Pacific Northwest Vegetable Extension Group

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

Photo Gallery of Vegetable Problems

Swiss Chard

(Click on photo to enlarge)

Diseases

Disease: Ramularia leaf spot
Pathogen: Ramularia beticola
Host crops: Most vegetables in the Chenopodiaceae, i.e., sugar beet, table beet, and Swiss chard.

Photo of leaf spot on Swiss chard Photo of Leaf spot on Swiss chard Photo of necrotic leaf spots caused by Ramularia beticola Phot of discrete, circular, necrotic lesions of Ramularia leaf spot Photo of two-celled hyaline spores of Ramularia beticola
Ramularia leaf spot on Swiss chard leaves. Typical large, necrotic leaf spots caused by Ramularia beticola on a leaf sampled from a Swiss chard seed crop. Discrete, circular, necrotic lesions of Ramularia leaf spot on a leaf sampled from a Swiss chard seed crop. Two-celled, hyaline spores of Ramularia beticola from an infected Swiss chard leaf.
Photo Source: D.A. Inglis,
Washington State University
Photo Source: Lindsey du Toit,
Washington State University

On-Line Resources:

Pacific Northwest Plant Disease Management Handbook: Sugar Beet (Beta vulgaris) – Ramularia Leaf Spot
 

Disease: Rhizoctonia basal petiole and crown infection
Pathogens:Rhizoctonia
Host crops: Many vegetables are susceptible to infection by Rhizoctonia spp., which are common soilborne fungi. In beet and Swiss chard, these fungi can infect the base of petioles and the crown or main root at or below the soil surface, particularly in moist soil conditions. During very wet conditions, infection can also occur on the leaves.

Rhizoctonia on Chard seed crop. Swiss chard Rhizoc lesion. Rhizoctonia on Chard foliar lesions. Rhizoctonia on Chard closeup.
Severe root and crown symptoms caused by infection of plants in a Swiss chard seed crop by Rhizoctonia. Lesion at the base of a Swiss chard petiole caused by Rhizoctonia. Swiss chard foliar lesions caused by Rhizoctonia. Severe root, crown, and petiole infection by Rhizoctonia on a Swiss chard plant.
Photo Source: Lindsey du Toit, Washington State University

Online Resources:

Pacific Northwest Plant Disease Management Handbook

Insect/Mite Pests

Common name: Aphids (various types)
Latin binomial: Aphis fabae (bean aphid), Myzus persicae (green peach aphid)
Host crops: Table beet, sugar beet, Swiss chard, and various other vegetable and weed plant species

Aphids in a Swiss chard seed crop. Note the blackened stems and leaves as a result of sooty mold fungi growing on the honeydew exudate (sugary, sticky exudate) produced by the aphids. Close-up image of aphids on a Swiss chard plant in a seed crop. Note the blackened stems and leaves as a result of sooty mold fungi growing on the honeydew exudate (sugary, sticky exudate) produced by the aphids, as well as the shriveled white cast ‘skins’ produced by aphids as they moult.
Aphids in a Swiss chard seed crop. Note the blackened stems and leaves as a result of sooty mold fungi growing on the honeydew exudate (sugary, sticky exudate) produced by the aphids. Close-up image of aphids on a Swiss chard plant in a seed crop. Note the blackened stems and leaves as a result of sooty mold fungi growing on the honeydew exudate (sugary, sticky exudate) produced by the aphids, as well as the shriveled white cast ‘skins’ produced by aphids as they moult.
Photo Source: Lindsey du Toit, Washington State University

Online Resources:

http://insect.pnwhandbooks.org/vegetable/vegetable-pests/hosts-and-pests/chard-swiss-aphid


Common name
: Lygus bugs
Latin binomial: Lygus spp.
Host crops: Numerous different species of vegetables and other crops, e.g., alfalfa, beet, cabbage, carrot, spinach, Swiss chard, etc. Lygus bugs can cause different types of damage to various growth stages of different crops. They cause blackheart on celery, blasting on flower tissues, collapse of asparagus spears, decreased yields in carrot, beet, spinach, and other seed crops, etc.

Photo of damage to swiss chard from lygus bug feeding Photo of damage to a swiss chard leaf as result of injury by lygus bugs Photo of an early nymphal instar of a lygus bug on a Swiss chard plant in a seed crop Photo of a lygus bug nymph feeding on the flowers of a Swiss chard plant in a seed crop
Black streaks on the main stem, and black discoloration and dieback of the buds at the tip of a flowering plant from a Swiss chard seed crop in western Washington, resulting from feeding injury caused by lygus bugs. Dark lesions on the midrib, and necrosis/dieback of the tip of a leaf from a Swiss chard seed crop as a result of injury caused by lygus bugs. An early nymphal instar of a lygus bug on a Swiss chard plant in a seed crop. A lygus bug nymph feeding on the flowers of a Swiss chard plant in a seed crop in western Washington.
Photo Source: Bev Gerdeman, WSU Entomologist
Photo of a lygus bug on a Swiss chard plant
A lygus bug on a Swiss chard plant. Note the wing pads developing on the insect.
Photo Source: Bev Gerdeman, WSU Entomologist

On-Line Resources:

Pacific Northwest Insect Management Handbook: Vegetable crop pests – Lygus bug
 

Common name: Springtails (subterranean types)
Latin binomial: Order Collembola. There are numerous types of springtails or collembola, which are divided into two groups – subterranean springtails and surface springtails.
Host crops: Multiple vegetables, but most damage has been reported on spinach and beets, primarily in heavier, organic soils during very wet, cool spring conditions.

Photo of a subterranean springtail extracted from soil in a spinach seed crop Photo of a subterranean springtail extracted from soil in a spinach seed crop
A subterranean springtail extracted from soil in a spinach seed crop.
Photo Source: Lindsey du Toit, Washington State University

On-Line Resources:

Springtails Springtails in Sugarbeet: Identification, Biology, and Management. North Dakota State University, Fargo

Control of Subterranean Springtails in Sugarbeet Using Granular, Liquid, and Seed Treatment Insecticides. North Dakota State University, Fargo

Springtail feeding on emerging crops (especially sugarbeet). Michigan State University

Pest: Springtail. Pest Spotter, Bayer CropScience

Abiotic Problems

Herbicide Injury

Problem: Injury from application of specific herbicides to certain parent lines in seed crops, higher rates of application of some herbicides, or application of tank mixes (combinations) of some herbicides.

Crops affected: Some table beet and Swiss chard parent lines are more sensitive than others to injury by specific herbicides, even when these products are applied at recommended (labeled) rates; or injury can occur when higher rates of certain herbicides are applied to beet and chard crops; or injury may occur when certain herbicides are applied in tank-mix combinations.

Symptomatic plants from a Swiss chard seed crop resulting from injury after application of a combination of herbicides. Photo source: Swiss chard seed grower. Symptomatic plants from a Swiss chard seed crop resulting from injury after application of a combination of herbicides. Photo source: Swiss chard seed grower. Symptomatic plants from a Swiss chard seed crop resulting from injury after application of a combination of herbicides. Photo source: Swiss chard seed grower.
Symptomatic plants from a Swiss chard seed crop resulting from injury after application of a combination of herbicides.
Photo Source: Swiss chard seed grower

Online Resources:

Herbicide Symptoms, University of California, Division of Agriculture and Natural Resources

Herbicide Modes and Action and Symptoms on Plants, Richard Smith, Farm Advisor, University of California Cooperative Extension.

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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