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Spinach
Scientific name:
Spinacia oleracea
Order/Family:
Caryophyllales: Chenopodiaceae
Pests and Diseases:
Anthracnose  Aphids  Bacterial soft rot  Cucumber Mosaic Virus  Downy mildew  Fusarium wilt  White rust  Turnip mosaic virus  

Green peach aphid (Myzus persicae)

It is a very detrimental insect to spinach. It can transmit diseases that can wipe out large portions of the crop. Aphids and leafminers cause the most serious damage on the crop (University of Georgia). The aphid is pale yellowish in color and small. It lives mainly on the underside of leaves and therefore hard to control.

What to do:
  • Conserve natural enemies. Parasitic wasps and predatory insects, including lady bird beetles, damsel bugs, lacewings, and hover fly larvae are important in natural control of aphids. For more information on natural enemies click here
Aphids
© Magnus Gammelgaard

Bacterial soft rot (Erwinia carotovora)

It is one of the most important diseases. Its symptoms include water soaked tissue and muddy-green or greasy appearance of leaves. Rapid decay occurs and the tissue becomes wet and mushy. This bacterium is found in the soil and in plant debris. It can enter into the plant through mechanical injury, insect injury, disease lesions and other skin punctures.

What to do:
  • Practice rotation with maize, beans, small grains and grasses.
  • Care at harvesting and handling to avoid bruising.
  • A storage temperature just above freezing (0°C) and a relative humidity below 90% does much to reduce soft rot losses.
  • Storage rooms, dump tanks and boxes should be disinfected each season with copper sulfate.

© A. M. Varela, icipe


Soft rot o…

Cucumber Mosaic Virus (CMV)

It is transmitted by the green peach aphids. Symptoms begin as a mottling of the younger inner leaves, which later change to a yellow colour. The symptoms gradually appear on outer leaves, which also change to yellow. The affected leaves curl and wrinkles. Severely affected leaves die. If a plant is affected at the seedling stage, its growth is stunted. The dwarfing, yellowing, corrugation and leaf death are conspicuous symptoms of the disease different from other diseases attacking spinach.

Intensity of the virus increases under long days and intense light. This virus affects, in addition to spinach, a wider group of vegetables, flowers, weeds and ornamentals than any other virus. At least 34 plant families are included as hosts.

What to do:
  • Use resistant varieties (e.g. "Early Hybrid 7").
  • Control aphid vectors throughout the growing season.
  • Control weeds.

Downy mildew (Peronospora spinaciae / Peronospora farinosa)

This fungus is distributed worldwide. It causes leaf spotting that detracts from the quality and appearance. Leaf spots begin as indefinite yellowish areas on the upper leaf surface. A mat of grey to violet mould develops on the corresponding lower surface. With time under cool, wet conditions, the spots enlarge until the whole turns black and dies. The fungus increases profusely in high humidity. The spores can overseason in mild climatesin living spinach, in seeds and in the soil.

What to do:
  • Use resistant varieties (e.g. "Early Hybrid 7")
  • Use certified disease-free seeds. If using own seeds, treat seeds with 500°C for 25 minutes.
  • Practice at least a 3-year rotation and plant in well-drained soil.
Downy mildew
© A.M. Varela, icipe

Fusarium wilt (Fusarium oxysporum f. sp. spinaciae)

It is a wilt that is caused by a fungus. Plants can be affected anytime after the tree-leaf stage. Foliage loses its green luster, gradually wilts and turns yellow, beginning with the oldest leaves. The fungus is soil-borne and seed-borne. It commonly occurs where temperatures are fairly high. It can live in the soil indefinitely and there rotation is not effective in its control.

What to do:
  • Use resistant varieties where available.
  • Use certified disease-free seeds.
Fusarium wilt
© A.M. Varela & A.A.Seif, icipe

Fusarium w…

Fusarium w…

White rust (Albugo occidentalis)

It is a fungus that causes white blister-like pustules on the underside of leaves. They are filled with white spores and the surrounding tissue turns brown and dies. The fungus favors clear, warm, and dry days with cool nights.

What to do:
  • Use resistant varieties where available.
  • Use certified disease-free seeds.
  • A 3-year rotation is recommended.
White rust
© A. M. Varela
General Information and Agronomic Aspects
Geographical Distribution of Spinach in Africa
Spinach is cultivated worldwide in temperate areas and in the cooler parts of the tropics.

Spinach is an important green leafy vegetable in temperate climates. Leaves are eaten raw or cooked. Tender young leaves can be added to salads, older leaves are cooked and used in soups etc.













