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Cabbage/Kale, Brassicas

Scientific name:

Brassica spp.

Order/Family:

Capparales: Cruciferae/Brassicaceae

Local names:

Kenya: Sukuma wiki (Swahili)

Common names and related Brassicas:

Cabbage, kale, choumolea, Chinese cabbage, cauliflower, rape, broccoli, Brussels sprouts, kohlrabi, savoy, turnip.

Pests and Diseases:

Alternaria leaf spot Aphids Bacterial soft rot Bagrada bug Black rot Broomrape Cabbage looper Cabbage moth Cabbage webworm Cauliflower Mosaic Virus Cercospora leafspots Clubroot Cutworms Damping-off diseases Diamondback moth (DBM) Downy mildew Leafmining flies (leafminers) Powdery mildew Sawflies Snails (Giant East African Snail) Thrips Turnip Mosaic Virus (TuMV) White rust Whiteflies

General Information and Agronomic Aspects				Other diseases
Fresh Quality Specifications for the Market in Kenya				Information Source Links
Information on Pests				Contact Information
Information on Diseases

General Information and Agronomic Aspects

Geographical Distribution of Cabbage/Kale and Brassicas in Africa

Brassicas constitute the majority of cultivated Cruciferae in eastern and southern Africa. The main brassicas grown in the region include:

Cabbage (Brassica oleracea L. var. capitata)
Kale (sukumawiki) or choumolea (B.o. acephala)
Chinese cabbage(B. campestris chinensis/pekinensis)
Cauliflower (B.o botrytis)
Rape B.carinata (indigenous), and B.napus, (exotic type).

Other brassicas grown in the region are broccoli, Brussels sprouts, kohlrabi, savoy and turnip.
Also grown in the region are radish (Raphanus sativus L. var. hortensis) and horseradish (Armoracia rusicana Gaertn.)

These vegetables are grown mainly for the local market. They are valuable as sources of vitamins and minerals, as well as a source of cash for smallscale farmers in rural and peri-urban areas. However, production is often constrained by damage caused by a range of pests (insects, diseases, nematodes and weeds).
The range of pests attacking the different brassicas is similar, but the relative importance of individual pest species varies between the different crops.

Cabbage is mainly sold fresh or as processed canned product. Processed products include those that are treated in vinegar, or fermented such as sauerkraut or kimchi. Fresh cut or lightly processed products include coleslaw and ready-to-eat salad mixes that contain shredded cabbage. Consumers generally prefer fresh green cabbage, when available, to stored cabbage. Much of the stored cabbage is grown for processing.

Nutritive Value per 100 g of edible Portion

Raw or Cooked Cabbage/Kale /Brassica

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)

