An association between invasive apple clearwing moth, Synanthedon myopaeformis (Lepidoptera: Sesiidae), and necrotic cankers on Malus domestica (Rosaceae) trees in British Columbia

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Language of the publication
English
Date
2025-01-06
Type
Article
Author(s)
  • MacDonald, Jesse L.
Publisher
PKP Publishing Services

Abstract

Sudden apple decline (SAD) is complex disease causing rapid mortality in apple trees across North America, typically associated with a necrotic canker near the graft union. To date, causal factors have been diverse and speculative, and infestation with Synanthedon myopaeformis (apple clearwing moth) was identified by producers in British Columbia as a concern related to the disease. Assessments of declining orchards in 2019 showed an association between incidence of necrotic cankers and infestation of S. myopaeformis. Observations of tree stems 15 cm above the graft union showed that 100% of signs of S. myopaeoformis infestation (pupal casings, exit holes, frass) were in necrotic tissue. There was a positive correlation between necrotic canker size and count of S. myopaeformis signs. It is unlikely that S. myopaeoformis infestation is the underlying cause of SAD, but this observational field investigation suggests a relationship between infestations and presence of necrotic cankers, which may be an additional stressor contributing to apple tree collapse associated with SAD.

Plain language summary

Research from the Summerland Research and Development Centre investigated a potential relationship between an invasive moth - apple clearwing moth - and the occurrence of a fungal canker on apple trees. Initial surveys showed that there was a positive relationship between the two, and further work established that the larger the canker, the more apple clearwing moth were likely to be in a given tree. The research, importantly, established a very strong relationship between the presence of the canker on a tree, and the incidence of moth infestation - the canker appears to be an important environment for larval development in the trees. Future work might include whether there is a symbiotic relationship between the pathogen and the moth, and the combined effect of larval infestation and pathogen infection's joint roles in disrupting water flow within the trees - ultimately leading to tree death.

Subject

  • Invasive species

Keywords

  • Clearwing moths

Rights

Peer review

Yes

Open access level

Gold

Article

Journal title
Journal of the Entomological Society of British Columbia
Journal volume
121

Citation(s)

MacDonald, J. L. (2025, January 6). An association between invasive apple clearwing moth, Synanthedon myopaeformis (Lepidoptera: Sesiidae) and necrotic cankers on Malus domestica trees in British Columbia. Journal of the Entomological Society of British Columbia. https://journal.entsocbc.ca/index.php/journal/article/view/2603

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Collection(s)

Animals and insects

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