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<p>Mango twig tip dieback (MTTD) was first observed in the outer Darwin rural area, Northern Territory, in 2017. The disease is characterised by dark necrotic lesions on the twigs of mango trees that extend rapidly causing death of the apical bud, the twig dieback symptoms are also associated with general tree decline, branch death, and reduced productivity. Since its first detection in Darwin, MTTD is now widespread in commercially grown Kensington Pride mangoes and is of major concern to the mango growers in the region. In this study, fungi were isolated and identified from symptomatic and asymptomatic mango twigs. MTTD symptoms are associated with members of the Botryosphaeriaceae, namely, <i>Lasiodiplodia</i> species, <i>Neofusicoccum sinoeucalypti</i>, and <i>Neoscytalidium dimidiatum</i>. However, <i>Lasiodiplodia</i> species were isolated from 96% of the symptomatic samples. The most frequently isolated species were <i>Lasiodiplodia pseudotheobromae</i> and <i>Lasiodiplodia rubropurpurea</i>, although <i>Lasiodiplodia mahajangana</i>, <i>Lasiodiplodia iraniensis</i> and ten other <i>Lasiodiplodia</i> isolates that may represent two novel species were also identified. <i>Pseudofusicoccum adansoniae</i> (Phyllostictaceae) was only identified from asymptomatic field samples. The inoculation studies confirmed the representative fungal isolates were pathogenic and fulfilled Koch’s postulates, although their virulence varied significantly. The most virulent were isolates of <i>L. rubropurpurea, L. pseudotheobromae, Lasiodiplodia</i> sp. and <i>N. sinoeucalypti.</i> The virulent isolates reproduced symptoms in potted mango plants resembling MTTD in the field, confirming causality. The monitoring of lesion expression over time and analysis of climate data, suggest that drought and heat stress may contribute to the expression of MTTD. <i>Neofusicoccum sinoeucalypti</i> is reported here for the first time in Australia.</p>

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Aetiology of mango twig tip dieback in the Northern Territory of Australia

  • 期刊论文

  • 发表日期：

    2026年1月28日

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  • Naghmeh Nejat,
  • Sharl Mintoff,
  • Priyanka Sharma,
  • Jane D. Ray

摘要

Mango twig tip dieback (MTTD) was first observed in the outer Darwin rural area, Northern Territory, in 2017. The disease is characterised by dark necrotic lesions on the twigs of mango trees that extend rapidly causing death of the apical bud, the twig dieback symptoms are also associated with general tree decline, branch death, and reduced productivity. Since its first detection in Darwin, MTTD is now widespread in commercially grown Kensington Pride mangoes and is of major concern to the mango growers in the region. In this study, fungi were isolated and identified from symptomatic and asymptomatic mango twigs. MTTD symptoms are associated with members of the Botryosphaeriaceae, namely, Lasiodiplodia species, Neofusicoccum sinoeucalypti, and Neoscytalidium dimidiatum. However, Lasiodiplodia species were isolated from 96% of the symptomatic samples. The most frequently isolated species were Lasiodiplodia pseudotheobromae and Lasiodiplodia rubropurpurea, although Lasiodiplodia mahajangana, Lasiodiplodia iraniensis and ten other Lasiodiplodia isolates that may represent two novel species were also identified. Pseudofusicoccum adansoniae (Phyllostictaceae) was only identified from asymptomatic field samples. The inoculation studies confirmed the representative fungal isolates were pathogenic and fulfilled Koch’s postulates, although their virulence varied significantly. The most virulent were isolates of L. rubropurpurea, L. pseudotheobromae, Lasiodiplodia sp. and N. sinoeucalypti. The virulent isolates reproduced symptoms in potted mango plants resembling MTTD in the field, confirming causality. The monitoring of lesion expression over time and analysis of climate data, suggest that drought and heat stress may contribute to the expression of MTTD. Neofusicoccum sinoeucalypti is reported here for the first time in Australia.