates was determined. The isolate CHES-21-DFCA was identified as Lasiodiplodia iraniensis (syn: L. iranensis) and the remaining three isolates, namely CHES-22-DFCA-1, CHES-22-DFCA-2, and CHES-22-DFCA-3, as L. theobromae. Although pathogenicity studies confirmed both L. iraniensisand L. theobromae were responsible for stem rot in dragon fruit, L. iraniensis was more virulent than L. theobromae. This study established the association of Lasiodiplodia species with stem rot in dragon fruit using a polyphasic approach. Further investigations are required, particularly related to on host-pathogen-weather interaction and spatiotemporal distribution across the major dragon fruit-growing areas of the country to formulate prospective disease management strategies. This is the first report on these two species of Lasiodiplodia inflicting stem rot in Hylocereus species in India.

Two Novel Lasiodiplodia Species from Blighted Stems of Acer truncatum and Cotinus coggygria in China.

Simple SummaryLasiodiplodia species are plurivorous plant pathogens found worldwide, especially in tropical and subtropical regions, that result in fruit and root rot, die-back of branches and stem canker, etc. During the exploration of the fungal diversity of blighted stem samples collected in northern China, two new Lasiodiplodia species, L. acerina G.H. Qiao & W.T. Qin and L. cotini G.H. Qiao & W.T. Qin, were discovered based on integrated studies of phenotypic features, culture characteristics and molecular analyses. They were described and illustrated in detail. This work provided a better understanding of the biodiversity, phylogeny and established concepts of the genus Lasiodiplodia.The Lasiodiplodia are major pathogens or endophytes living on a wide range of plant hosts in tropical and subtropical regions, which can cause stem canker, shoot blight, and rotting of fruits and roots. During an exploration of the stem diseases on Acer truncatum and Cotinus coggygria in northern China, two novel species of Lasiodiplodia, L. acerina G.H. Qiao & W.T. Qin and L. cotini G.H. Qiao & W.T. Qin, were discovered based on integrated studies of the morphological characteristics and phylogenetic analyses of the internal transcribed spacer region (ITS), translation elongation factor 1-α (TEF1-α), beta-tubulin (TUB2) and RNA polymerase II subunit b genes (RPB2). Lasiodiplodia acerina is a sister taxon of L. henannica and distinguishable by smaller paraphysis and larger conidiomata. Lasiodiplodia cotini is closely related to L. citricola but differs in the sequence data and the size of paraphyses. Distinctions between the two novel species and their close relatives were compared and discussed in details. This study updates the knowledge of species diversity of the genus Lasiodiplodia. Furthermore, this is the first report of Lasiodiplodia associated with blighted stems of A. truncatum and C. coggygria in China.

Response of Different Grapevine Cultivars to Infection by Lasiodiplodia theobromae and Lasiodiplodia mediterranea.

Botryosphaeria dieback is a grapevine trunk disease that affects all viticulture regions of the world. Species of the genus Lasiodiplodia have been reported as pathogenic toward grapevine in several growing regions and have also been previously reported from Portuguese vineyards. Species in this genus, particularly Lasiodiplodia theobromae, have been reported in previous studies to be more aggressive than other Botryosphaeriaceae species most commonly associated with Botryosphaeria dieback. The aim of this study was to assess the response of some of the more representative cultivars planted throughout Portuguese vineyards, 'Touriga Nacional,' 'Touriga Franca,' 'Alvarinho,' 'Aragonez' (= 'Tempranillo'), and 'Cabernet Sauvignon,' by performing artificial inoculations with Lasiodiplodia spp. collected in different geographic locations worldwide. Two experiments, one that involved inoculating 2-year-old grapevines kept in greenhouse-controlled conditions with six isolates of L. theobromae and one isolate of L. mediterranea and one that involved inoculating 7-year-old field-grown grapevines with two isolates of L. theobromae, were conducted twice. We assessed the response of the cultivars by evaluating the length of lesions caused by the isolates 5 months after inoculation. The results showed that all isolates studied were able to infect the annual shoots because they were always reisolated and produced internal wood discoloration. Significant differences were found for all isolate-cultivar combinations. In both experiments, Touriga Nacional showed the largest lesions and while Aragonez recorded the smallest lesions of the cultivars inoculated with Lasiodiplodia spp. In general, Portuguese isolates were more aggressive than those from Peru, which were mildly aggressive. These results are a first insight into the response of selected Portuguese cultivars to Lasiodiplodia species, which are present in Portugal but not commonly associated with Botryosphaeria dieback. This research contributes to our knowledge of the impact that Botryosphaeria dieback causal agents have on crucial national cultivars, which may help winegrowers not only manage current cultural practices but also optimize decision making when planning new vineyards.

