Help identifying and dealing with an orchid pest

(Question)

Hi! I recently found these tracks on my orchid leaf. Could you help me identify the pest and how to deal with it, please? (I’ve attached a photo.)

Thank you!

(Answer)

Thank you for contacting the Toronto Master Gardeners’ with your question about marks on your orchid leaf.  While these track markings are unusual, it is difficult to pinpoint a specific pest from this sign alone.  Scale is a common orchid pest that appears as grey / brown oval bugs, sometimes in lines.  It differs from your picture however, as typically scale infested areas appear powdery and individual bugs are visible.  Viral infections can cause unusual leaf markings. These would typically be visible on the top and underside of the leaves.

In order to better identify the markings on your leaf, look at the other plant leaves to see if there are similar markings.  Check the under side of the leaves for markings or signs of insects.  Look at the crevices where leaves join the stem.  A moistened cotton swab can be used to gently sweep the crevice and then examined for pests.  Finally, check the surface of the growing medium for evidence of pests.  Please feel free to contact us again if you identify additional information and we will do our best to help with a more precise identification.

It is also possible that your orchid leaf was has had a minor trauma – scratched or rubbed against a plant pot or other firm object.

The American Orchid Society has a detailed post regarding multiple orchid pests included in the link below.  A link to the Toronto Master Gardeners’ Gardening Guide regarding Orchid Care is also attached as good cultural practices will help to prevent insect pests.

https://www.torontomastergardeners.ca/gardeningguides/growing-orchids-a-toronto-master-gardeners-guide/

https://www.aos.org/orchids/orchid-pests-diseases.aspx