Mango Dieback Research Articles

Identification and Characterization Colletotrichum spp. Causing Mango Dieback in Indonesia.

Dieback disease in mango trees has been observed in Indonesia, particularly in Java Island, with the causal agent remaining unidentified. One of the important pathogens that are responsible for causing mango dieback is Colletotrichum. Field surveys were conducted in various mango cultivating areas in Java Island, Indonesia to assess prevalence of Colletotrichum as dieback disease pathogen. Eleven Colletotrichum isolates were recovered from symptomatic dieback twigs and morphologically characterized. Genetic diversity fingerprint analysis was carried out using rep-PCR. Phylogenetic analysis identified isolates as belonging to Colletotrichum asianum and Colletotrichum cairnsense using partial sequences of four gene regions, including ITS, ACT, GAPDH, and TUB2. Pathogenicity tests on mango seedlings cv. Arumanis showed that all fungal isolates were responsible for causing dieback symptoms. Subsequently, symptomatic tissue was reisolated to fulfill Koch's Postulate. This study represented new funding for two species of Colletotrichum causing mango dieback in Indonesia.

In vitro Evaluation of Antagonistic Effect of Bio Control Agents (BCA) against Mango Dieback Incited by Lasiodiplodia theobromae (Pat.) Griffon & Maubl

Mango (Mangifera indica L.) is one of the most important tropical fruit crops, belongs to family anacardiaceae. Mango is infected by number of diseases at all stages of its development, among them dieback caused by Lasiodiplodia theobromae (Pat.) Griffon & Maubl. is considered to be the most destructive disease, leading to significant yield loss and low fruit quality of mango due to slowly wilting of tree. The present investigation was carried out to evaluate the inhibitory activity of different bio-control agents (BCA) against L. theobromae. Different bioagents viz., Trichoderma viride NAU isolate, T. harzianum, NAU isolate, Pseudomonas fluorescens NAU isolate, Bacillus subtilis NAU isolate and Rhizospheric actinobacteria were tested by dual culture technique. Among them, highest per cent growth inhibition was found in T. viride (71.47%) followed by T. harzianum (67.15%) and rhizospheric actinobacteria (47.84%). P. fluorescens (3.46%) was found least effective against pathogen. The results indicated that among all the BCA, T. viride was most effective against L. theobromae. Hence, it can be explored further for management of mango dieback.

Dieback of Mango and Cutting Method Impact on the Regeneration of Tree in the Sudano-Sahelian Zone

Dieback of Mango and Cutting Method Impact on the Regeneration of Tree in the Sudano-Sahelian Zone

Coinfection and in vitro interaction of Lasiodiplodia pseudotheobromae and Pestalotiopsis mangiferae associated with dieback in branches of mango (Mangifera indica) Manila variety, in Veracruz, Mexico

<p>Dieback disease caused by fungal complexes is a severe problem in mango trees (<em>Mangifera indica</em>). Its main symptoms are branch rot, gummosis, and finally, the tree’s death. In this work, the species of the fungal complex causing mango dieback in the Manila variety in Veracruz, Mexico were identified. The <em>in vitro </em>interaction of two species belonging to the complex was evaluated and the severity of the co-infection in mango branches. <em>Lasiodiplodia pseudotheobromae </em>and <em>Pestalotiopsis mangiferae </em>were identified as causal agents of mango dieback in the producing area of Veracruz. In coinfected mango branches, greater severity of necrosis was observed than in individual infections. Liquid culture filtrates applied in co-cultures showed different results for each species of phytopathogen. The <em>P. mangiferae </em>filtrate had no significant antagonistic effects on the growth of <em>L. pseudotheobromae </em>(inhibition of 2.68%), while the <em>L. pseudotheobromae </em>filtrate inhibited 41.38% of <em>P. mangiferae</em>. The results show that multiple infections in mango trees increase the damage caused by dieback, which could directly impact the development of control strategies.</p>

Neofusicoccum batangarum Causing Dieback of Mango (Mangifera indica) in Florida

Mango (Mangifera indica) is an economically significant crop, and is affected by dieback in nearly all commercial production areas. Due to the wide range of organisms previously associated with these disease symptoms in Florida, isolations and pathogenicity tests were carried out to determine the causal organism. The pathogen was identified as Neofusicoccum batangarum based on genetic sequences from three loci (internal transcribed spacer of the rDNA (ITS), β-tubulin (BT), and translation elongation factor 1-α (EF)), recommended for members of the Botryosphaeriaceae family. Possible infection routes were determined by inoculating wounded and unwounded stems with N. batangarum. Trees wounded prior to pathogen inoculation developed larger lesions (5.85 cm ± 1.51) than unwounded trees (0.51 cm ± 0.48), p < 0.0003. In addition, lesions only developed at a small number of inoculation sites in the absence of wounds (14.3%), compared to 93% when stems were wounded. No necrosis was observed in the negative controls. This study provides molecular data on N. batangarum, and evidence of its role causing mango dieback in Florida.

