Occurrence of branch dieback and decline of mangoes in Derby North - - PowerPoint PPT Presentation

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Occurrence of branch dieback and decline of mangoes in Derby North - - PowerPoint PPT Presentation

Oct 15, 2022 8 likes •172 views

Occurrence of branch dieback and decline of mangoes in Derby North Western Australia. Symptom of a branch dieback on Kensington cultivar Pycnidial structures formed on the infected branches. Morphological characteristics of the isolated fun gi

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Occurrence of branch dieback and decline of mangoes in Derby North Western Australia.

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Symptom of a branch dieback on Kensington cultivar

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Pycnidial structures formed on the infected branches.

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Morphological characteristics of the isolated fungi

Lasiodiplodia theobromae

 Pycnidia; simple or compound, often aggregated,

stromatic, ostiolate, up to 2 mm wide.

 Conidia; 24-30×12-16µm, hyaline and aseptate,

becoming dark brown and one-septate. Pseudofusicoccum adansoniae

 Pycnidia; 500 µm submerse and solitaries.  Conidia; 20-24×4.5-6 µm, ellipsoid straight or slightly

curved, hyaline thin walled forming 1-2 septa. Neoscytalidium novaehollandiae

 Pycnidia; 300 µm semi-immersed or superficial,

solitary or in multilocular black with long neck

 Conidia;

1) 10.5-14×3.5-5 µm first hyaline becoming cinnamons in color and 0 to 1 septa 2) 8.5-12×5.5-7 µm variable in shape globose to

  • bpyriform
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Pseudofusicoccum adansoniae; conidiogenous cells, conidiophores and conidia. Bars 10µm

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Lasiodiplodia theobromae; conidiogenous cells, conidiophores and conidia. Bars 10µm

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Neoscytalidium novaehollandiae; conidiogenous cells, conidiophores and conidia. Bars 10µm

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Phylogram of the most parsimonious trees obtained from the ITS sequence data

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Mean lesion length (mm) on excised branches of mango inoculated with isolates of P. adansonia (WAC13373), L. theobromae (WAC13374) and N. novaehollandiae (WAC13375). (P = 0.05)

5 10 15 20 25 30 W A C 1 3 3 7 4 W A C 1 3 3 7 3 W A C 1 3 3 7 5 C

  • n

t r

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Botryosphaeria species Mean lesion lenght (mm)

Lsd

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CONCLUSION

Lasiodiplodia theobromae, Pseudofusicoccum adansoniae and Neoscytalidium novaehollandiae are components of dieback and decline of the mango trees in Derby. Lasiodiplodia theobromae and Neoscytalidium novaehollandiae are highly pathogenic in comparison to Pseudofusicoccum adansoniae. Botryosphaeria species are endophytes and

  • pportunistic pathogens, on the trees experiencing

stress, Further investigation is needed to identify stress related factors in mango orchards.

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ACKNOWLEDGMENTS

I would like to thank Cuiping Wang and Paula Mather for their technical assistance.