Potyvirus in Korean radish

This sample came in before the winter break from a grower who specializes in Asian vegetables. A bag full of Korean radishes (also known as tae baek)- white & green very large (~6 inches long and ~3 inches diameter) radishes. This sample presented with leaf curling and dark flecks in the root tissue. Never having encountered a Korean radish before, I had to research the seed catalogs online to see if the green shoulders were normal (they are). The sample was in the cooler for too long and the foliage was beginning to deteriorate, so no picture but symptoms were similar to those caused by viruses.

Possibilities: virus or abiotic (herbicide, nutrient deficiency).

Tests done: CMV (ImmunoStrip assay from Agdia), POTY (elisa assay from Agdia)

Results: (-)CMV, (+)Potyvirus

In case you missed it: Greenhouse Virus Presentation

This presentation was part of the Dec '09 Front Range Greenhouse IPM workshop: Viruses Affecting Production. I'm hoping to get a narrated version up but it won't be for a few weeks.
Enjoy and as always contact me if you need more information!

Common Greenhouse Viruses

View more presentations from bedmunds.

Upcoming Greenhouse Workshop

Front Range Greenhouse IPM Workshop:
Viruses Affecting Production

Two locations:

Dec. 3rd 9-12pm: Gulley Greenhouse & Garden Center
6029 S. Shields, Fort Collins
OR
Dec. 8th, 9-12pm: Center Greenhouse, 1550 E. 73rd Ave, Denver

Who should attend: Greenhouse growers and pest management staff

Topics to be covered :

Identifying and managing common viruses affecting production stock in greenhouses

Presented by Brooke Edmunds, Ph.D.; Regional Specialist, Colorado State University Extension

How to identify and manage the most common viruses that affect production stock including TMV, INSV, TSWV, and CMV. There will be plenty of time to answer questions!

Virus testing: The why, when, and how of virus testing

Why is clean stock important to your operation? How do I submit plant samples for virus testing to the Plant Diagnostic Lab in Adams County? There will also be a hands-on opportunity to practice using Agdia ImmunoStrip® to test in-house.

The Colorado Department of Agriculture Phytosanitary Program: What you need to know

Presented by Laura Pottorff, M.S.; Nursery, Seed and Phytosanitary Program Manager, Colorado Department of Agriculture

Laura will outline the CDA phytosanitary certificate and inspection process.

Cost : $20/person to cover supplies and a light breakfast ($25 if not a member of CNGA)

***You must preregister!***

To register: e-mail brooke.edmunds@colostate.edu or call 303/637-8016

Cucumber Mosaic Virus (CMV) on Houstonia

It has been interested to see the wide range of symptoms that can be caused by virus. We received plugs of Houstonia caerulea into the diagnostic lab last week with leaf spots and dieback on the flower stalks. The spots themselves had a orange brown color. The root systems looked great-white, healthy looking, not pot-bound.
We incubated a few plugs in a moist chamber and plated the leaf spots onto CMA and PDA. No fungal growth and no sporulation ever occurred. There was also never any bacterial growth or streaming noted. Running out of possibilities , I decided to test with an AgDia combo strip for CMV, INSV, TSWV and TMV. The Houstonia tested postive for Cucumber Mosaic Virus (CMV)! I reran the test to confirm and again it was positive. I haven't been able to find a record of Houstonia being a host for CMV, yet (I'll admit I haven't done a concise search). The symptoms are interesting-with bright orange speckles on the leaf tissue and stems. (Click on any photo for a larger version.)

Close-up of foliage-note orange speckling.

This is the base of the stem, which also showed the orange speckling.

CMV is spread by aphids but also by mechanical transmission-meaning that workers can spread the virus when taking cuttings or otherwise moving infected plant sap.

Vinca minor-CMV (Cucumber Mosaic Virus)

This sample is Vinca minor from a propagation operation. The sample tested positive for CMV (Cucumber Mosaic Virus) using an Agdia immunostrip test.
CMV has a very wide host range and affects both vegetables and ornamental plants. Aphids are the primary source of infection but infection by mechanical transmission (taking cuttings, etc) is also possible. Infected plants should be destroyed to avoid spreading the virus within a greenhouse.

Aster-TSWV (Tomato spotted wilt virus)

This sample is Aster x Frikartii 'Monch' from a propagation operation showing signs of virus infection. The sample tested positive for TSWV (Tomato Spotted Wilt Virus) using an Agdia immunostrip test. TSWV & INSV (Impatiens Necrotic Spot Virus) are two related and very common viruses in greenhouse production. Cornell University has an excellent fact sheet with more information on these viruses.