Evaluation of fungicides against Botryodiplodia theobromae - The incitant of mango dieback and gummosis

Evaluation of fungicides against Botryodiplodia theobromae - The incitant of mango dieback and gummosis

Variability of mango accessions resistance to dieback disease caused by Lasiodiplodia theobromae and Neofusicoccum parvum

Mango growing is one of the main agricultural activities in the fruit sector in Brazil for the internal and export market. The crop is subject to damage caused by the fungi Lasiodiplodia theobromae and Neofusicoccum parvum, especially mango dieback disease, which limits the yield and longevity of the mango tree. In spite of the importance of these pathogens, studies regarding sources of resistance in mango are rare. The aim of this study was to evaluate 75 accessions of mango available in the germplasm bank regarding resistance to the fungi L. theobromae and N. parvum to support breeding programs for mango growing. Evaluations were carried out from Apr 2016 to Mar 2018. Conidia suspensions of 104 conidia mL-1 of L. theobromae or N. parvum were applied with a manual sprayer on young branches. Accessions were considered resistant when disease symptoms were absent on more than 90% of the branches at three different periods of inoculation. Thirty-three accessions showed resistance to L. theobromae and 19 accessions showed resistance to N. parvum. Six accessions were most susceptible (<50%) to L. theobromae, whereas 25 accessions were most susceptible to N. parvum. The accessions ‘Apple DCG’, ‘Ataulfo’, ‘Da porta’, ‘Dashehari’, ‘Espada’, ‘Haden’, ‘Haden 2H’, ‘Heidi’, ‘Irwin’, ‘Keitt’, ‘Kent’, ‘Neldica’, ‘Recife’, and ‘Smith’ showed resistance to the two pathogens and can be used as sources of resistance to the two fungi in mango breeding studies, or these accessions can even be recommended for use as commercial cultivars.

Biological Control of Mango Dieback Disease Caused by Lasiodiplodia theobromae Using Streptomycete and Non-streptomycete Actinobacteria in the United Arab Emirates.

Dieback caused by the fungus Lasiodiplodia theobromae is an important disease on mango plantations in the United Arab Emirates (UAE). In this study, 53 actinobacterial isolates were obtained from mango rhizosphere soil in the UAE, of which 35 (66%) were classified as streptomycetes (SA) and 18 (34%) as non-streptomycetes (NSA). Among these isolates, 19 (12 SA and 7 NSA) showed antagonistic activities against L. theobromae associated with either the production of diffusible antifungal metabolites, extracellular cell-wall-degrading enzymes (CWDEs), or both. Using a “novel” mango fruit bioassay, all isolates were screened in vivo for their abilities to reduce lesion severity on fruits inoculated with L. theobromae. Three isolates, two belonging to Streptomyces and one to Micromonospora spp., showed the strongest inhibitory effect against this pathogen in vitro and were therefore selected for tests on mango seedlings. Our results revealed that the antifungal action of S. samsunensis UAE1 was related to antibiosis, and the production of CWDEs (i.e., chitinase) and siderophores; whilst S. cavourensis UAE1 and M. tulbaghiae UAE1 were considered to be associated with antibiotic- and CWDE-production, respectively. Pre-inoculation in greenhouse experiments with the most promising actinobacterial isolates resulted in very high levels of disease protection in mango seedlings subsequently inoculated with the pathogen. This was evident by the dramatic reduction in the estimated disease severity indices of the mango dieback of individual biocontrol agent (BCA) applications compared with the pathogen alone, confirming their potential in the management of mango dieback disease. L. theobromae-infected mango seedlings treated with S. samsunensis showed significantly reduced number of defoliated leaves and conidia counts of L. theobromae by 2- and 4-fold, respectively, in comparison to the other two BCA applications. This indicates that the synergistic antifungal effects of S. samsunensis using multiple modes of action retarded the in planta invasion of L. theobromae. This is the first report of BCA effects against L. theobromae on mango seedlings by microbial antagonists. It is also the first report of actinobacteria naturally existing in the soils of the UAE or elsewhere that show the ability to suppress the mango dieback disease.