Broccoli cooked

35 / 2%

7.2 / 2%

0.4 / 1%

2.4 / 5%

40.0 / 4%

67.0 / 7%

0.7 / 4%

293 / 8%

1548 IU / 31%

64.9 / 108%

0.2 / 10%

0.0 / 0%

0.1 / 4%

0.1 / 7%

0.8

Brussel Sprouts cooked

36.0 / 2%

7.1 / 2%

0.5 / 1%

2.5 / 5%

36.0 / 4%

56.0 / 6%

1.2 / 7%

317 / 9%

775 IU / 15%

62.0 / 103%

0.2 / 9%

0.0 / 0%

0.1 / 7%

0.1 / 5%

0.9

White Cabbage cooked

23.0 / 1%

5.5 / 2%

0.1 / 0%

1.3 / 3%

48.0 / 5%

33.0 / 3%

0.2 / 1%

196 / 6%

80.0 IU / 2%

37.5 / 62%

0.1 / 6%

0.0 / 0%

0.1 / 4%

0.0 / 0%

0.6

Red Cabbage cooked

29.0 / 1%

6.9 / 2%

0.1 / 0%

1.5 / 3%

42.0 / 4%

33.0 / 3%

0.7 / 4%

262 / 7%

33.0 IU / 1%

34.4 / 57%

0.2 / 11%

0.0 / 0%

0.1 / 5%

0.1 / 4%

0.6

Savoy Cabbage cooked

24.0 / 1%

5.4 / 2%

0.1 / 0%

1.8 / 4%

30.0 / 3%

33.0 / 3%

0.4 / 2%

184 / 5%

889 IU / 18%

17.0 / 28 %

0.2 / 8%

0.0 / 0%

0.1 / 3%

0.0 / 1%

0.7

Chinese Cabbage cooked

14.0 / 1%

2.4 / 1%

0.2 / 0%

1.5 / 3%

32.0 / 3%

39.0 / 4%

0.3 / 2%

225 / 6%

967 IU / 19%

15.8 / 26%

0.2 / 9%

0.0 / 0%

0.0 / 3%

0.7

Cauliflower cooked

23.0 / 1%

4.4 / 1%

0.5 / 1%

1.8 / 4%

16.0 / 2%

32.0 / 3%

0.3 / 2%

142 / 4%

12 IU / 0%

44.3 / 74%

0.2 / 9%

0.0 / 0%

0.0 / 3%

0.1 / 3%

0.6

Kale cooked

28.0 / 1%

5.6 / 2%

0.4 / 1%

1.9 / 4%

72.0 / 7%

28.0 / 3%

0.9 / 5%

228 / 7%

13623 IU / 272%

41.0 / 68%

0.1 / 7%

0.0 / 0%

0.1 / 4%

0.9

Kohlrabi cooked

29.0 / 1%

6.7 / 2%

0.1 / 0%

1.8 / 4%

25.0 / 2%

45.0 / 4%

0.4 / 2%

340 / 10%

35.0 / 1%

54.0 / 90%

0.2 / 8%

0.0 / 0 %

0.0 / 3%

0.0 / 1%

1.1

Radish raw

16.0 / 1%

3.5 / 1%

0.1 / 0%

0.7 / 1%

25.0 / 2%

20.0 / 2%

0.3 / 2%

233 / 7%

7.0 IU / 0%

14.8 / 25%

0.1 / 4%

0.0 / 0%

0.0 / 4%

0.0 / 0%

0.5

Turnip Greens cooked

20.0 / 1%

4.4 / 1%

0.2 / 0%

1.1 / 2%

137 / 14%

29.0 / 3%

0.8 / 4%

203 / 6%

7626 IU / 153%

27.4 / 46%

0.2 / 9%

0.0 / 0%

0.0 / 3%

0.1 / 4%

1.1

Turnip Roots cooked

22.0 / 1%

5.1 / 2%

0.1 / 0%

0.7 / 1%

33.0 / 3%

26.0 / 3%

0.2 / 1%

177 / 5 %

0.0 IU / 0%

11.6 / 19%

0.1 / 3%

0.0 / 0%

0.0 / 2%

0.0 / 1%

0.5

*Percent Daily Values (DV) are based on a 2000 calorie diet. Your daily values may be higher or lower, depending on your calorie needs.

Climate conditions, soil and water management

Cabbage is a biennial plant that grows best under full sunlight. The optimum mean temperature for growth and quality head development is 15-18°C, with a minimum temperature of 4°C and a maximum 24°C. Generally, young plants are more tolerant to heat and cold than plants nearing maturity. For seed production cabbage plants need to pass through vernalisation: continous days with temperatures at 1.7-10 °C before they start bolting. Broccoli and cauliflower produce seed without vernalisation.

Cabbage grows well on a wide range of soils with adequate moisture and fertility. Soil pH in the range of 6.0-6.5 is preferred, but cabbage will tolerate a soil pH range of 5.5 to 6.8. Cabbage is a heavy feeder, so to get good yields, proper fertilisation is necessary.

To maintain growth, cabbage requires a consistent supply of moisture, and should as a general rule receive a minimum of 2.5 cm of water per week. Larger quantities may be required when cabbage is grown on sandy soils or when evapotranspiration is high.

Nutrient deficiencies
Growing healthy plants is the best way of avoiding problems. Healthy plants grow on a healthy and well nourished soil with a good texture. Good compost is the best and most balanced soil and plant feed available to farmers. Regardless of soil type, excessive N (nitrogen) can promote second growth and split heads. A high level of nitrogen will also shorten storage life of cabbage and promote pungent odour (strong smells) during cooking.

Combined with high temperatures, excess N (nitrogen) can promote such rapid growth that plants show symptoms of tip burn in susceptible cultivars. Depressed yields, delayed maturity, reduced keeping quality and strong or objectionable flavours are indicative of N deficiency. Like most cruciferous crops, cabbage has a high requirement for boron and molybdenum. Boron deficiency causes yellowing or chlorosis of the youngest leaves and stems, which often starts from the base and extends to the tip, hollow and discoloured inside stems of broccoli and cauliflower, and hollow and/or shrunken roots of turnips.

Rosetting or even death of terminal shoots or buds occurs in extreme cases. The common symptoms of molybdenum deficiency in cabbage include a general yellowing, marginal and interveinal chlorosis, marginal necrosis, rolling, scorching and downward curling of margins usually on older leaves. Compost and well rotted animal manures are good sources of most micronutrients including boron and molybdenum.

Land preparation and management

Prepare land well before transplanting.
Avoid field operations when it is wet. This will help to prevent inadvertent spread of diseases from plant to plant and movement of infested soil within and outside the field.
Keep fields free of weeds. Especially weeds of the brassica family are potential alternative hosts of insect pests and diseases and are nutrient competitors.
Ensure optimal fertilisation. Cabbage has a very shallow root system and is particularly responsive to phosphorus. Where the soil has a low phosphorus content the application of 'Mijingu Rock Phosphate' is recommended.

Propagation and planting

Seedlings:

Practise crop rotation: site seedbeds on land not previously under crucifers, and preferably away from old crucifer fields.
Use clean wooden trays to raise seedlings, use mixture of compost and top soil or forest soil for raising seedlings.
Heat soil in the seedbed: place plenty of crop trash or straw and burn for at least 30 min, and after cooling, mix the soil with compost in equal proportions.
Use certified disease free seed of resistant/tolerant cultivars.
Mulch seedlings in the seedbed, if possible.
Do not over water seedlings in the seedbed: water seedlings early in the morning and thin out seedlings to avoid plant congestion in the seedbed. Excessive watering is conducive to damping-off diseases, and extended wetness of seedlings favours development of foliar diseases.

Seeds:
Treating own seed in hot water to prevent seed-borne diseases such as black rot, black leg, black spot and ring spot is recommended where these diseases have previously appeared Hot water treatment of seeds helps reduce the seed-borne pathogens. However, the specified temperature and time interval should be strictly followed in order to maintain seed viability. Use a good thermometer or better ask for assistance from qualified personnel from your local agriculturist office.
Recommended temperature and time for hot water treatment for broccoli, cabbage, cauliflower, kale kohlrabi and turnip is 50°C (122 F) for 30 minutes.
For more details on hot water treatment click here

Varieties grown in Kenya

Seeds of the varieties given below are readily available from seed companies and vendors in Kenya. For information on seed companies contact Horticultural Crops Development Authority. (md@hcda.or.ke www.hcda.or.ke +2542088469)

Cabbage varieties
"Globe Master F1 Hybrid"

This is a high yielding hybrid cabbage with wide adaptability to different conditions. It has nice blue green colour and globe shaped with short core. It is highly tolerant to black rot and Fusarium yellows. It grows up to 2.5 kg 75 days after transplanting but can grow up to 3.5 kg under optimum conditions, especially in warm areas.

