Pacific Northwest Vegetable Extension Group

of Washington State University, Oregon State University, and University of Idaho

Photo Gallery of Vegetable Problems

Radish

(Click on photo to enlarge)

General Disease Management in Radish

Crucifer Disease Guide - A Practical Guide for Seedsmen, Growers and Agricultural Advisors. Published by Seminis Vegetable Seeds, Inc.’s Plant Health Department and Seed Health Departments.

Small-Scale Cost-Effective Hot Water Seed Treatment
Reduce the risk of seed-borne diseases, especially for organic Brassica growers.

Diseases

Disease: Black Leg
Pathogens: Phoma lingam (sexual stage = Leptosphaeria maculans)
Host crops:Most members of the Brassicaceae (Cruciferae) = cabbage family, including broccoli, Brussels sprouts, cabbage, canola, cauliflower, various Chinese brassica vegetables, collard, kale, mizuna, mustard, oilseed rape, oilseed turnip rape, rutabaga, turnip, etc.), Sinapis (white and yellow mustard), and Raphanus (daikon and radish). Several wild species exist that may be infected by P. lingam including Descurainia (tansymustard), Sisymbrium (hedge mustard), and Thlaspi (penny-cress). This is a quarantine disease in six counties in northwestern WA and all counties east of the Cascade Mountains because of the risk of this pathogen to the brassica vegetable seed industry.

hypocotyl infection with pycnidia growout trial – cotyledon symptoms Black leg oozing pycnidia
Black leg symptoms on a cabbage seedling grown from an infested seed lot. Note the small, black fruiting bodies (pycnidia) on the hypocotyl of the seedling. Black leg infection of the cotyledon of a cabbage seedling grown from an infested seed lot. Note the small, black fruiting bodies (pycnidia) on the cotyledon. Pycnidia of Phoma lingam on the base of the stem of a Brassica rapa plant, showing pink cirrhi oozing out of each pycnidium, containing thousands of conidia. The conidia are readily splash-dispersed.
Photo Source: Lindsey du Toit, Washington State University.
Black leg lesion at the base of the stem of an infected plant Phoma leaf spot – Cindy Ocamb Phoma lingam seed assay – cauliflower 19x
Black leg lesion at the base of the stem of an infected plant from a Brassica rapa seed crop. Note the small, black pycnidia embedded in the lesion. Phoma leaf spot lesion with tiny, black pycnidia present in the necrotic, circular lesion, surrounded by a narrow, chlorotic (yellow) halo. Black pycnidia of the black leg fungus, Phoma lingam, on an infected cauliflower seed. Note the amethyst-colored cirrhi (gelatinous matrix) oozing from the pycnidia, which indicates the strain of the pathogen is virulent (able to cause Phoma leaf spot or black leg of brassicas)
Photo Source: Cynthia Ocamb, Oregon State University. Photo Source: Lindsey du Toit, Washington State University.

 

On-Line Resources:

Video: Blackleg Disease and Resistance Management. Published by the Canola Council of Canada.

Pacific Northwest Plant Disease Management Handbook: Cabbage and Cauliflower (Brassica sp.)-Black Leg and Phoma Root Rot

Pacific Northwest Plant Disease Management Handbook: Seed Crop, Crucifers-Blackleg

Black leg in Brassicaceae crops and wild crucifers: 2014 outbreak in the Willamette Valley of Oregon

Black Leg, Light Leaf Spot, and White Leaf Spot, Cynthia Ocamb, PhD., Plant Pathologist, OSU Extension, Associate Professor--Botany & Plant Pathology.

Fungicides for Control of Black Leg, David Priebe, Pesticides Program, Oregon Department of Agriculture.

Addressing Blackleg in the Willamette Valley: Oregon Department of Agriculture permanent ruling released on black leg of brassicaceae in January 2015 – see the Brassica Production Districts document, and the OSDA Permanent Ruling document titled ‘Crucifer blackleg disease requirements moved into one regulation; removes same requirements from rapeseed production districts,’ below.

Management of Black Leg in Oregon on Brassica seed crops, a Clinic Close-up, Oregon State University Extension Service.

Management of Black Leg in Oregon on Vegetable Brassica Crops and Seed Crops, a Clinic Close-up, Oregon State University Extension Service.