Nutritive Value per 100 g of edible Portion
Raw or Cooked Vegetable Food
Energy
(Calories / %Daily Value*)		 Carbohydrates
(g / %DV) 		Fat
(g / %DV) 		Protein
(g / %DV) 		Calcium
(g / %DV) 		Phosphorus
(mg / %DV) 		Iron
(mg / %DV) 		Potassium
(mg / %DV) 		Vitamin A
(I.U)		 Vitamin C
(I.U)		 Vitamin B 6
(I.U)		 Vitamin B 12
(I.U)		 Thiamine
(mg / %DV) 		Riboflavin
(mg / %DV) 		Ash
(g / %DV)
Spinach cooked 23.0 / 1% 3.7 / 1% 0.3 / 0% 3.0 / 6% 136.0 / 14% 56.0 / 6% 3.6 / 20% 466.0 / 13% 10481 IU / 210% 9.8 / 16% 0.2 / 12% 0.0 / 0% 0.1 / 6% 0.2 / 14% 1.8
Spinach raw 23.0 / 1% 3.6 / 1% 0.4 / 1% 2.9 / 6% 99.0 / 10% 49.0 / 5% 2.7 / 15% 588.0 / 16% 9376 IU / 188% 28.1 / 47% 0.2 / 10% 0.0 / 0% 0.1 / 5% 0.2 / 11% 1.7
*Percent Daily Values are based on a 2000 calorie diet. Your daily values may be higher or lower, depending on your calorie needs.


Climatic conditions, soil and water management:
Optimum growing temperatures are 15-20°C. Vegetative growth is retarded by temperatures above 27°C. It does not suit the lowlands and grows best where the temperature varies between 10 and 20°C or above 2000 m altitude. It is frost resistant. Soils should be light in texture, well-drained, rich in organic matter and with a pH 6-7.5 (EcoPort).

Varieties
  • "Early Hybrid No. 7": It is an upright, compact and prolific plant. The leaves are dark green, semi-savoyed, and comparatively large with short petioles. It is early maturing and highly productive. It is tolerant to downy mildew and has a very good regeneration ability.
  • "Bloomsdale Long Standing": It is an upright compact plant. It has thick fleshy leaves, which are dark green, savoyed, large and with very long petioles. It is vigorous and an exceptionally long standing variety.
  • "Giant Noble": It is a dwarf plant, fast growing but produces moderate yields. The leaves are smoth, thick, mid-green with short petioles.
  • "King of Denmark": It is a spreading plant, very prolific and vigorous. The leaves are smooth, thick, mid-green, medium sized with long petioles.
  • "New Zealand Spinach": It is a hardy, low spreading, branching plant. It has numerous leaves, which are triangular, thick, fleshy, dark green and are smaller than other varieties. The seeds are large. Prickly, and germinate slowly. It does well in hot, dry climates. It produces large amounts of greens over a long period hence best suited for kitchen gardens.


Propagation and planting
Transplants are not used commercially, but are good for home gardens. All commercial production is direct seeded with little or no thinning. The seed is either broadcast or sown in rows on wide beds. There should be 5-15cm in between plants in the row. The distance between rows should be 30- 90cm. Spinach seeds need consistent soil moisture for proper germination (University of Georgia).

Husbandry
In temperate areas two types of spinach are recognised, the round seeded type, usually sown in the spring and harvested in the summer, and the hardier prickly seeded type sown end of summer or beginning of fall for use in the winter and spring. Spinach needs high doses of N and K as well as a regular water supply throughout the season for optimum yield and quality. Summer crops may be intercropped with other vegetables to benefit from shade (CAB 2006).

Harvesting
Whole plants with 8-10 leaves are harvested, the roots are cut one cm below the plant base and the product is sold in bundles of 10-15 plants (CAB 2006).
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Fresh Quality Specifications for the Market in Kenya
The following specifications constitute raw material purchasing requirements.
© S. Kahumbu, Kenya

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Information on Pests

Green peach aphid (Myzus persicae)

It is a very detrimental insect to spinach. It can transmit diseases that can wipe out large portions of the crop. Aphids and leafminers cause the most serious damage on the crop (University of Georgia). The aphid is pale yellowish in color and small. It lives mainly on the underside of leaves and therefore hard to control.

Aphids
Aphids (Myzus persicae). Adult wingless females are oval-bodied, 1-2 mm in body length, of very variable colour.

© Magnus Gammelgaard
More Information on Aphids
What to do:
  • Conserve natural enemies. Parasitic wasps and predatory insects, including lady bird beetles, damsel bugs, lacewings, and hover fly larvae are important in natural control of aphids. For more information on natural enemies click here
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Information on Diseases

Downy mildew (Peronospora spinaciae / Peronospora farinosa)

This fungus is distributed worldwide. It causes leaf spotting that detracts from the quality and appearance. Leaf spots begin as indefinite yellowish areas on the upper leaf surface. A mat of grey to violet mould develops on the corresponding lower surface. With time under cool, wet conditions, the spots enlarge until the whole turns black and dies. The fungus increases profusely in high humidity. The spores can overseason in mild climatesin living spinach, in seeds and in the soil.

Downy mildew
Downy mildew on cabbage

© A.M. Varela, icipe
More Information on Downy mildew
What to do:
  • Use resistant varieties (e.g. "Early Hybrid 7")
  • Use certified disease-free seeds. If using own seeds, treat seeds with 500°C for 25 minutes.
  • Practice at least a 3-year rotation and plant in well-drained soil.

Bacterial soft rot (Erwinia carotovora)

It is one of the most important diseases. Its symptoms include water soaked tissue and muddy-green or greasy appearance of leaves. Rapid decay occurs and the tissue becomes wet and mushy. This bacterium is found in the soil and in plant debris. It can enter into the plant through mechanical injury, insect injury, disease lesions and other skin punctures.


