Spinach

Diseases

Insect/Mite Pests

Abiotic Problems

Diseases

Anthracnose

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

Online Resources:

• Spinach Diseases: Field Identification, Implications, & Management Practices (pdf) 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 (pdf). 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.

Return to the Top

Cladosporium leaf spot

Disease: Cladosporium leaf spot
Causal agent: Cladosporium variable

Online Resources:

• Pacific Northwest Plant Disease Management Handbook: Spinach (Spinacia oleracea) – Leaf Spot.
• Crop Profile for Spinach Seed in Washington (pdf).

Return to the Top

Damping-off/Seedling blight

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.

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.

Return to the Top

Downy Mildew

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

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.

Return to the Top

Fusarium wilt

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

Online Resources:

• Effect of agricultural limestone amendment on Fusarium wilt and Verticillium wilt in a spinach seed crop, 2008 (pdf). Plant Disease Management Reports
• Evaluation of limestone amendments for control of Fusarium wilt in a spinach seed crop, 2006 (pdf). Plant Disease Management Reports
• Fusarium & Verticillium Wilts in Spinach: Research Update (pdf).

Return to the Top

Stemphylium leaf spot

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

Online Resources:

• Pacific Northwest Plant Disease Management Handbook: Spinach (Spinacia oleracea) – Stemphylium Leaf Spot.
• Crop Profile for Spinach Seed in Washington (pdf).

Return to the Top

Verticillium wilt

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.

Online Resources:

• Verticillium Wilt in Spinach Seed Production (pdf).
• Pacific Northwest Plant Disease Management Handbook: Spinach (Spinacia oleracea) – Verticillium Wilt.
• Crop Profile for Spinach Seed in Washington (pdf).
• See Diseases, pests, and other problems common to many vegetables: Verticillium wilt.
• Fusarium & Verticillium Wilts in Spinach: Research Update (pdf).

Return to the Top

Insect/Mite Pests

Lygus bugs

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.

Online Resources:

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

Return to the Top

Spinach leafminer

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.

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.

Return to the Top

Spider mites

Common name: Spider mites
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.

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.

Return to the Top

Springtails 

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.

Online Resources:

• Springtails in Sugarbeet: Identification, Biology, and Management (pdf). North Dakota State University, Fargo.
• Control of Subterranean Springtails in Sugarbeet Using Granular, Liquid, and Seed Treatment Insecticides (pdf). North Dakota State University, Fargo.
• Springtail feeding on emerging crops (especially sugarbeet) (pdf). Michigan State University.
• Pest: Springtail. Pest Spotter, Bayer CropScience.
• Also, see Swiss Chard: Springtails.

Return to the Top

Wireworm

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.

Online Resources:

• Pacific NorthwestInsect Management Handbook: Vegetable crop pests – Wireworm.
• Wireworms VegEdge, University of Minnesota.
• Spinach: Wireworms. UC IPM Online, University of California.
• Wireworm Field Guide (pdf) – A guide to the identification and control of wireworms, Syngenta Crop Protection Canada, Inc.
• Managing Wireworms in Vegetable Crops. Ontario Ministry of Agriculture and Food.
• 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.

Return to the Top

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.

Online Resources:

• Spinach: Integrated Weed Management. University of California IPM Pest Management Guidelines.
• Command® 3ME. Maufacturer’s product information page, FMC Corporation.

Return to the Top

Edema

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.

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.

Return to the Top

Our pages provide links to external sites for the convenience of users. WSU Extension does not manage these external sites, nor does Extension review, control, or take responsibility for the content of these sites. These external sites do not implicitly or explicitly represent official positions and policies of WSU Extension.