Pacific Northwest Vegetable Extension Group

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

Photo Gallery of Vegetable Problems

Spinach

(Click on photo to enlarge)



Diseases


Disease: Anthracnose
Latin binomial: Colletotrichum dematium (= Colletotrichum spinaciae, Colletotrichum dematium f. sp. spinaciae)
Host crops: Spinach.

Photo of symptoms of anthrcnose on spinach Photo of symptoms of anthrcnose on spinach photo of Covair seed with Colletotrichum dematium Photo of a fruiting body of Collectotrichum dematium
Watersoaked lesions on spinach leaves caused by Colletotrichum dematium. Acervuli (fruiting bodies) of Colletotrichum dematium on a spinach seed. An acervulus (fruiting body) of Colletotrichum dematium showing the straight, black setae (‘hairs’) and a gelatinous mass of spores that is readily splash-dispersed.
Photo Source: Jules Riske, Osborne International Seed Co. Photo Source: Lindsey du Toit, Washington State University
Photo of spores of the Anthracnose pathogen
Spores of the Anthracnose pathogen, Colletotrichum dematium.
Photo Source: Lindsey du Toit, Washington State University

Online Resources:

Spinach Diseases: Field Identification, Implications, & Management Practices by Lindsey du Toit, Washington State University, presented on 23 May 2006 at the Organic Seed Alliance Spinach Seed Field Day.

Biology and Management of Spinach Anthracnose. Oklahoma State University

Diseases of spinach ( Spinacia oleracea ) in Arizona: Anthracnose. The University of Arizona

HPIPM: Anthracnose Spinach. Bugwood Wiki.

Spinach: Anthracnose. UC IPM Online, University of California
 



Disease: Cladosporium leaf spot
Causal agent: Cladosporium variable

Photo of Leaf spon complex on spinach Photo of cladosporium leaf spot on spinach Photo of cladosporium leaf spot on spinach Photo of cladosporium leaf spot on spinach Photo of cladosporium leaf spot on spinach
  Very early symptoms of Cladosporium leaf spot on the cultivar ‘Ozarka II’ Necrotic lesions of Cladosporium leaf spot on ‘Winter Bloomsdale’ Severe symptoms of Cladosporium leaf spot in a spinach seed crop. Severe symptoms of Cladosporium leaf spot. Note the sporulation of the fungus in the lesions.
Photo Source:
D.A. Inglis
Photo Source: Lindsey du Toit
Photo of stemphylium leaf spot Photo of stemphylium leaf spot
Symptoms of Cladosporium leaf spot (left, caused by Cladosporium variabile) vs. Stemphylium leaf spot (right, caused by Stemphylium botryosum). Symptoms of Stemphylium and Cladosporium leaf spots on a spinach plant co-inoculated with Stemphylium botryosum and Cladosporium variabile.
Photo Source: Mike Derie

Online Resources:

Pacific Northwest Plant Disease Management Handbook: Spinach (Spinacia oleracea) – Leaf Spot

Crop Profile for Spinach Seed in Washington



Disease: Damping-off/Seedling blight
Pathogen: Aphanomyces, Fusarium, Pythium, and Rhizoctonia species.
Host crops: Most vegetables are susceptible to damping-off/seedling blight including watermelon.

Post-emergence damping-off of spinach seedlings. Note the wilted and dead seedlings in the center of the photos. Damped-off spinach seedlings washed in water to show root symptoms. Note the brown and blackened roots of damped-off seedlings compared to the white root of a healthy seedling.
Post-emergence damping-off of spinach seedlings. Note the wilted and dead seedlings in the center of the photo. Damped-off spinach seedlings washed in water to show root symptoms. Note the brown and blackened roots of damped-off seedlings compared to the white root of a healthy seedling.
Photo Source: Lindsey du Toit, Washington State University

On-Line Resources:

Pacific Northwest Plant Disease Management Handbook: Damping-off in Vegetable Seedlings

Common Diseases: Damping-off. Washington State University Hortsense.

University of California IPM online page on spinach damping-off and root rot.



