Plum skin deformation - Western Flower Thrips

Hi there guys.

I was wondering if anyone could identify what exactly is causing this issue on several older (aprox 25 year) European Italian prune type plum trees. Both these trees grew naturally from seeds off an unknown Italian type plum tree that was much older.

These trees are not setting a lot of fruit and the plum surface is often blemished and many of the plums tend to shrivel and drop. I’m in a mild maritime climate in the Gulf Islands near the San Juan Islands.

Does anyone know exactly what is causing this from pictures of plums from both trees:

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I’ve seen pictures online that seem to resemble the blemishes on the surfaces on some of my plum trees. The pictures I found that resembled this were a result of thrips infestations.

For those familiar with thrips, do these pictures look like thrips are responsible for the blemishing on the plums surface?

Yes, looks like Western Flower thrip damage. A coating of Surround may confuse them. I’ve bagged my nectarines to foil the thrips - it works but might be a lot of work on plums!
There’s also a pheromone from Pest Wizard that you hang on sticky card in trees. Catches lots of insects but not sure if they are thrips.
Since I tried all 3 approaches at once, not sure which is best. But this year I got no thrip damage on nectarines.

How you you bag nectarines to prevent thrips? Thrips start doing damage when flowers are blooming. I can’t bag until fruit are big enough.

@tbg that looked like thrip damage. I see such damage on my nectarines but am not sure if I have noticed them on plums.

Thank you both for your confirmations of thrips damage. Unfortunately I can’t use surround in Canada as our government considers it a controlled pesticide that only those licenced to use pesticides can purchase. Crazy I know, but that’s Canada for you. We’re regulated beyond belief here, so I’m not sure what approach I can take with these critters.

Yes the damage occurs just as flowers set. I used Surround and pheromone traps hoping I could catch the early damage.
And I put bags on when fruit was nickel sized.

I hesitate to spray even with Spinosad due to it being toxic to bees. I live with the damage. So far, it is bearable.

I thinned of those with severe thrip damage before I bagged.

I found some very helpful information online for dealing with thrips:

Interestingly, I’ve only found the thrips damage on my European plums, not Japanese varieties. I don’t have any peach or nectarine trees actually producing fruit yet.

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