Botryosphaeriaceae diversity on Eucalyptus clones in different climate zones of Indonesia

AbstractThe Botryosphaeriaceae is an important and diverse family of latent fungal pathogens of woody plants, including Eucalyptus. These fungi live within infected plant tissues for extended periods without causing symptoms, but emerge to cause severe disease when their hosts are subjected to stress. In this study, we compared the diversity of the Botryosphaeriaceae in samples from nine different Eucalyptus clones growing in North and Central Sumatra, Indonesia, having distinct climates. Samples were taken from asymptomatic trees as well as those damaged by a sucking insect (Helopeltis sp.: Miridae), a stem boring moth (Polyphagozerra coffeae: Cossidae) and a Eucalyptus scab and shoot malformation fungal disease caused by Elsinoe necatrix. In total, 215 Botryosphaeriaceae isolates were obtained from which 13 species were identified based on rDNA‐ITS, TEF‐1α, β‐tubulin and rpb2 sequence data. These species included seven Lasiodiplodia species, four Neofusicoccum species as well as Endomelanconiopsis endophytica and Cophinforma atrovirens. A new species of Lasiodiplodia arose from collections and for which the name L. riauensis is provided. Two species, L. theobromae and L. brasiliensis, were found in both climatic zones, whereas other species were specific to the areas from which they were collected. No correlation was found between the Botryosphaeriaceae species diversity and damage to trees caused by insects or E. necatrix disease.

DIVERSITY OF ENDOPHYTIC FUNGI ASSOCIATED WITH FRUITS AND LEAVES OF TAMARIND (Tamarindusindica L.) BASED O N ITS RIBOSOMAL DNA SEQUENCES

Plant-associated microbes are among the important natural resources that abundantly exist in natural environment such as endophytic fungi. The studies on endophytic fungi in medicinal plants have allowed the discovery of numerous fungi species and their hidden potentials. Therefore, this study focused on the isolation and identification of endophytic fungi from several plant parts of tamarind such as leaves and fruits. A total of 69 fungal cultures were successfully isolated and identified into 33 distinct species from 14 genera based on morphological characteristics and internal transcribed spacer (ITS) sequence analysis using a Maximum Likelihood method. There were six different species obtained from the genus Colletotrichum (C. aenigma, C. brevisporum, C. cobbittiense, C. fructicola, C. gloeosporioides and C. siamense), and Diaporthe (D. arecae, D. ceratozamiae, D. phaseolorum, D. pseudomangiferae, D. pseudooculi and D. pseudophoenicicola), four species of Aspergillus (A. aculeatus, A. carbonarius, A. flavus and A. tubingensis), three species of Curvularia (C. aeria , C. geniculata and C. lunata) and Nigrospora (N. lacticolonia, N. oryzae and N. sphaerica), two species of Lasiodiplodia (L. pseudotheobromae and L. theobromae) and Penicillium (P. rolfsii and P. verruculosum). Other fungal species that were also identified are Botryosphaeria mamane, Fusarium solani, Perenniporia tephropora, Phyllosticta fallopiae, Sarcostroma bisetulatum, Trichoderma asperellum and Xylaria feejeensis. The isolates were grouped into different clades according to their class. In conclusion, endophytic fungi isolated from tamarind plant are diverse and provides an insight into species diversity of endophytic fungi in tamarind.

Limited Evidence for Accumulation of Latent Infections of Canker-Causing Pathogens in Shoots of Stone Fruit and Nut Crops in California.