"Gloria F1 Hybrid"

It is a proven best F1 hybrid in fresh market and processing industry. Well adaptable to various climatic conditions withstanding high temperatures. It is a mid-early maturing variety, ready for harvesting in 90 days after transplanting. Head weighs about 4 kg with solid blue green colour and thick waxy layer and has strong rooting, medium resistance to Fusarium yellows. Has good resistance to splitting and keeps well after harvesting.

"Blue Dynasty F1":

It is adapted to a wide range of agroecological zones. It is heat tolerant. Maturity is about 80-85 days afterplanting. Head weight is about 4-6 kg of blue green colour. Yield potential is about is 45-68 t/acre. It is resistant to black rot, ring rot and diamondback moth.It has a good transport quality.

"Victoria F1"

It is widely accepted in various markets. Its very fast growing with maturity period about 70-75 days from transplanting. It uniformly matures. It has compact heads each weighing between 4-5 kg. Its yield potential ia about 45-56 t/acre. It transports well.

"Oxylus F1"

It is adapted to a wide range of agroecological zones. It has compact heads weighing about 4-5 kg each. Yield potential ranges from 45 to 56 t/acre. Its maturing period is about 70-75 days from transplanting and matures uniformly. It is heat resistant and also resistant to alkalinity. It transports well.

"Green Coronet F1 Hybrid"

Medium-large, semi-upright plant grows well in medium hot to cold areas, with deep green, oblate head growing up to 4 kg under optimum conditions. Medium-early in maturity and takes about 75-80 days after transplanting. Has execellent field holding capacity and will last long in the field before bursting.

"Riana F1 Hybrid"

This is an all-round variety that is heat and cold tolerant. It produces round, blue-green compact heads weighing about 2.5 kg. It does well both in temperate, subtropical and tropical zones. It is tolerant against black rot and tip burn. It matures in 90-100 days after transplanting and has excellent non-bursting quality round head after maturity.

"Super Master F1"

Widely adaptabe hybrid, produces round to flat-round, bluish green compact head weighing 4-5 kg. It has an excellent field holding capacity and can stand in the feld for long without bursting. Matures in about 80-85 days after transplanting. It is resistant to Fusarium yellows, Alternaria, medium to high resistance to black rot and diamondback moth.

"Santar F1"

It has a very firm compact, globe-shaped head, which is blue green in colour. The weight is 4-6 kg. It matures in 80-90 days after transplanting. It has good resistance especially to black rot and diamondback moth. It has good transportation ability.

"Field Winner F1 Hybrid"

It takes about 80 days from transplanting to harvest. Head is semi-flat and weighs about 4 kg. It is resistant to black rot. It has a sweet taste.

"CPI"

It is a hybrid cabbage. It has green heads. The weight is 3-5 kg. The shape is round. It matures in 70-80 days after transplanting. It has a good field holding capacity since it does not burst easily. It has a sweet flavour therefore very ideal for salads. It is tolerant to Fusarium and black rot.

"Pruktor F1 Hybrid"

It takes about 80 days from transplanting to harvest. Head is high and round. The head weighs about 5 kg. It has high resistance to black rot. It has shown considerable resistance to diamondback moth.

"Hero F1 (Sokoni)"

This is a Chinese cabbage. It is an early maturing hybrid, which is ready 65 days after transplanting. It has high tolerance against some virus diseases and black rot. It is strong against heat and cold, vigorous and easy growing. It produces medium sized green head with excellent internal white colour, weighing 2 kg with good transportation and storage ability. It is suitable for high density planting due to its compact round leaves and standing plant habit.

"Chihili"

It is open-pollinated Chinese cabbage. It produces uniform pale green, loaf-like heads, grows vigorously and the core is white. It is prone to bolt at low temperature. It is a widely adaptable cabbage with a slightly tangy flavour, popularly used in salads. Over the years the variety has become very popular in Tanzania.

"Red Dynasty F1"

It is high in anthocyanin with compact heads weighing about 4-5 kg each. Its yield potential ranges from 45 to 56 t/acre. Its early maturing taking about 70-75 days from transplanting. It is resistant to black rot and diamondback moth. It transports well.

"Ruby Perfection F1 Hybrid"

This is a vigorous, easy growing and heavy yielder with a deep red head weighing about 2 kg. Very uniform maturity, is late busting therefore has a long harvest period. It has strong tolerance against heat and cold with ability to form heads at low temperatures. It matures in about 80 days after transplanting.

"Copenhagen Market"

It is open-pollinated. It is the most popular amongst the ball-headed cabbages and a great favourite for the both home and market gardeners in Kenya at present. The heads are uniform round, firm, medium sized and weighing about 2-3 kg. The plant is short-stemmed and rather small, and can be spaced closer. It is early maturing, approx. 60-70 days after transplanting. It is rather sensitive to splitting and should not be left in the field for too long after maturity. It is a highly dependable and productive variety.

"Glory of Enkhuizen"

It is open-pollinated. A nice and attractive variety which is presently more popular in East and Central Africa. The plant is low and relatively wide. The heads are medium large, flat round, green, firm and sweet (sweeter than any drumhead type). It matures after about 12 weeks with the head weighing about 3.5 kg. Harvesting is spread for about 3 weeks thus market supply can be over a long period.

"Prize Drumhead"

It is open-pollinated. A very late maturing variety in about 18-19 weeks. The heads are flat, solid, largest is about 30 cm in diameter and can weigh more than 5 kg. Plants are spreading type and very large, A hardy variety which produces high yields.