Disease: Downy Mildew
Pathogen: Peronospora farinosa f. sp. spinaciae

Photo of chlorotic leasions on upper surface of baby leaf spinach crop infected with downy mildew Photo of Gray-brown sporulation of Peronospora farinosa f. sp. spinaciae on a spinach cotyledon Photo of sporulation on the lower spinach leaf surface. Photo of sporangiophore and sporangia of Peronospora farinosa f. sp. spinaciae.
Chlorotic lesions on the upper surface of a baby leaf spinach crop infected with downy mildew. Gray-brown sporulation of Peronospora farinosa f. sp. spinaciae on a spinach cotyledon. Sporulation on the lower leaf surface. Sporangiophore and sporangia of Peronospora farinosa f. sp. spinaciae.
Photo Source: Lindsey du Toit

Online Resources:

Pacific Northwest Plant Disease Management Handbook: Spinach (Spinacia oleracea) – Downy Mildew

UC Pest Management Guidelines: Spinach: Downy Mildew. UC IPM Online. University of California
 

Disease: Fusarium wilt
Pathogen: Fusarium oxysporum f. sp. spinaciae
Host crops: Spinach. Other crops can be asymptomatic hosts, e.g., beet and Swiss chard.

Photo showing variation in severity of Fusarium wilt of spinach Photo showing typical blackening of spinach roots Photo showing spinach plants dying as a result of Fusarium wilt spinach-verticillium-wilt-2
Variation in severity of Fusarium wilt of spinach plants growing in soil sampled from different growers’ fields in western Washington. Typical blackening of spinach roots caused by Fusarium oxysporum f. sp. spinaciae. Spinach plants dying as a result of Fusarium wilt in a spinach seed crop in New Zealand. Longitudinal section through the root system of a healthy spinach plant (left), a spinach plant infected with Verticillium wilt (center), and a spinach plant infected with Fusarium wilt (right). Note the very light vascular discoloration caused by Verticillium wilt vs. dark, black discoloration from Fusarium wilt.
Photo Source: Lindsey du Toit, Washington State University


Online Resources:

Effect of agricultural limestone amendment on Fusarium wilt and Verticillium wilt in a spinach seed crop, 2008. Plant Disease Management Reports

Evaluation of limestone amendments for control of Fusarium wilt in a spinach seed crop, 2006. Plant Disease Management Reports

Fusarium & Verticillium Wilts in Spinach: Research Update
 



Disease: Stemphylium leaf spot
Causal agent: Stemphylium botryosum (asexual stage) (= Pleospora herbarum, sexual stage)

Photo of stemphylium leaf spot Photo of stemphlyium leaf spot Photo of stemphylium leaf spot Photo of stemphylium leaf spot Photo of stemphylium leaf spot
Early symptoms of Stemphylium leaf spot on the cultivar 'Winter Bloomsdale'. Necrotic, expanding lesions of Stemphylium leaf spot. Severe symptoms of Stemphylium leaf spot can resemble herbicide injury. Symptoms of Cladosporium leaf spot (left, caused by Cladosporium variabile) vs. Stemphylium leaf spot (right, caused by Stemphylium botryosum). Symptoms of Stemphylium and Cladosporium leaf spots on a spinach plant co-inoculated with Stemphylium botryosum and Cladosporium variabile.
Photo Source: Lindsey du Toit Photo Source: Mike Derie

Online Resources:

Pacific Northwest Plant Disease Management Handbook: Spinach (Spinacia oleracea) – Stemphylium Leaf Spot

Crop Profile for Spinach Seed in Washington
 



Disease: Verticillium wilt
Causal agent: Verticillium dahliae
Host crops: Numerous vegetables including many brassica vegetables (but not broccoli), cucumber, eggplant, pepper, potato, pumpkin, radish, spinach, tomato, watermelon, etc.

Photo of verticillium wilt of spinach Photo of verticillium wilt of spinach Photo of verticillium wilt of spinach Photo of verticillium wilt of spinach
Symptoms of Verticillium wilt only develop after initiation of 'bolting' (reproductive growth), and start as interveinal chlorosis of the lower leaves that progresses to interveinal necrosis. Longitudinal section through the root system of a healthy spinach plant (left), a spinach plant infected with Verticillium wilt (center), and a spinach plant infected with Fusarium wilt (right). Note the very light vascular discoloration caused by Verticillium wilt vs. dark, black discoloration from Fusarium wilt. Longitudinal section through the stem of a healthy spinach plant (left) and a spinach plant infected with Verticillium wilt (right). The plants were incubated in a moist chamber for a week after they were cut. Note the small black microsclerotia of Verticillium dahliae in the vascular tissue of the infected plant. Closeup of a spinach seed showing microsclerotia (small black spots) and mycelium of Verticillium dahliae.
Photo Source: Lindsey du Toit
Photo of verticillium wilt of spinach
Spinach seeds infected with Verticillium dahliae (six seeds with white mycelium) in a freeze-blotter seed assay.
Photo Source: Lindsey du Toit

Online Resources:

Verticillium Wilt in Spinach Seed Production

Pacific Northwest Plant Disease Management Handbook: Spinach (Spinacia oleracea) – Verticillium Wilt