Prevalence of latent infections of the canker-causing fungi Botryosphaeria dothidea and species of Cytospora, Diplodia, Lasiodiplodia, Neofusicoccum, and Phomopsis in young shoots of almond, prune, and walnut trees in California was studied to test the hypotheses that latent infections accumulate from current-season shoots to 1-year-old shoots in the orchard and there are distinct associations among pathogen taxa present as latent infections in the same shoot. Samples of newly emerged and 1-year-old shoots were periodically collected in each almond, prune, and walnut orchard for two growing seasons. A real-time quantitative PCR assay was used to quantify latent infection with three parameters: incidence, molecular severity, and latent infection index. Diplodia spp. were absent from most samples. For almond, Lasiodiplodia spp. and Cytospora spp. were detected with a maximum incidence >90%, while B. dothidea and Neofusicoccum spp. incidence was <20% in most cases. In prune orchards, the incidence levels of B. dothidea were >50% in most cases, while those of Cytospora spp. and Lasiodiplodia spp. were 30 to 60% and 30 to 100%, respectively. For walnut, many samplings showed higher incidence in 1-year-old (30 to 80%) than in newly emerged shoots (10 to 50%). Accumulation of latent infection between the two shoot age classes was detected in only a few cases. The percentages of samples showing coexistence of two, three, and four pathogen taxa in the same shoot were 20 to 25, <10, and <5%, respectively. Pairwise associations among pathogen taxa in the same shoot were significant in many cases.

Antifungal activity of crude extracts of Ageratum conyzoides and Chromolaena odorata for management of Lasiodiplodia theobromae and Lasiodiplodia pseudotheobromae through in vitro evaluation

Lasiodiplodia is an important genus of fungi causing destructive diseases on perennial crops, including cocoa. Two crucial species of Lasiodiplodia that cause diseases in cocoa are Lasiodiplodia theobromae and Lasiodiplodia pseutheobromae. A variety of weeds is the potential to be applied as botanical fungicides to control the pathogens. The main objective of this study was to evaluate Ageratum conyzoides and Chromolaena odorata leaf extract to inhibit the growth of L. theobromae and L. pseudotheobromae on a synthetic medium. Solvent organic was methanol for weed extraction with a ratio of 1:5. The experiment was conducted through the poison food technique method, both in the solid and liquid medium in three different concentrations, 1, 3, and 5%. The result showed that A. conyzoides and C. odorata were significantly inhibited the colony growth of both Lasiodiplodia in all concentrations in a solid medium. A. conyzoides performed better than C. odorata in all concentrations of both Lasiodiplodia in inhibition. A. conyzoides 5% performed well to suppress the colony growth of L. pseudotheobromae (100%), followed by A. conyzoides 3% and A. conyzoides 1%. A. conyzoides 5% able to inhibit the colony growth of L. theobromae until 100%, followed by A. conyzoides 3% and 1%. Meanwhile, A. conyzoides and C. odorata extract tested on PDB medium at 1, 3, and 5% reduced the fungal biomass significantly at all concentrations. C. odorata was found most effective in inhibiting fungal biomass of both pathogens either on wet weight or on dry weight at 1, 3, and 5% %. A. conyzoides and C. odorata can manage the growth of L. theobromae and L. pseudotheobromae through in vitro conditions.

Multigene Phylogenetics and Morphology Reveal Five Novel Lasiodiplodia Species Associated with Blueberries.

Botryosphaeriaceous fungi cause stem blight, canker and dieback in woody plants. During a survey on the fungal pathogens associated with blueberries in China, 135 blighted, cankered or dead blueberry branches were collected from Fujian and Shandong Provinces. Based on the morphological characterization and phylogenetic analyses of a concatenated ITS rDNA, tef1-α, TUB, and RPB2 loci, five new species of Lasiodiplodia, viz., L. clavispora, L. fujianensis, L. henanica, L. nanpingensis and L. paraphysoides were recognized. Detailed descriptions and illustrations, as well as multigene phylogenies, are provided in this paper. The diversity of plant pathogens on agriculturally and economically important plants is higher than anticipated.

Morpho-phylogenetic evidence reveals Lasiodiplodia chiangraiensis sp. nov. (Botryosphaeriaceae) associated with woody hosts in northern Thailand

Lasiodiplodia species are commonly as endophytes, saprobes and pathogens in tropics and subtropics. During an investigation of Botryosphaeriaceae in Thailand, two Lasiodiplodia taxa were isolated. Morphological characteristics and phylogenetic analyses based on combined ITS, tef and tub2 sequence data support the establishment of a novel species, Lasiodiplodia chiangraiensis, isolated from woody hosts. Lasiodiplodia chiangraiensis is phylogenetically close to L. iraniensis and L. thailandica, but represents a distinct lineage. The new species could be distinguished from extant Lasiodiplodia species by its mature conidial dimensions. A detailed description and illustration are provided, as well as an updated phylogenetic tree (ITS, tef and tub2) including all species (with available molecular data) of Lasiodiplodia. In addition, the accepted genera in Botryosphaeriaceae based on recent studies are given.