"Sugar Loaf"

It takes about 75 days from transpling to harvest. Head is conical and weighs about 2 kg. Prefers cool conditions. Its suitable for areas with well distributed moderate to heavy rainfall. It should be planted in well drained soils.

Broccoli varieties
"Calabrese"

An early broccoli with medium large and compact heads with exquisite flavour. An abundance of fleshy stalked flowering shoots are produced over a long period. A nice variety with fine quality.

"Heritage F1"

It is ideal for cool climatic zones. It is dome shaped with lightly beaded florets. Maturity period is about 80 days from transplanting. Potential yield is about 8 t/acre. It has intermediate resistance to downy mildew.

"Dandy Early No. 32 F1"

This is an early, vigorous variety tolerant to black rot and downy mildew. It can withstand high temperatures. The head is firm, dome-shaped about 10-12 cm wide and 6 cm high.It matures 92 days after planting and harvesting continues for about 10 days.

"Early Green F1"

It is early maturing with good quality heads. It has a typical single head and no side shoots. The heads are solid, regular shaped. It is mushroom shaped with uniform bluish green colour. The heads ripen evenly and harvesting starts 85 days after germination lasting 10-12 days. The variety responds well to heavy watering and thrives at high altitudes.

Cauliflower varieties
"Snowball"

This is a widely adaptable, mid-early variety. The curd is well covered by straight leaves, head is rather round, firm and white weighing approximately 1 kg. It is a popular kitchen garden variety.

"Snow Crown F1 Hybrid"

This is a very early maturing variety in about 70 days after transplanting. Plants are medium-upright with excellent curd quality. The head is white and semi-dome shaped. It is a high yielder with strong tolerance to heat and cold and a very popular hybrid for its easy growing. Head weighs about 850 gm.

"Extra Early Six Weeks"

It takes 65 days from transplanting to harvest. Head is round and firm. Average head weight is about 1.2 kg. It is more exacting in climatic requirements. High temperatures are not favourable. Soils should be clean and high in organic matter.

"Kibo Giant"

It takes about 75 days from transplanting to harvest. Head is snow white, compact and fined grained. Average head weight is about 1 kg. It has large wrapper leaves.

"Fremont F1"

It is ideal for cool climatic zones. Its fast growing with a maturity period of about 90-100 days from transplanting. It has attractive white coloured curd. Yield potential of 7-9 t/acre. Avreage head weight is 600-800 grams.

"Italian Giant"

It takes 75 days from transplant to harvest. It has a white, smooth and firm heas. High temperatures are not favourable for its growth.

"Wallaby"

It takes 80-85 days to harvest from transplanting. Head is snow white, compact and fine grained.

Kale varieties
"Thousand Headed"

This is a continuous growing and hardy crop that is tolerant to cold temperatures. It can stay in the field for a long time, therefore, giving a higher yield. It has a thick stem with big leaves that are dark green, smooth and attractive. It matures between 90-100 days. It can also be used as fodder for animals. It is easily digestable and easy to cook.

"Southern Georgia"

It is a very popular seed variety grown across Africa. It has been developed to give high yields while up to 6 months before flowering thus profitable to farmers.The leaves are well flvoured and easy to cook. It is popular in the local market. It is adapted to hot areas. It is hardy and resistant to black rot.

"Marrow Stem"

The variety has dark green leaves and flavour and little fibre. It is vigorous, medium tall with finely curled leaves which are less prone to bird damage.

Husbandry

Cabbage is often planted on raised beds that are shaped from bare soil after ploughing and disking. This technique is popular on level soils where furrow irrigation is also used. Bed culture is also used in other areas to improve soil drainage or when plastic mulch is used. The trend has been toward increased use of conservation tillage, particularly on steeply-sloping soils prone to erosion. Producing cabbage using conservation tillage reduces the number of field passes by farm equipment, thus reducing compaction, preserving equipment and conserving fuel.
Conservation tillage systems cause minimum disturbance to the soil after the previous crop has been harvested. Crop residues are left in the field to reduce soil erosion, conserve moisture, inhibit weed growth, and act as green manure. There are several types of conservation tillage in use, as well as combinations of conservation and conventional tillage. However, in disease management, crop residues must be either removed from the field and destroyed or deeply ploughed to reduce sources of disease infection and spread.
Advantages of conservation tillage for cabbage production include less machinery, labour and fuel, as well as reduced soil erosion and compaction. Disadvantages of conservation tillage include lower soil temperatures, slower germination and emergence when direct sowing is used, slower early growth, delayed competition with weeds, higher incidence of root diseases, heavier crop residue, the possibility of more difficult planter operation, weed spectrum changes, and potential increase of soil insect pests or insects that spend part of their life cycle in the soil (e.g. cutworms, thrips, leafmining flies, grubs). Cultivation exposes these pests to desiccation by the sun heat and to predation by natural enemies

Intercropping

Intercrop brassica crops with trap crops or repellent plants, to reduce pest infestation. Tomato reportedly repels diamondback moth and Indian mustard acts as a trap crop. Intercropping brassicas with spinach, beans or dill reportedly reduces aphid infestation.
Tomatoes when planted 14 days before cabbage reduce the incidence of and damage by diamondback moth. Cabbage intercropped with tomato, coriander or garlic, combined with the application of neem seed kernel extract protects plants from diamondback moth in the field. Indian mustard, Chinese cabbage, and radish are good trap crops for controlling cabbage webworm, flea hopper, and mustard aphid when planted in every 15 rows of cabbage. The mustard row is either in the outermost or in the middle row to avoid caterpillars being blown by wind into the cabbage plants. To control cabbage head caterpillar, Indian mustard should be planted 12 days before transplanting cabbage. Do not plant cabbage where members of the cabbage family have been grown for 3 consecutive years to avoid serious problems of pests and diseases (especially soil borne diseases).

