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What are these swollen portions on thimbleberry stalks? #862902

Asked March 30, 2024, 11:22 PM EDT

What are these swollen portions on thimbleberry stalks?

Benton County Oregon

Expert Response

Looks insect related to me but we will need another person to figure that out. Similar to a praying mantis egg case. If you cut into the stem is the gall part of the stem or separate from the stem? There are insects that can infect the stem and cause a gall like this. It might be hollow inside or have chambers. Let us know what you find. 
Jay W. Pscheidt, PhD, Professor Replied April 01, 2024, 8:07 PM EDT

Hello Dr. Pscheidt,

 

Here’s a picture of the inside of the gall on a thimbleberry stalk. This gall appears to be part of the stem.  Your expertise is very much appreciated!

 

Thank you for your help!
Jody Gordon

 

From: ask=<personal data hidden> <ask=<personal data hidden>> On Behalf Of Ask Extension
Sent: Monday, April 1, 2024 5:07 PM
To: jodymarie4 <<personal data hidden>>
Subject: Re: What are these swollen portions on thimbleberry stalks? (#0132825)

 

The Question Asker Replied April 03, 2024, 11:21 PM EDT

Jody:

There are some Cynipid wasps that will create galls in/on the thimbleberry plant. That is what I believe you have. I can see some of the larva in the opened part of the gall. If you want, you can remove the galls but you will not be able to prevent the gall wasp from creating more galls in the future. I am not aware of any treatment that will work except for physical removal of the gall.

Let me know if you have any additional questions. Thank you for contacting us at Extension.

Rich

An Ask Extension Expert Replied April 04, 2024, 1:45 PM EDT

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