Disease: Black rot
Pathogens: Xanthomonas campestris pv. campestris
Host crops: Most members of the Brassicaceae (Cruciferae) = cabbage family, including broccoli, Brussels sprouts, cabbage, canola, cauliflower, various Chinese brassica vegetables, collard, kale, mizuna, mustard, oilseed rape, oilseed turnip rape, rutabaga, turnip, etc.), Sinapis (white and yellow mustard), and Raphanus (daikon and radish). Most wild species can be infected by this pathogen. This is a quarantine disease in parts of six counties in northwestern Washington because of the risk of this pathogen to the brassica vegetable seed industry. 

Title Cabbage stem showing blackening 
of the vascular tissue caused by the black rot pathogen, <em>Xanthomonas 
campestris </em>pv. <em>campestris</em>. Dieback and wilting of cabbage plants following a severe outbreak of black rot. Blackening of the veins of a cabbage 
leaf following inoculation with the black rot pathogen, <em>Xanthomonas
campestris </em>pv. <em>campestris</em>.
Cabbage black rot symptoms of marginal chlorosis and v-shaped lesions extending into the leaf. Cabbage stem showing blackening of the vascular tissue caused by the black rot pathogen, Xanthomonas campestris pv. campestris. Dieback and wilting of cabbage plants following a severe outbreak of black rot. Blackening of the veins of a cabbage leaf following inoculation with the black rot pathogen, Xanthomonas campestris pv. campestris.
Photo Source: Mike Derie, Washington State University Photo Source: Lindsey du Toit, Washington State University
Severe blackening of the veins of a cabbage leaf 
infected with <em>Xanthomonas campestris </em>pv. <em>campestris</em>. Wilting of a cabbage leaf infected with <em>Xanthomonas campestris </em>pv. <em>campestris</em>. Symptoms of leaf spot caused by <em>
campestris </em>pv. <em>armoraciae</em> (left) and <em>X. campestris </em>pv. <em>raphani </em>(right), two bacterial pathogens closely related to the black rot pathogen, <em>X. campestris </em>pv. <em>campestris</em>.
Severe blackening of the veins of a cabbage leaf infected with Xanthomonas campestris pv. campestris. Wilting of a cabbage leaf infected with Xanthomonas campestris pv. campestris. Symptoms of leaf spot caused by  Xanthomonas campestris pv. armoraciae (left) and X. campestris pv. raphani (right), two bacterial pathogens closely related to the black rot pathogen, X. campestris pv. campestris.
Photo Source: Lindsey du Toit, Washington State University

Online Resources:

Cabbage and Cauliflower (Brassica sp.)-Black Rot, Pacific Northwest Handbooks, a Pacific Northwest Extension Publication.

Black Rot of Crucifers, Fact Sheet, Cooperative Extension, New York State, Cornell University.

Field Scouting Guide: Black Rot of Brassicas, Growing Produce, Meister Media Worldwide’s Horticulture Group.

Managing Black Rot of Cabbage and other Crucifer Crops in Organic Farming Systems, eOrganic, eXtension Foundation (extension.org).

Brassicas, Black Rot, UMass Extension vegetable Program Fact Sheet, Center for Agriculture, Food and the Environment, College of Natural Sciences, University of Massachusetts, Amherst, MA.


Disease: Clubroot of brassica vegetables
Pathogen: Plasmodiophora brassicae
Host crops: Broccoli, cabbage, cauliflower, brassicaceae (cruciferous) weeds, and radish.

Photo of below-ground symptoms of clubroot.
Below-ground symptoms of clubroot.
Photo Source: Lindsey du Toit

On-Line Resources:

Pacific Northwest Plant Disease Management Handbook: Cabbage and Cauliflower (Brassica) – Clubroot

Clubroot of Crucifers. Vegetable MD Online.

Clubroot. Wikipedia.

Clubroot of vegetable brassicas – towards integrated control. New Zealand Institute for Crop & Food Research Ltd.

Clubroot of Crucifers. The Ohio State University Extension.

Managing Clubroot: Equipment Sanitation Guide. Canola Council of Canada

Top 10 tips from the 2013 International Clubroot Workshop. Canola Watch, Canola Council of Canada.

See Diseases, pests, and other problems common to many vegetables: Clubroot of brassica vegetables.
 

Disease: White rust
Pathogen: Albugo candida

Photo of white rust on radish
Photo Source: G.Q. Pelter

On-Line Resources:

Pacific Northwest Plant Disease Management Handbook: Radish (Raphanus sativus) – White Rust

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WSU Mount Vernon NWREC, 16650 State Route 536, Mount Vernon, WA 98273-4768, 360-848-6120
Contact Us: Lindsey du Toit and Carol Miles