Monitoring
It entails regular field observation during the crop production cycle for pests, diseases, weeds and general aspects of crop health like nutrition and water requirements. Field monitoring methods are virtually the same, but most importantly, in the process is problem recognition. Thus it is very important to be able to identify pests and diseases and to differentiate a pest from a beneficial insect, a pest damage from disease damage, and a pest or disease damage from nutritional problems or physiological disorders.

Monitor fields regularly for pest and disease occurrence. Early detection of pests and diseases is important as outbreaks are easier controlled in the initial stages. Cutworms and other insects can do a lot of damage in just 1 or 2 days.
Scout for caterpillar presence: feeding damage and caterpillar excrement give an indication of their activity. Scouting can be done by walking in a zigzag pattern through the field.
Check for aphids and whether parasitised aphids (mummies) and natural enemies such as ladybird beetles and lacewings are present. Since aphid populations are often clustered, all portions of the field should be checked. For more information on natural enemies click here.
Scout for the major brassica diseases (refer to major diseases below).

Harvesting

Cabbage is often hand-harvested when heads are firm to the touch but before cracking begins. With hand harvesting, a given field is harvested two to four times to obtain heads of uniform size and maturity. Only one to three harvests of hybrid cultivars are required because of their greater uniformity. Use of uniform transplants and consistent growing conditions also helps reduce the number of harvests. Yields will vary with the season of production, cultivar, and production system used. With proper management, cabbage can produce 10-12 tons per acre. Generally, most fresh markets prefer heads that weigh on average 1-2,5kg. For processing into coleslaw or sauerkraut, or for long-term storage, larger-headed cultivars are used.

Field sanitation
Remove crop residues immediately after harvest and also remove volunteer plants from the field.

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Fresh Quality Specifications for the Market in Kenya

The following specifications constitute raw material purchasing requirements

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Information on Pests

The major pest constraints of brassicas in Africa were identified as the diamondback moth (DBM), cabbage aphids, cabbage webworm and Bagrada bugs.

Aphids Several species of aphids attack brassicas in East Africa: The cabbage aphid (Brevicoryne brassicae) The false cabbage aphid (Lipaphis erysimi) The green peach aphid (Myzus persicae) In particular the cabbage aphid is a major pest in the region. Cool, dry weather is most favourable for aphid development. Large numbers of aphids may kill small plants. Their feeding can distort leaves of older plants and causes leaf curl. Often, the most serious problem associated with aphids is virus transmission. The cabbage aphid and the false cabbage aphid are vectors of virus diseases such as cabbage black ring spot, cabbage ring necrosis, and mosaic diseases of cauliflower, radish and turnip.	Cabbage aphids Colony of the cabbage aphid (Brevicoryne brassicae) on kales. Cabbage aphids are about 1.5 - 2.5mm in size. © A. M. Varela, icipe Cabbage ap… Cabbage ap… Cabbage ap… Cabbage ap… More Information on Aphids
What to do: Aphid colonies in the heads of cabbage are almost impossible to remove before marketing. Natural enemies can provide control, but they usually do not build up fast enough to keep heavy aphid populations below damaging levels. Extensive use of broad-spectrum insecticides like pyrethroids might induce resistance development in aphids and will eliminate natural enemies. For more information on natural enemies click here. Insecticidal soaps provide control, and spot sprays of pyrethrum or neem can prevent build up of large populations.

Sawflies (Athalia spp) Sawflies are sporadic but serious pests of brassicas. The cabbage sawfly (Athalia sjostedti) has been reported as a major pest in Tanzania. Sawfly adults are wasps with dark head and thorax, bright yellow abdomen, and two pairs of membranous wings. They are about 1 cm long. Eggs are laid singly inside the leaf. Larvae are oily, black or greenish in colour with a swollen part just behind the head, which makes them appear humped. They look very similar to caterpillars, but they have 6 to 9 pairs of prolegs (abdominal legs), whilst caterpillars have 5 pairs or less. Larvae measure up to 2 cm when fully grown. Larvae eat the blades of leaves leaving just the main veins. They drop from the plant to pupate in the soil.	Sawflies larvae Sawfly larva (Athalia spp) and damage on horseraddish © A. M. Varela, icipe Sawflies l… Sawflies a…
What to do: Destruction of wild plants of the family of cabbages in the vicinity of the crop. Ploughing in of volunteer plants at the end of the season helps reduce sawfly populations. Manual collection and destruction of larvae is feasible when there are few sawflies on the crop.

Diamondback moth (DBM) (Plutella xylostella) It is a serious pest of brassicas and attacks all Brassica species. A full grown diamondback caterpillar is about 1 cm long.	Diamondback moth Diamondback moth damage on cabbage © A. M. Varela, icipe Diamondbac… Diamondbac… Diamondbac… Diamondbac… More Information on Diamondback moth (DBM)
What to do: To control DBM in small farms, cover seedlings with covers (fine nylon mesh) to prevent moths from laying eggs on the leaves and or next to the plant. Intercropping brassicas with trap plants such as Indian mustard, and repellent plants such as tomato, reportedly reduces DBM infestation in cabbage. In the case of Indian mustard, control measures are directed at DBM on the trap crop. When intercropping with tomato, the cabbage crop is planted 30 days after tomato. Biological control of DBM using parasitoid wasp Diadegma semiclausum has proven very effective in the highlands of Kenya, Tanzania and Uganda. Botanicals such as neem-based pesticides are very effective for control of DBM. Also Bt sprays are effective against DBM. For more information on Bt click here

