What is on these leaves?

POSTED IN For Growers, For Members ON 5/28/2013

Brad Reddekopp, of Hazelton BC, sent the picture shown below, reporting:

Subject: White fuzzy growths on Saskatoon leaves

This has to do with wild Saskatoon berry bushes in north-west British Columbia. This year, I’ve noticed some strange, fuzzy white growths on the leaves and I’m wondering what they are.

Discussion ensued on Facebook before his submission to the Institute, suggesting spider mites or larval cocoons.

Our resident specialist, Erwin “Duke” Elsner, Small Fruit Educator with Michigan State University Extension, responded with:

Hi Brad,

I can’t tell for sure what you are seeing on the Saskatoon leaves, especially since I am only familiar with what infests them in Michigan, but…

Based on many years of investigating leaf deformities on many types of plants, I suspect the causal organism to be a small gall midge or gall wasp.  My hunch is a gall midge, because the growths look to have a natural opening which will later allow the insects to escape from the gall (gall wasps can chew their way out of galls, so they usually do not have a pre-made escape route).

These sorts of insects are often just curiosities, often having no significance to the growth of the plant.

–Duke Elsner

If anyone else has a good idea what this is, please let us all know.

Thank you for asking Brad. We do support wild varieties too.

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