First report of Berkeleyomyces basicola causing mango root rot and decline in India.

Mango wilt has been a serious constraint in mango (Mangifera indica L.) production in several countries including India (Shukla et al. 2018). Although, several fungal pathogens have been reported associated with the disease, species of Ceratocystis, Verticillium and Lasiodiplodia have been found predominantly responsible for the wilt (Shukla et al. 2018). A twenty-seven-year old mango tree cv. Dashehari at Rehmankhera, Lucknow, Uttar Pradesh, India suffered sudden wilt (Fig. 1A) during February 2020. Though, symptoms were similar to Ceratocystis wilt, no gummosis was observed on trunk or branches which occurred in the majority of Ceratocystis fimbriata infected trees. The infected roots of the wilted tree exhibited dark brown to black discoloration in woody portions (Fig. 1B). Severely affected roots were completely rotten. Similar symptoms of root infection were observed in an additional 16 declining trees within an orchard of 120 trees total (Fig. 2). The infected hard wood samples from live roots of 16 declining and one wilted trees were utilized for isolation by placing stem tissue of discolored and normal colored tissue on surface sterilized fresh carrot discs placed in a moisture chamber (Fig. 1C) for 10 days. Out of 17 tree samples, isolates of Berkeleyomyces basicola (Berk. & Broome) W.J. Nel, Z.W. de Beer, T.A. Duong, M.J. Wingf. (Nel et al. 2018) obtained from 1 wilted and 9 declining trees were transferred to and maintained in pure culture on potato dextrose agar. Isolates were grown for 7 to 10 days at 23±1 °C temperature in the dark. The isolates were characterized by a greyish black compact mycelial colony (Fig. 1D). Two types of spores, endoconidia (phialospores) and chlamydospores (aleuriospores or amylospores) were observed under microscope. The endoconidia were hyaline, cylindrical in shape with 10 to 42 × 3 to 6 μm (n=50) in size (Fig. 1E). Chains of dark colored chlamydospores (3 to 7 spores in chain) of 24 to 52 × 10 to 12 μm (n=50) size were apparent (Fig. 1E&F). Molecular identification of the fungus isolated from the wilted tree was established by amplifying the ITS1-5.8 rDNA-ITS2 region of fungal genomic DNA and the set of ITS primers (ITS 1 and ITS4) (White et al. 1990) followed by sequencing. The sequence has been submitted to the NCBI database vide accession number MT786402. The present isolate (MT786402) shared >99 percent nucleotide similarity with other B. basicola isolates. The phylogenetic tree was constructed using the ITS1-5.8 rDNA-ITS2 sequences of other B. basicola isolates and other Thielaviopsis spp., C. fimbriata, Chalaropsis thielavioides through neighbor joining method using MEGAX software (Fig. 3) (Kumar et al. 2018). The present isolate formed a distinct cluster along with other B. basicola isolates in a separate clade. Koch's postulate was performed under a transparent polycarbonate sheet roof net house at 14.4 and 42.2 °C minimum and maximum temperatures, respectively. A 100 ml macerated culture suspension consisting of 1000 chlamydospores and endoconidia per ml suspension was inoculated in the rhizosphere of mango seedlings planted in sterilized soil filled in earthen pots, using ten replicates for inoculated and uninoculated plants. Symptoms of necrotic root tissue were observed 90 days after inoculation and were consistent with those observed in the field. The same fungus was re-isolated from infected roots and identity was confirmed. All control plants remained symptom-free and B. basicola was not isolated from the roots. Thus, we conclude that B. basicola is capable of causing root rot disease of mango. To the best of our knowledge this is the first report of B. basicola causing mango root rot and decline across the globe, hitherto unreported. The extent of the root necrosis symptoms associated with mature mango trees demonstrates the potential virulence of B. basicola, although its pathogenicity risk on healthy mature trees is still unknown. However, the possibility of severe losses to the mango industry in world number one mango producer country, India cannot be ruled out, if found widespread.