Crop Profile for Spinach Seed in Washington

See Diseases, pests, and other problems common to many vegetables: Verticillium wilt

Fusarium & Verticillium Wilts in Spinach: Research Update
 

Insect/Mite Pests


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 lygus bug damage on a spinach seed crop Photo of lygus bug damage on spinach seed crop Photo of a lygus bug on a Swiss chard plant
Lygus bugs cause damage in spinach seed crops by feeding on the developing flowers and seed. A black sticky substance is often produced at the site of feeding injury. A lygus bug on a Swiss chard plant. Note the wing pads developing on the insect.
Photo Source: Lindsey du Toit, Washington State University Photo Source: Bev Gerdeman, WSU Entomologist

Online Resources:

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

Common name: Spider mite
Latin binomial: Tetranychus spp. including twospotted spider mite (Tetranychus urticae), strawberry spider mite (Tetranychus turkestani), and Pacific spider mite (Tetranychus pacificus)
Host crops: Wide host range, including many vegetables such as bean, carrot seed crops, potato, etc.

Photo of spinach leafminer damage on leaf Closeup photo of spinach leafminer damage on leaf Photo of severe spinach leafminer injury Phot of spinach leafminer eggs
Severe spider mite infestation in a spinach seed crop.      
Photo Source: Bev Gerdeman, WSU Entomologist    
Two-spotted spider mite adult and eggs on a potato leaf. Eggs of the two-spotted spider mite, Tetranychus urticae.
Two-spotted spider mite adult and eggs on a potato leaf. Eggs of the two-spotted spider mite, Tetranychus urticae.
Photo Source: Silvia Rondon, Oregon State University

On-Line Resources:

Carrot seed – Twospotted spider mite. PNW Insect Management Handbook, Chapter: Vegetable Seed, Section: Carrot Seed.

See Diseases, pests, and other problems common to many vegetables: Spider mites.

Managing spider mites in gardens and landscapes. University of California Online Statewide Integrated Pest Management Program.


Common name: Spinach leafminer
Latin binomial: Pegomya hyoscyami
Host crops: Spinach, beet, sugar beet, Swiss chard, and many weeds including lamb’s-quarters, chickweed, and nightshade

Photo of spinach leafminer damage on leaf Closeup photo of spinach leafminer damage on leaf Photo of severe spinach leafminer injury Phot of spinach leafminer eggs
Typical symptoms of spinach leafminer injury. Early symptoms of leafminer injury caused by larvae tunneling within a spinach leaf beneath the epidermis. Severe spinach leafminer injury with numerous black faeces produced by larvae tunneling/feeding within the leaf. Four white eggs of the spinach leafminer.
Photo Source: Lyndon Porter, USDA-ARS Photo Source: Scott Chichester, vegetable grower Photo Source: Lyndon Porter, USDA-ARS
Photo of leafminer larva feeding within a leaf Photo of scarring caused by the adult spinach leafminer
Epidermis of the spinach leaf pulled back from a leaf mine to reveal two larvae feeding within the leaf. The small black specks within the leaf mine are faeces produced as the larvae feed. Scarring caused by the adult spinach leafminer, a fly.
Photo Source: Lyndon Porter, USDA-ARS Photo Source: Lindsey du Toit, WSU

Online Resources:

Pacific Northwest Insect Management Handbook: Spinach – Leafminer

Spinach: Leafminers, UC IPM Online, University of California Agriculture & Natural Resources

Leafminers (vegetables), Wisconsin Horticulture, University of Wisconsin Cooperative Extension
 


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 showing severe damage to a hybrid spinach seed crop caused by subterranean springtails in wet, cool spring conditions. Note the extensive areas of poor stands and stunted plants. Photo showing range in severity of stunting Photo showing severe discoloration and damage to spinach seedling roots Photo of feeding injury to spinach roots by subterranean springtails
Severe damage to a hybrid spinach seed crop caused by subterranean springtails in wet, cool spring conditions. Note the extensive areas of poor stands and stunted plants. Range in severity of stunting caused by subterranean springtails in a spinach seed crop. Severe discoloration and damage to the roots of a spinach seedling, caused by subterranean springtails. Feeding injury to spinach roots by subterranean springtails.
Photo Source: Lindsey du Toit, Washington State University
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

Online Resources:

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

Also, see Swiss Chard: Springtails



Common name (of damaging stage): Wireworm (adults are called click beetles or snapping beetles)
Latin binomial: Ctenicera spp. and Limonius spp. Several kinds of wireworms are in the Pacific Northwest. Wireworms causing the most damage in irrigated areas are the Pacific Coast wireworm (Limonius canus), the sugar beet wireworm (L. californicus), the western field wireworm (L. infuscatus), and the Columbia Basin wireworm (L. subauratus). The Pacific Coast and sugar beet wireworms are the most common. Where annual rainfall is <15 inches, the Great Basin wireworm (Ctenicera pruinina) may be a problem, especially when irrigated crops are grown on sagebrush or dry wheat land. This species usually disappears after a few years of irrigation, but may be replaced by Limonius spp. which are favored by moist conditions. West of the Cascades, other wireworm species are pests, including Agriotes spp.
Host crops: All crops are susceptible to wireworm, but this pest is most destructive on beans, carrot, corn, grain, onion, potatoes, spinach seed crops, and other annual crops in the PNW.