The cabbage looper (Trichoplusia ni) The cabbage looper is a green caterpillar with faint white stripes along the body. Caterpillars are about 3.5 to 4 cm long when fully-grown. As they move, they arch their back in a looping fashion, hence the common name looper. Larvae (caterpillars) chew holes in the leaves, and larger caterpillars consume great amounts of plant material. On cabbage they eat into the heads, reducing the marketability of the produce. The adult is a moth about 2.5 cm in length and mottled, greyish-brown.	Cabbage looper, caterpillar Cabbage looper on cabbage. The first instar larvae is white and almost clear with a black head capsule. Later instars are green with a thin white line on each side. Mature larvae reach 3 to 4 cm in length. © A.M. Varela, icipe Cabbage lo… Cabbage lo… More Information on Cabbage looper
What to do: Conserve natural enemies. These caterpillars are attacked by a large numbers of natural enemies, including parasitic wasps and flies. Birds and bats feed on the adults (moths). Pick caterpillars by hand and destroy them. When control is necessary use biopesticides such as neem-based products or Bt. Neem products control cabbage looper by interfering with the growth of the young caterpillar. Bt and neem should be applied when caterpillars (larvae) are still in the early growth stages. For more information on neem click here. For more information on Bt click here.

The cabbage webworm (Hellula undalis) Caterpillars are 1.5 cm when fully-grown, creamy-white in colour with brown stripes along the body and a brown head. Caterpillars feed on leaves, petioles, growing points, and stems.	Cabbage webworm caterpillar Cabbage webworm caterpillar (Hellula undalis) and damage on a kale leaf. © A. M. Varela, icipe Cabbage we… Cabbage we… Cabbage we… More Information on Cabbage webworm
What to do: Use neem-based products and Bt.

The cabbage moth (Crocidolomia pavonana (=binotalis)) Cabbage moth larva: when fully grown is about 1.6-1.9 cm long. Larvae pupate in the soil. The pupal stage lasts about 10 days. It is primarily a pest of brassicas and is occasionally an important pest of cabbage and kales. Caterpillars are found in groups. Young caterpillars chew off top leaf surfaces, while older caterpillars feed under a web of silk on young leaves, petioles and growing point of the plant, often damaging it entirely.	Cabbage moth larvae When the cabbage moth larvae is fully grown it is 1.6-1.9 cm long. The larvae move to pupate in the soil. The pupal stage lasts about 10 days. © Ooi P. Courtesy of Ecoport (www.ecoport.org) Cabbage mo… Cabbage mo… Cabbage mo… More Information on Cabbage moth
What to do: Spray with neem extracts and Bt.

The Bagrada bug (Bagrada hilaris) It is typically shield-shaped, 5-7mm long and 3-4mm wide. The upper surface has a mixture of black, white and orange markings. Feeding by sucking by both adults and nymphs causes damage to leaves, which wilt later and dry. A heavy attack on young plants generally results in death of the plant.	Bagrada bug The adult bagrada bug (Bagrada hilaris) is typically shield-shaped, 5-7mm long and 3-4mm wide. The upper surface has a mixture of black, white and orange markings. © F. Haas, icipe Bagrada bu… Bagrada bu… Bagrada bu… More Information on Bagrada bug
What to do: Crop hygiene including destruction of weeds of the family Cruciferae prevents population build-up. Remove bugs by hand.

Cutworms (Agrotis spp) Cutworms cut the stem of plants below the soil surface. The damaged plant wilts and withers. First instars are 0.7-1 cm, later instars are 3.5-5 cm long.	Cutworm Cutworm (Agrotis sp.) © A.M. Varela, icipe More Information on Cutworms
What to do: Cutworm damage is usually minor and does not warrant control measures. When damaged plants are detected, the cutworms normally can be found near the damaged plant and can be removed by hand.

Leafmining flies (Lyriomiza brassicae) Leafmining flies are small about 1.3-1.6 mm in length. Maggots of leafmining flies cause mines while feeding within the leaf. Small, individual leafminers do not produce much damage, but when larvae occur in large numbers, entire leaves can be eaten out. Heavy attacks weaken seedlings and may result in dying off the young plants.	Leafminer Mines cause by maggots, and a pupa of leafminer flies (Lyriomiza brassicae) © A.M. Varela, icipe More Information on Leafmining flies (leafminers)
What to do: Leafminers are usually well controlled by existing natural enemies, particularly parasitic wasps. However, this balance can be disrupted by the use of non-selective pesticides.

Thrips (Thrips tabaci Frankliniella spp) Thrips feeding on cabbage cause rough bronzed blisters on leaves inside the cabbage head. hey are less than 2 mm long. Thrips attacks are not common on brassicas in the eastern and southern Africa region.	Thrips Thrips damage on lower surface of cabbage leaf. Note rough brown patches and small dark spots (thrips faeces) © A.M. Varela, icipe More Information on Thrips
What to do: Plough and harrow before transplanting. This can be useful in reducing thrips attacks by killing pupae in the soil. Conservation of natural enemies, such as predatory bugs, predatory mites and predatory thrips are important.

Whiteflies (Bemisia tabaci, Trialeurodes vaporariorum and Aleyrodes proletella) Whiteflies feed on brassicas. Adult whiteflies are about 1 mm long. In East Africa whitefly populations on brassicas usually do not build up to such an extent that control measures are required.	Cabbage whitefly Adults and eggs of the cabbage whitefly (Aleyrodes proletella). © A. M. Varela, icipe More Information on Whiteflies
What to do: Natural enemies such as ladybird beetles, predatory mites and lacewings can play an important role in reducing whiteflies. For more information on natural enemies click here. The application of high doses of nitrogen fertiliser favours development of the pest. Use mineral oils and neem. For more information on neem click here. Spray with soapy water solutions.

