Knowledgebase
Pests of currants #866330
Asked April 29, 2024, 3:01 PM EDT
Jefferson County Colorado
Expert Response
Thanks for contacting the Jefferson County Plant Diagnostic Help Desk.
We cannot identify the red potential insects without seeing them. You could bring in some stems with these structures or send photos to the plant diagnostic help desk: <personal data hidden>. Please note in any email that this is a reply regarding an "Ask Extension" question #0132651.
Several insects do infect currants: aphids (though, while various colors not typically red), spider mites (which are red or pink and quite small), and the larvae of sawflies and borers and fruit flies.
It is safe to remove canes where you see these critters but optimal to know what they are so as to prevent or manage them if they occur in the future, so please let us look at what you are seeing.
Pat B
Best regards,
pat b
Plant Diagnostic Call Center, Horticulture
Colorado State University Extension, Jefferson County
303.271.6627 - Direct
15200 West 6th Ave, Unit C
Golden, CO 80401
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Sent: Wednesday, May 1, 2024 7:01 PM
To: Plant Diagnostics <<personal data hidden>>
Subject: --{EXTERNAL}-- New response added to your question (#0136251)
Hi Jeffco Plant Clinic,
A new response was appended to question #0136251 [ask2.extension.org]
From: | Hugh Gardner |
Subject: | Pests of currants |
Thanks for your interest and reply. There are hundreds of them on a stem. They are not much bigger than pin-head size, but not so small as mites. They might be eggs - they've been there all winter. If you'll give me a mailing address I'll send you samples,
Please join the Ask Extension Experts group in Connect Extension [connect.extension.org]. We will use that group to post updates about Ask Extension.
This message was sent by Ask Extension. If you need help, please visit https://askhelp.extension.org/ [askhelp.extension.org].
I'm following up to make sure your question was answered. The Jeffco Sample Log doesn't have an entry for your currant, so looks like you haven't submitted a sample yet. In place of a physical sample, can you send a photo close-up of the affected branches? You can send here, or directly to the Jeffco Diagnostic Desk: <personal data hidden>.
Best,
Mari H
Mari
We received your sample in the mail - thank you. For reference, we have assigned it as Sample #240028.
Three requests/questions for you:
First, Attached is a copy of a form we require for samples that we receive. Please provide us with the missing information - we have completed as much as we can based on information you have provided so far.
- your billing address, and the address where the currants are growing if they are not the same.
- Please verify that you are a Jefferson County resident.
- Also please see the statement below the address portion of the form, which states: "If we are not able to complete diagnosis/identification, we will send the sample to the CSU Statewide Plan Diagnostic Clinic for evaluation (CSU SPUR). Client will be charged CSU SPUR rates in addition to the Jeffco fee. I give the Jeffco Clinic permission to do this"
- This means: if we are unable to diagnose the problem, we can forward your sample to the state plant lab. We need your permission to do this. It is not required, and the Jeffco Diagnostic Team will evaluate and attempt to diagnose the problem regardless.
- Please respond and let us know if you want the sample to go on to SPUR or to stop with Jeffco.
- A wide shot of the row of bushes, so we can see the area where they are growing.
- A closeup of an individual bush, but trying to get one entire affected bush in the photo.
- Zoomed in photos of the red bumps.
- The sample we received was very dry, and the red bumps were crunchy when we removed one to look at it under the microscope. Are the bumps soft on the plant, or were they dried out when you cut the sample?
- How old are the plants? Have they produced many berries in past years before this problem?
- You mention that the bumps persisted all winter. What month last year did you first notice them? At any point did you notice insects in the vicinity? At any point were the bumps soft on the cane, or sticky? (There appears to be sugary crystals on the cane.)
- Have all canes with the bumps died? What percentage of the plant(s) are affected? How long did it take canes to die once you discovered the bumps?
- Are the leaves healthy, with good color?
- How much/how often are the plants irrigated? Roughly how many hours of sun do they get per day?
Thank you.
Jeffco Volunteer Diagnostician Annette
I'm following up on 'open' questions. I see that your sample to Jeffco Extension was diagnosed as likely White Pine Rust. If you need confirmation, you'll need to submit a sample to the CSU Spur Plant Diagnostic Lab https://agsci.colostate.edu/agbio/plantclinic/
The main management strategy is to prune off and discard (not compost) affected plant parts. See https://extension.umn.edu/plant-diseases/white-pine-blister-rust
Best regards,
Mari Hackbarth
Best,
Mari
Thanks for using the Jeffco Diagnostic service!
Mari Hackbarth