Characterization and evaluation of fungicide resistance among Lasiodiplodia theobromae isolates associated with mango dieback in Oman

Dieback is one of the most common diseases of mango in different parts of the world, including Oman. Despite efforts to control the disease using different fungicides, disease incidence is still high in some farms in the country. This study involved in-depth analysis of the causal agents of the disease in two farms in Oman and the degree of sensitivity of fungal isolates to four common fungicides. The survey showed the association of dieback symptoms with 100% of mango cultivars in the first farm and 47% of mango cultivars in the second farm, with some cultivars having higher disease incidence (e.g. cvs Rothana and Zafran). Isolations from 40 mango trees showing dieback symptoms revealed the association of Lasiodiplodia spp. with 95% of the trees. Alternaria and Fusarium spp. were isolated from only 10% and 8% of the trees, respectively. Further identification of 67 Lasiodiplodia isolates using sequences of the internal transcribed spacer region of the ribosomal RNA gene (ITS rRNA) and sequence of the translation elongation factor gene (TEF) revealed that all isolates belong to Lasiodiplodia theobromae. Pathogenicity test of two randomly selected isolates of L. theobromae on cvs Amerbally and Omani showed that inoculated seedlings started showing dieback symptoms 2 within two weeks post inoculation. Testing sensitivity of 28 randomly selected L. theobromae isolates to four common fungicides showed that the EC50 levels of the isolates were in the range of 0.01-8.75 (avg. 0.54 mg l-1 ) for iprodione, 0.1-242.8 (111.6 mg l-1 ) for copper oxychloride, 40.3-738.1 (avg. 229.3 mg l-1 ) for copper hydroxide and 0.1 to over 1000 (avg.˃1000 mg l-1 ) for thiophanate-methyl. The current study showed the development of resistance to some fungicides, especially thiophanate-methyl. Development of resistance to fungicides could be one of the main reasons behind the reduction in the efficacy of managing dieback in the studied farms.

Detection and Management of Mango Dieback Disease in the United Arab Emirates.

Mango is affected by different decline disorders causing significant losses to mango growers. In the United Arab Emirates (UAE), the pathogen was isolated from all tissues sampled from diseased trees affected by Lasiodiplodia theobromae. Symptoms at early stages of the disease included general wilting appearance of mango trees, and dieback of twigs. In advanced stages, the disease symptoms were also characterized by the curling and drying of leaves, leading to complete defoliation of the tree and discolouration of vascular regions of the stems and branches. To substantially reduce the devastating impact of dieback disease on mango, the fungus was first identified based on its morphological and cultural characteristics. Target regions of 5.8S rRNA (ITS) and elongation factor 1-α (EF1-α) genes of the pathogen were amplified and sequenced. We also found that the systemic chemical fungicides, Score®, Cidely® Top, and Penthiopyrad®, significantly inhibited the mycelial growth of L. theobromae both in vitro and in the greenhouse. Cidely® Top proved to be a highly effective fungicide against L. theobromae dieback disease also under field conditions. Altogether, the morphology of the fruiting structures, molecular identification and pathogenicity tests confirm that the causal agent of the mango dieback disease in the UAE is L. theobromae.

Identification of Lasiodiplodia pseudotheobromae causing mango dieback in Korea

Mango (Mangifera indica) is an economically important fruit grown in tropical regions. Mango cultivation has increased in Korea as the fruit has become more popular; however, the majority of the fruit is imported. Mango dieback was observed for the first time in July 2016, in Tongyeong, South Korea. The aim of the present study was to identify the causal pathogen. Identification of the fungus was based on morphological and cultural characteristics, and sequencing of the internal transcribed spacer rRNA region and gene encoding translation elongation factor 1-alpha. A phylogenetic analysis of the sequences confirmed that the fungus isolated from diseased mango plants was Lasiodiplodia pseudotheobromae. Koch’s postulates were completed by pathogenicity tests conducted on healthy leaves, fruit and whole plants. Based on the morphological characteristics, pathogenicity tests, and molecular identification, the causal fungus was identified as L. pseudotheobromae. This is the first report of mango dieback caused by L. pseudotheobromae in Korea. The recent occurrence of the disease indicates that the fungus poses a potential threat to mango production in Korea.