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Information on Diseases

The most important diseases are blackrot, blackleg, black spot and Turnip Mosaic Virus.

Black rot (Xanthomonas campestris pv. campestris) Black rot is caused by the bacterium Xanthomonas campestris pv. campestris, and is one of the most serious cabbage diseases in warm climates. The black rot bacterium can over-season on infected cabbage seeds, in weeds from the family Cruciferae (including: black mustard, field mustard, wild turnip, wild radish, shepherd's purse, and pepperweed); or in infected plant material in the soil.	Bacterial black rot Black rot on cabbage. Characteristic yellowish V-shaped areas at the leaf margin, sites of infection by black rot, Xanthomonas campestris pv. campestris. © A. M. Varela, icipe Bacterial … Bacterial … Bacterial … More Information on Black rot
What to do: Disease-free transplants should be used or seeds must be treated with hot water treatment as described below. Hot water treatment of own seed to prevent seed-borne diseases such as black rot, black leg, black spot and ring spot is recommended where the disease has appeared before. However, the specified temperature and time interval should be strictly followed in order to maintain seed viability. Use a good thermometer or better ask for assistance from qualified personnel from your local agriculture office. Recommended temperature and time for heat treatment for cabbage: 50°C: for 30 minutes, for broccoli, cauliflower, kale, kohlrabi, turnip:50°C: for 30 minutes. For more details on hot water treatment click here. Establish crops in black rot-free soils that have not grown crops from the family Cruciferae for at least 3 years. Growing cabbage on raised beds with mulching helps eliminate conditions that induce black rot. When possible, remove, burn, or deep plough all crop debris immediately after harvest to reduce the ability of the bacterium to survive in the soil where there is no crop.

White rust (Albugo candida) It affects every known cruciferous crop. However, this disease is generally less common on cabbage, Brussels sprouts, broccoli and cauliflower than on radish, horseradish, mustard and turnip. Leaves have chlorotic or necrotic spots on their upper surface. Pustules form on the lower side of the leaves, small stems and floral parts.	White rust White rust on kales. Note pustules on the lower side of the leaf © A. M. Varela, icipe
What to do: Clean up crop refuse and destroy cruciferous weeds. Crop rotation of at least 3 years can help reduce the disease.

Alternaria leaf spot (Alternaria brassicae) Alternaria leaf spot or black spot is caused by the fungus Alternaria brassicae. The disease can severely damage cabbage if uncontrolled. The initial symptoms are small, circular, dark spots on older leaf surfaces. As the spots enlarge, concentric rings develop within lesions surrounded by a yellow halo. The tan-coloured centres of lesions may eventually fall out, producing a hole, or under wet conditions, may become covered with masses of black spores. In storage, spots enlarge and soft-rot bacteria may enter lesions. The pathogen can over-season on crop debris. Weeds from the family Cruciferae may also harbour the fungus. Spores of Alternaria can be spread by wind and water. The disease is most damaging under wet, warm (20-30.5°C) conditions.	Alternaria leaf spot/Black spot Cabbage black spot - The spots darken with age, and the centers may become thin and papery or drop out, to produce a shot-hole effect. © Gerlach W. Courtesy of EcoPort, (www.ecoport.org) Alternaria… Alternaria…
What to do: Cabbage should never be grown in fields where other Brassica crops have been grown in the past 3 years. Always remove infected plant debris or destroy it after the season. Use disease-free transplants. Crop rotation will reduce the severity of black spot disease. Hot water treatment of own seed to prevent seed. For more details on hot water treatment click here.

Clubroot (Plasmodiophora brassicae) Clubroot caused by the slime mould fungus Plasmodiophora brassicae is particularly serious in Malawi. Its distinctive symptom is an abnormal enlargement of roots or even the underground stem. Its development is favoured by wet, cool, acidic soils.	Clubroot Clubroot on cabbageNote warty growth in the root system © A.A.Seif, icipe
What to do: Practise crop rotation. Irrigate properly. Adjust pH to 7.2 with hydrated lime

Bacterial soft rot (Erwinia carotovora var. carotovora) Bacterial soft rot is caused by Erwinia carotovora var. carotovora. It is quite common on Chinese cabbage in the field. On cabbage, turnip and rutabaga the disease may be found in the field, but is most severe during storage. On cabbage, an initial infection occurs on the outer petiole (leafstalk) which is in contact with the soil, and then progresses to its head. An infected head is watery and often has a complete head rot. The affected area becomes soft and mushy and generally turns dark in colour. Soft rot infection on crucifers almost always emits a foul odour. Eventually the leaves, sterns and roots are entirely decayed by the bacteria. The bacterium is spread in the field by water splashes or contact with tools such as hoes or knives. If contaminated knives are used to harvest cabbages, the stored crop may also rot quickly.	Bacterial soft rot Bacterial soft rot. Note slimy rot (whitish) of the centre of the cabbage head © A. M. Varela, icipe
What to do: Plant on ridges or raised beds to prevent waterlogging around the plants. Prevent other diseases (e.g. black rot; damping-off) or damage that may provide opportunities for soft rot to develop. Avoid harvesting when conditions are warm and moist. These conditions favour the development of soft rot. Harvest healthy cabbage heads first and store in a cool, dry, airy place. Wash hands and harvesting knives. Remove and destroy diseased crop or left over stems in the field after the crop has been harvested. Avoid growing brassica crops in the same field for a period of at least three seasons.