Bacterial soft rot. Note slimy rot (whitish) of the centre of the cabbage head

© A. M. Varela, icipe



What to do:
  • Practice rotation with maize, beans, small grains and grasses.
  • Care at harvesting and handling to avoid bruising.
  • A storage temperature just above freezing (0°C) and a relative humidity below 90% does much to reduce soft rot losses.
  • Storage rooms, dump tanks and boxes should be disinfected each season with copper sulfate.

Fusarium wilt (Fusarium oxysporum f. sp. spinaciae)

It is a wilt that is caused by a fungus. Plants can be affected anytime after the tree-leaf stage. Foliage loses its green luster, gradually wilts and turns yellow, beginning with the oldest leaves. The fungus is soil-borne and seed-borne. It commonly occurs where temperatures are fairly high. It can live in the soil indefinitely and there rotation is not effective in its control.

Fusarium wilt
Wilting of okra plant due to fusarium wilt

© A.M. Varela & A.A.Seif, icipe


More Information on Fusarium wilt
What to do:
  • Use resistant varieties where available.
  • Use certified disease-free seeds.

White rust (Albugo occidentalis)

It is a fungus that causes white blister-like pustules on the underside of leaves. They are filled with white spores and the surrounding tissue turns brown and dies. The fungus favors clear, warm, and dry days with cool nights.

White rust
White rust on kales. Note pustules on the lower side of the leaf

© A. M. Varela
What to do:
  • Use resistant varieties where available.
  • Use certified disease-free seeds.
  • A 3-year rotation is recommended.

Cucumber Mosaic Virus (CMV)

It is transmitted by the green peach aphids. Symptoms begin as a mottling of the younger inner leaves, which later change to a yellow colour. The symptoms gradually appear on outer leaves, which also change to yellow. The affected leaves curl and wrinkles. Severely affected leaves die. If a plant is affected at the seedling stage, its growth is stunted. The dwarfing, yellowing, corrugation and leaf death are conspicuous symptoms of the disease different from other diseases attacking spinach.

Intensity of the virus increases under long days and intense light. This virus affects, in addition to spinach, a wider group of vegetables, flowers, weeds and ornamentals than any other virus. At least 34 plant families are included as hosts.



What to do:
  • Use resistant varieties (e.g. "Early Hybrid 7").
  • Control aphid vectors throughout the growing season.
  • Control weeds.
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Information Source Links
  • CAB International (2005). Crop Protection Compendium, 2005 edition. Wallingford, UK www.cabi.org
  • East African Seed Co. Ltd. Africa's Best Grower's Guide www.easeed.com
  • Ministry of Agriculture and Rural Development, Kenya and Japan International Cooperation Agency, (2000). Local and Export Vegetables: growing Manual. Printed by Agricultural Information Resource Centre, Nairobi, Kenya
  • Nutrition Data www.nutritiondata.com.
  • Plants For A Future, 1996-2003. www.pfaf.org
  • Sherf, A. F. and Macnab, A. A. (1986). Vegetable Diseases and Their Control. John Wiley & Sons, Inc. ISBN: 0-471-05860-2.
  • University of Georgia, College of Agricultural and Environmental Sciences, Department of Horticulture
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Contact Information
  • Corner Shop cls@mitsuminet.com
  • Food Network East Africa Ltd info@organic.co.ke 0721 100 001
  • Green Dreams admin@organic.co.ke 0721 100 001
  • Kalimoni Greens kalimonigreens@gmail,com 0722 509 829
  • Karen Provision Stores karenstoresltd@yahoo.com 020885552
  • Muthaiga Green Grocers
  • Nakumatt Supermarket info@nakumatt.net 020551809
  • Uchumi Supermarket
  • Zuchinni Green Grocers 0204448240
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Spinach (S. oleracea) seedlings grown as field crop.
© AgrEvo. Reproduced from the Crop Protection Compendium, 2006 Edition. © CAB International, Wallingford, UK, 2006.
Predator
Animal that attacks and feeds on other animals, such as an insect (e.g. ladybird beetle), bird or spider feeding on pest insects.
Fungi
Occurring worldwide, most fungi are largely invisible to the naked eye, living for the most part in soil, dead matter, and as symbionts of plants, animals, or other fungi. They perform an essential role in all ecosystems in decomposing organic matter and are indispensable in nutrient cycling and exchange. Some fungi become noticeable when fruiting, either as mushrooms or molds.

Fungi are responsible for a range of serious plant diseases such as blight, grey mould, bunts, powdery mildew, and downy mildew. Crops of all kinds often suffer heavy losses.

Fungal plant diseases are usually managed with applications of chemical fungicides or heavy metals. In some cases, conventional breeding has provided fungus resistantcultivars.

Besides combatting yield losses, preventing fungal infection keeps crops free of toxic compounds produced by some pathogenic fungi. These compounds, often referred to as mycotoxins, can affect affect the immune system and disrupt hormone balances. Some mycotoxins are carcinogenic.