Phylogeny and pathogenicity of Lasiodiplodia species associated with dieback of mango in Peru

Mango, which is an important tropical fruit crop in the region of Piura (Peru), is known to be prone to a range of diseases caused by Lasiodiplodia spp. The aim of this study was to evaluate the incidence and prevalence of mango dieback in the region of Piura, and to identify the species of Lasiodiplodia associated with the disease and evaluate their pathogenicity towards mango. Mango dieback was present in all orchards surveyed but incidence varied with location. Identification of fungal isolates was based on morphological and cultural characteristics as well as sequence data of the rDNA internal transcribed spacer region (ITS) and translation elongation factor 1-alpha gene (tef1-α). The following Lasiodiplodia species were identified: Lasiodiplodia brasiliense, Lasiodiplodia egyptiacae (for which the new combination Lasiodiplodia laeliocattleyae is introduced), Lasiodiplodia iraniensis, Lasiodiplodia pseudotheobromae, Lasiodiplodia theobromae, and a Lasiodiplodia sp. Individual and combined gene genealogies suggest that this Lasiodiplodia sp. is possibly a hybrid of Lasiodiplodia citricola and Lasiodiplodia parva. Apart from Lasiodiplodia theobromae, which was the most prevalent species, all other species are newly reported from Peru. Moreover, L. iraniensis is reported for the first time on mango. Inoculation trials of mango plants confirmed Koch's postulates, and revealed differences in aggressiveness among species and isolates.

Chemical and cultural management of die back disease of mango in Pakistan

Die back of mango is very destructive disease caused by Lasiodiplodia theobromae which is alarming mango growers of Pakistan with its characteristic symptoms as discoloration and darkening of twigs from tip to downward, withering, drying and defoliation. Investigations to effectively manage the disease using fungicides and other options were carried out in vitro as well as in experimental orchard of Mango Research Station Shujabad Multan, Pakistan during 2011-2012. The experimental fungicide treatments were Cobox (Copper oxychloride), Precure combi (Thiophanate methyl + dietheofenocarb) and Cabrio top (Pyraclostrobin + metiram) at four concentrations 25, 50, 75 and 100 ppm. Firstly, these chemicals were evaluated for their control of L. theobromae in vitro. Cobox (Copper oxychloride) and Precure combi (Thiophanate methyl + dietheofenocarb) showed significant reduction in colony diameter of L. theobromae at all concentrations compared to non-treated/control. Cabrio top (Pyraclostrobin + metiram) did not significant decrease the colony diameter of L. theobromae. In the field Precure combi (Thiophanate methyl + dietheofenocarb) and Cobox (Copper oxychloride) were also used as foliar, soil drenching in addition with soil amendment with silt, NPK & manure and pruning to manage the naturally affected mango plants with die back. It was found that maximum decrease in disease over control (72.92%) was noted where soil amendment and pruning was done with soil drenching of Cobox. This treatment may be included in the holistic disease management program against the die back of mango.

Emerging resistance against different fungicides in Lasiodiplodia theobromae, the cause of mango dieback in Pakistan

Dieback of mango caused by Lasiodiplodia theobromae is among several diseases responsible for low crop production in Pakistan. To further complicate the issue, resistance in L. theobromae is emerging against different fungicides. L. theobromae was isolated from diseased samples of mango plants collected from various orchards in the Multan District. The efficacy of different fungicides viz. copper oxychloride, diethofencarb, pyrachlostrobin, carbendazim, difenoconazole, mancozeb, and thiophanate-methyl was evaluated in vitro using a poison food technique. Thiophanate-methyl at all concentrations was found to be the most effective among five systemic fungicides against L. theobromae, followed by carbendazim, difenoconazole and diethofencarb. The fungicides, i.e., thiophanate-methyl, difenoconazole, carbendazim and diethofencarb showed maximum efficacy with increasing concentration. The isolates of L. theobromae showed some resistance development against the tested fungicides when compared with previous work. These investigations provide new information about chemical selection for the control of holistic disease in mango growing zones of Pakistan.

First report of Lasiodiplodia theobromae causing canker on tapped Boswellia papyrifera trees in Ethiopia

Boswellia papyrifera (Burseraceae) is found mainly in the Amhara, Tigray and Benshangul Gumze Regions of Ethiopia (Vollesen, 1989). This economically important tree species is widely used for frankincense (incense) production. Incense is…

First Report of Dieback of Mango Caused by Fusarium decemcellulare in China

AbstractDuring 2009–2011, a dieback disease of mango (Mangifera indica) has recently emerged on mango trees in Panzhihua City, Sichuan province of China. The disease is characterized by large irregular brown‐coloured speckles on the petioles and twigs, vascular necrosis and dry leaves and complete twig mortality. Fusarium species were isolated repeatedly from the infected petioles and twigs. The species was identified as Fusarium decemcellulare Brick based on morphology and sequence analysis of Translation Elongation Factor‐1alpha (TEF‐1α) gene. Koch's postulates were fulfilled by pathogenicity tests on potted mango seedlings. To our knowledge, this is the first record of dieback on mango caused by F. decemcellulare in China.