In vitro efficacy of some plant aqueous extracts against two species of Lasiodiplodia associated to mango decline in Burkina Faso

Mango decline is a serious disease in production areas in Burkina Faso. The aim of this study was to contribute to the management of the disease through the use of plant aqueous extracts. Antifungal activities of Azadirachta indica, Calotropis procera, Gmelina arborea, Jatropha curcas, Eucalyptus camaldulensis and the synthetic fungicide (Mancozeb) were tested against Lasiodiplodia theobromae and Lasiodiplodia pseudotheobromae associated to mango decline in Burkina Faso. Three different concentrations of leaf extracts which 25%, 50%, 75% and 500 ppm of Mancozeb were tested for their antifungal activity in vitro. The results showed that leaf extracts have an inhibitor effect on the growth of the two Lasiodiplodia species. The aqueous extract of G. arborea was the most effective with average inhibition rates of L. theobromae of 42.62%, 73.84% and 74.23% respectively with the concentrations of 25 g/l, 50 g/l and 75 g/l. The aqueous extract of A. indica against L. pseudotheobromae showed maximum percentage inhibition with 50 g/l of 63.10% and with 75 g/l of 72.02%. Mancozeb completely inhibits the mycelial growth of both species of fungi. Ours findings showed that aqueous extracts from plants could be tried for the eco-friendly management of mango decline pathogens.Keywords: Antifungal, plants extract, Lasiodiplodia spp., mango decline, Burkina Faso.

Identification of Botryosphaeriaceae associated with stem-end rot of mango (Mangifera indica L.) in Malaysia.

To identify Botryosphaeriaceae fungal species that are associated with stem-end rot of mango, and to study their pathogenicity on mango fruit. Based on the sequences of internal transcribed spacer (ITS), TEF1-α and β-tubulin, as well as on the phylogenetic analysis of combined sequences, four species of Lasiodiplodia (L. theobromae,L. pseudotheobromae, L. iranensis, L. mahajangana) and two species of Neofusicoccum (N. ribis, N. parvum) were identified. Pseudofusicoccum violaceum, Neoscytalidium dimidiatum and three species of Botryosphaeria (B. scharifii, B. dothidea, B. ramosa) were identified based on sequences of ITS and TEF1-α. Pathogenicity test of selected isolates were tested on Chok Anan, Waterlily and Falan mango cultivars. Generally, all species were observed to be pathogenic on the three tested mango cultivars on wounded fruits, except for N. ribis and N. parvum, which were pathogenic on both wounded and unwounded fruits. However, N. ribis was only pathogenic on cultivar Falan, whereas B. ramosa were pathogenic on cultivars Waterlily and Falan. Eleven species of Botryosphaeriaceae were associated with mango stem-end rot in Malaysia. To the best of our knowledge, four species, namely L. mahajangana, B. ramosa, N. ribis and P. violaceum are the first recorded Botryosphaeriaceae fungi associated with stem end rot of mango. The identification of Botryosphaeriaceae fungi is important to establish suitable control measures and quarantine requirements. Many species have a wide host range, which means that there is a possibility of cross infection from other infected plants.

First Report of Lasiodiplodia theobromae Causing Stem Canker of Fraxinus americana

First Report of <i>Lasiodiplodia theobromae</i> Causing Stem Canker of <i>Fraxinus americana</i>

Phylogeny and morphology of Lasiodiplodia species associated with Magnolia forest plants

Two new species of Lasiodiplodia (Lasiodiplodia endophytica and Lasiodiplodia magnoliae) are described and illustrated from Magnolia forests in Yunnan, China. Endophytic and saprobic Lasiodiplodia pseudotheobromae and endophytic L. thailandica are new records from this host. The internal transcribed spacers (ITS), part of the translation elongation factor-1α (tef1) and partial β-tubulin (tub2) sequence data were analyzed to investigate the phylogenetic relationships of the new species with other Lasiodiplodia species. Lasiodiplodia magnoliae is phylogenetically sister to L. mahajangana and L. pandanicola but morphologically distinct from L. mahajangana in having larger conidia. Lasiodiplodia endophytica is most closely related to L. iraniensis and L. thailandica and the three species can be distinguished from one another by 2 base pair differences in ITS and three or four base pair differences in tef1. The new collections suggest that Magnolia forest plants are good hosts for Lasiodiplodia species with endophytic and saprobic life-styles.