Photo of wireworm adult Photo of wireworm larva Photo of monitoring wireworm density closeup of wireworm
Adult wireworm is commonly known as a click beetle. Beetle size 3/8 to 1/2 inch (8–12 mm). Wireworm larva is dark orange or brown and mature larvae are 3/8 to 1/2 inch in length. Wireworm larvae density can be monitored with oatmeal bait.  
Photo Source: David Horton, USDA-ARS, Wapato Photo Source: Lindsey du Toit, Washington State University
A click beetle of the species Agriotes obscurus, the larvae of which are wireworms. A click beetle of the species Limonius californicus, the larvae of which are wireworms. A click beetle of the species Limonius canus, the larvae of which are wireworms.
A click beetle of the species Agriotes obscurus, the larvae of which are wireworms. A click beetle of the species Limonius californicus, the larvae of which are wireworms. A click beetle of the species Limonius canus, the larvae of which are wireworms.
Photo Source: Oregon State University – Oregon State Arthropod Collection.

 

Online Resources:

Pacific NorthwestInsect Management Handbook: Vegetable crop pests – Wireworm

Managing Wireworms in Vegetable Crops. Ontario Ministry of Agriculture and Food

Wireworms VegEdge, University of Minnesota

Wireworms & Click Beetles. Washington State University

Spinach: Wireworms. UC IPM Online, University of California

Wireworm Field Guide - A guide to the identification and control of wireworms, Syngenta Crop Protection Canada, Inc.

Wireworm Biology and Nonchemical Management in Potatoes in the Pacific Northwest, N. Andrews, M. Ambrosino, G. Fisher, and S.I. Rondon, Pacific Northwest Extension Publication no. PNW607

See Diseases, pests, and other problems common to many vegetables: Wireworm
 

Abiotic Problems


Herbicide Injury:

Problem: Clomazone (Command) herbicide residual carryover in spinach

Crops affected: Spinach and many other crops sensitive to clomazone develop symptoms of whitening of the foliage if planted too soon after an application of the herbicide clomazone (Command). It is very important to follow crop rotation intervals recommended on the label to avoid such injury.

Symptoms of white foliage caused by planting spinach into soil with residual clomazone herbicide from a crop grown preceding spinach. Symptoms of white foliage caused by planting spinach into soil with residual clomazone herbicide from a crop grown preceding spinach.
Symptoms of white foliage caused by planting spinach into soil with residual clomazone herbicide from a crop grown preceding spinach.
Photo Source: Tim Miller, Washington State University Weed Scientist

Online Resources:

Spinach: Integrated Weed Management. University of California IPM Pest Management Guidelines.

Command® 3ME. Maufacturer's product information page, FMC Corporation.


Common name: Edema
Cause: A physiological problem prominent when air is cooler than the soil, soil moisture is high, and relative humidity is high. The low plant transpiration rates combined with an increase in water absorption by roots from the soil leads to increased cell turgor pressure, resulting in eruption of epidermal cells as the inner cells enlarge. Protrusion of the inner cells causes epidermal cells to die and discolor, resulting in a ’warty’ appearance that can be misidentified as a disease. Symptoms are usually worse on the lower leaf surface and on older (lower) leaves.
Host Crops: Numerous vegetables including spinach, brassicas, tomato, etc. Vegetables with waxy leaves, e.g., brassicas, tend to be most susceptible.
Photo Source: Pop Vriend Seed Co.

Photo of Edema on Spinach Photo of Edema on Spinach Photo of Edema on Spinach
Symptoms of edema on the lower surface of spinach leaves, showing burst and calloused epidermal cells.

Photo Source: Pop Vriend Seed Co., Holland


Online Resources:
University of Delaware: Edema on Cole Crop Leaves

University of Massachusetts: Edema Spring Crops

What are these bumps on my vegetables? Edema or oedema: It doesn’t matter how you spell it, it still doesn’t look good. What is it, what causes it and how can I prevent it? Michigan State University Extension

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Contact Us: Lindsey du Toit and Carol Miles