First report of Lasiodiplodia theobromae causing canker and shoot blight of fig in Turkey

There are over 10 million fig ( Ficus carica ) trees in Turkey (Anonymous, 2009). The majority of these trees are grown in the Aydin and Izmir Provinces of the Aegean region, although there are fig plantations in northern areas of Turkey as…

First Report of Mango Dieback Caused by Pseudofusicoccum stromaticum in Brazil.

From September to December 2010, mango (Mangifera indica L.) stems showing dieback symptoms were collected during a survey conducted in São Francisco Valley, northeastern Brazil. Small pieces (4 to 5 mm) of necrotic tissues were surface sterilized for 1 min in 1.5% NaOCl, washed twice with sterile distilled water, and plated onto potato dextrose agar (PDA) amended with 0.5 g liter-1 streptomycin sulfate. Plates were incubated at 25°C in the dark for 14 to 21 days and colonies that were morphologically similar to species of Botryosphaeriaceae were transferred to PDA. Colonies developed a compact mycelium that was initially white, but becoming gray dark after 4 to 6 days of incubation at 25°C in darkness. Identification was made using morphological characteristics and DNA based molecular techniques. Pycnidia were obtained on 2% water agar with sterilized pine needles as substratum after 3 weeks of incubation at 25°C under near-UV light. Pycnidia were large, multilocular, eustromatic, covered with hyphae; locule totally embedded without ostioles, locule walls consisting of a dark brown textura angularis, becoming thinner and hyaline toward the conidiogenous region. Conidia were hyaline, thin to slightly thickened walled, aseptate, with granular contents, bacilliform, straight to slightly curved, apex and base both bluntly rounded or just blunt, 15.6 to 25.0 (20.8) μm long, and 2.7 to 7.9 (5.2) μm wide, length/width = 4.00. According to these morphological characteristics, three isolates (CMM1364, CMM1365, and CMM1450) were identified as Pseudofusicoccum stromaticum (1,3,4). PCR amplification by universal primers (ITS4/ITS5) and DNA sequencing of the internal transcribed spacer (ITS1-5.8S-ITS2 rRNA gene cluster) were conducted to confirm the identifications through BLAST searches in GenBank. The isolates were 100% homologous with P. stromaticum (3) (GenBank Accession Nos. AY693974 and DQ436935). Representative sequences of the isolates were deposited in GenBank (Accession Nos. JF896432, JF966392, and JF966393). Pathogenicity tests were conducted with the P. stromaticum strains on 5-month-old mango seedlings (cv. Tommy Atkins). Mycelial plugs taken from the margin of actively growing colonies (PDA) of each isolate were applied in shallow wounds (0.4 cm in diameter) on the stem (center) of each plant. Inoculation wounds were wrapped with Parafilm. Control seedlings received sterile PDA plugs. Inoculated and control seedlings (five each) were kept in a greenhouse at 25 to 30°C. After 5 weeks, all inoculated seedlings showed leaf wilting, drying out of the branches, and necrotic lesions in the stems. No symptoms were observed in the control plants. P. stromaticum was successfully reisolated from symptomatic plants to fulfill Koch's postulates. P. stromaticum was described from Acacia, Eucalyptus, and Pinus trees in Venezuela (3,4), and there are no reports of this fungus in other hosts (2). To our knowledge, this is the first report of P. stromaticum causing mango dieback in Brazil and worldwide.

First record ofNeoscytalidium dimidiatumandN. novaehollandiaeonMangifera indicaandN. dimidiatumonFicus caricain Australia

Neoscytalidium dimidiatum is reported for the first time in Australia associated with dieback of mango and common fig. Neoscytalidium novaehollandiae is reported for the first time associated with dieback of mango.

Mango Dieback and Gummosis in Sindh, Pakistan Caused by Lasiodiplodia theobromae

Diagnosis of dieback and gummosis (caused by Lasiodiplodia theobromae (Pat.)) on mango in Sindh, Pakistan is described, including: taxonomy; symptoms and signs; host range; geographical distribution; pathogen isolation, identification, and storage; and pathogenicity tests. Accepted for publication 16 January 2004. Published 2 March 2004.