Cercospora leafspots (Cercospora brassicicola) Cercospora leaf spots is caused by the fungus Cercospora brassicicola. Leafspots vary in colour from pale green to white and generally are bordered by brown tissue. They may be circular or appear angular. Severely affected plants may become defoliated. This disease is not economically important in the East African region.	Cercospora leaf spot Cercospora leaf spot on soybean © Clemson University, USDA (EcoPort, www.ecoport.org)
What to do: Use certified disease-free seed and, in case of using own seed, hot water treat the seed. For more information on hot water treatment click here Practise proper weed management, particularly, cruciferous weeds such as mustard. Remove crop residues from the field after harvest.

Cauliflower Mosaic Virus (CaMV) It shows systemic symptoms such as a clearing along the leaf veins (vein clearing). This often is seen first at the base of a leaf. Later symptoms appear as dark green areas along veins (vein banding) and necrotic spotting of the leaf. Chinese cabbage is particularly susceptible to CaMV. In addition to vein clearing a striking mosaic may develop with light and dark green areas seen on the leaves. Plants can be stunted. The main source of CaMV are plants of an infected brassica crop or cruciferous weeds on which a vector has over-seasoned. The virus is transmitted by many species of aphids, such as the cabbage aphid.	Cauliflower Mosaic Virus Cauliflower mosaic virus on kales © A. M. Varela, icipe
What to do: Adequate weed control and sanitation should be practised. Plough-down previous crops rapidly. Transplant beds should be isolated from commercial crop fields and overwintering cruciferous weed hosts.

Damping-off diseases (Pythium spp., Rhizoctonia solani, Fusarium spp.) In crucifers, several fungi (e.g. Pythium spp., Rhizoctonia solani, Fusarium spp.) can cause damping-off diseases. Characteristic is wirestem of seedlings caused by Rhizoctonia solani in the seedbed, bottom rot and head rot in the field, and storage and root rot of horseradish, radish, rutabaga and turnip. Damping-off diseases are favoured by cool, wet soil conditions.	Damping-off disease Damping-off (Rhizoctonia solani) on brassica. © McKenzie, LandCare Ltd., Courtesy of EcoPort Damping-of… Damping-of… More Information on Damping-off diseases
What to do: Use certified disease-free seeds. If using own seed, treat seeds with hot-water. For more information on hot-water seed treatment click here Practise proper irrigation, avoid planting in wet, cold soils Plant on raised beds to reduce moisture content in the root zone and provide the appropriate drainage in the field to prevent waterlogged conditions Practise crop rotation: seedbeds and production fields should not have had crucifers for at least 3 years. All seedlings with wirestem symptoms should be discarded. During cultivation, take care to avoid throwing soil into plant heads.

Turnip mosaic virus (TuMV) The first symptoms to develop when Brassica seedlings are inoculated with TuMV are chlorotic spots on inoculated leaves, mottling followed by systemic vein clearing, mosaic and/or necrosis, leaf distortion and often stunting.	Turnip Mosaic Virus Turnip Mosaic Virus symptoms on cabbage leaves © Image supplied by Warwick HRI, University of Warwick. More Information on Turnip Mosaic Virus (TuMV)
What to do: Remove TuMV-infected plant debris and eradicate infected plants around fields as this can help to reduce virus inoculum and hence spread.

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Other diseases

Treat own seed with hot water
For more details on hot water treatment click here.

Ring spots on cabbage

Downy mildew on cabbage. Symptoms on the lower leaf surface

Cottony rot (Sclerotinia sclerotiorum) on a kale plant

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Information Source Links

AVRDC Training Center: Cabbage www.avrdc.org
CAB International (2005). Crop Protection Compendium, 2005 edition. Wallingford, UK www.cabi.org
Dobson, H., Cooper, J., Manyangarirwa, W., Karuma, J., Chiimba, W. (2002). Integrated Vegetable Pest Management. Natural Resources Institute, University of Greenwich, UK. ISBN: 0-85954-536-9
East African Seed Co. Ltd. Africa's Best Grower^s Guide www.easeed.com
Nega, E., Ulrich, R. Werner, S. und Jahn, M. (2003). Hot water treatment of vegetable seed - an alternative seed treatment method to control seed borne pathogens in organic farming. Journal of Plant Diseases and Protection 110(3):. 220-234. www.orgprints.org
Nutrition Data www.nutritiondata.com.
OISAT: Organisation for Non-Chemical Pest Management in the Tropics www.oisat.org
Varela, A.M., Seif, A. A., Löhr, B. (2003). A Guide to IPM in Brassicas Production in Eastern and Southern Africa. ICIPE Science Press, Nairobi. ISBN: 92 9064 148 7

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Contact Information

Amiran Kenya Ltd. seeds@amirankenya.com
Corner Shop, Nairobi. cls@mitsuminet.com
Dipchem East Africa Ltd. technical@dipchemafrica.com +254722653995
East African Seed Company. www.easeed.com
East African Seed Company. www.easeed.com
Food Network East Africa Ltd. info@organic.co.ke +2540721 100 001
Green Dreams. admin@organic.co.ke +254721 100 001
HCDA. md@hcda.or.ke www.hcda.or.ke +2542088469
Kalimoni Greens. kalimonigreens@gmail,com +254722 509 829
Karen Provision Stores, Nairobi. karenstoresltd@yahoo.com +25420885552
Muthaiga Green Grocers, Nairobi
Nakumatt Supermarket info@nakumatt.net 020551809
National Horticultural Research Centre, KARI, Thika. karithika@gmail.com. +2546721281
Seminis East Africa seminisea@seminis.com + 254202060922
Simlaw Seeds Co. Ltd. simlaw@kenyaweb.com
Uchumi Supermarket info@uchumi.com +25420550368
Zuchinni Green Grocers, Nairobi +254204448240

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