Growing Capsicum

Capsicums (also known as bell peppers or pilipili hoho in Swahili). The vegetable belongs to the solanaceae family It does very well  in hot areas such as Eastern Province, Coastal region, temperate central areas, etc. Capsicum performs well under irrigated conditions. The optimum temperatures for growth are 15ºC-25 ºC. The low night temperatures in July/ August in Kenya are favourable for production of this vegetable. Seedlings take 21 days to germinate, 45 days in the nursery bed and 90 days to mature. At a spacing of 75cm by 45cm one acre can accommodate 10,000 plants, each yielding about 10 heads to give a total harvest of 100,000 heads.

The vegetable plant tolerates a wide range of climate from warm temperate to tropical, including irrigated dry hot areas. Capsicums are sensitive to frost and optimum temperature for  growth and fruit set are 15-25ºC. The vegetables grows well in altitudes up to 2,000M. Capsicums  can be grown on a wide range of well drained loamy or heavy cracking clay soils with optimum ph of 6.0-6.5.

FIELD OPERATIONS

Planting

Propagation of capsicum is by seeds, which are first raised in a nursery before transplanting into the main field.

Land preparation

The land should be thoroughly prepared by ploughing and harrowing to a clean and fine tilth. To get rid of both broadleaf and grass weeds, spray them with a systemic non-selective weedkiller.

Raising seedlings

Procedure

  • Prepare the nursery bed, about 1 metre wide against the required length.
  • Sow seeds at a depth of about 2cm and cover them lightly with soil.
  • Cover nursery bed with a thin layer of mulch.
  • Water the nursery bed.

Tips!

  • Seeds germinate within 2 to 3 weeks depending on the variety and the ecological conditions.
  • The beds should be shaded to protect the seedlings from direct sunlight and strong wind.
  • Proper nutrition promotes production of strong and healthy seedlings hence a healthy crop when transplanted.

Transplanting

Seedlings are ready for transplanting after attaining 4-5 leaves, which is approximately 6 to 7 weeks after sowing. To harden the young plants, the rate of irrigation should be reduced, a week before transplanting, and the shading withdrawn. Before lifting the seedlings, the nursery bed should be irrigated.

Procedure

  • Make raised or sunken beds on the prepared land.
  • Mix soil with manure and fertilizer. For efficient and improved nutrient uptake and stimulation of root development, among other benefits, add manure.
  • Irrigate the beds to allow for easy planting.
  • Plant the seedlings in the beds at a spacing of 75x45cm.

Tips!

  • Transplanting is best when done early in the morning or in the evenings.
  • Transplant only the healthy and strong seedlings.

Weeding

Capsicum does not compete well with weeds and therefore the field should be kept weed-free. These weeds cause significant losses because they compete for growth factors like nutrients and water and harbour pathogens which could attack the crop.

When the crop begins flowering, weeding should be minimized in order to prevent disturbances. However, if need be, the weeds can be uprooted.

Tip!

  • Proper weed control before planting the crop significantly reduces weed development throughout the season.
  • Shallow cultivation should be done in order to avoid root injury.

Irrigation

Capsicum requires adequate water supply for optimal production. Inadequate water supply causes stress, wilting, flowers abortion and development of physiological disorders like blossom end rot.

Crop rotation

This practice helps in pests and disease management by breaking the development cycles of the pathogens. Rotation should be done with non-solanaceous crops like tomato.

Tips!

  • Soil testing is important because it helps in determining the soil fertility status.
  • Manure should be applied especially for soils with little or no organic matter.

Yield

If proper maintenance of the crop is ensured, 5 to 8 tonnes per acre can be realized. However, this depends on the variety grown.

HARVESTING

Harvesting can begin 2.5 to 3 months after planting, depending on the ecological conditions and the variety grown, and this can continue for 4 to 6 times if good management is ensured.

Depending on the purpose for which the crop is grown and the availability of market, harvesting can be done at green, partially green and red or yellow colour stages.

The harvested fruits should be placed under shade for sorting, grading and packaging.

POST-HARVESTING HANDLING

Sorting- this involves removing the bruised/damaged, malformed or diseased fruits.

Grading the fruits are graded according to shape, size and colour.

Packaging the fruits are packaged in corrugate cartons or in crated.

Storage and transportation– these should be done in cool conditions at relative humidity of 95-98%.

Tips!

  • A mature green fruit is usually firm, thick-walled and bright green.
  • The demand for capsicum in the market is relatively higher than the supply. Some of the market opportunities for the produce include food processors, supermarkets, and wholesale markets, among others.

MAJOR PESTS &DISEASES

Pests

Cutworms– these are soft bodied, smooth caterpillars, brown to black in colour, which cut seedlings or young plants near the soil level mainly during morning and evening hours. When disturbed, they curl up tightly. Heavy infestations cause significant crop loss.

Thrips these are small, slender insects with fringed wings and unique asymmetrical mouth parts which feed on leaves, flowers and tender fruits by sucking the sap. Infestation causes distortion of leaves, stunted growth, sunken tissues on leaf underside, silvery appearance on flowers and scarring of fruits.

Red spider mites-these are tiny sucking pests which are usually found on the underside of leaves and spin protective silk webs. Infested leaves turn yellow and curl upwards and heavy infestation causes death of the leaf. Crops under water or drought stress are more likely to suffer serious damages by the pest.

Aphids– these are usually light green and soft bodied, and cluster on the undersides of the leaf or on stems. They feed by sucking plant’s sap with severe infestations causing wilting, stunting and leaf curling and distortion. They also excrete a sticky sugary substance called honeydew, which encourages the growth of sooty mold.

WhitefliesThese are white and winged insects which suck plant sap and excrete honeydew where molds grow, affecting plant’s growth and vigour. The affected plant loses its vitality due to sap sucking resulting yellowing, downward curling and finally drying of leaves. They are also vectors of Tomato Yellow Leaf Curl virus.

Root knot nematodes– these are microscopic parasites found in the soil and whose infestation leads to formation of galls/swellings on the roots, which reduces plant vigour thus causing stunting of the plants and eventual death.

Diseases

Damping-off this is a soilborne disease caused by Pythium spp, Rhizoctonia spp, and Fusarium spp which frequently occurs in the nursery.  The diseased seeds do not germinate while the emerged seedlings rot and eventually die. White cottony growth is seen on the roots of the infected seedlings.

Anthracnose it is caused by a Colletotrichum spp. Disease symptoms are mostly noticeable on fruits as circular black or brown sunken lesions and when wet the centres of these lesions become purplish coloured due to a mass of fungal spores. Water soaked sunken lesions also develop on the leaves and stems.

Bacterial wilt– this is a soil borne disease caused by the bacterium Ralstonia solanacearum. Infection causes wilting, which starts with the young leaves. However, these leaves seem to recover during the cool weather. The vascular tissues become discoloured turning yellow to brownish, and as infection progresses, they become dark brown to black. When the stem is cut under water, white slimy sticky ooze is seen. The wilted crop eventually dies.

Bacterial cankerthis disease is caused by the bacterium Corynebacterium michiganese. Infection leads to development of scabby canker spots on the fruits. It may also produce local lesions on fruits, stems and leaves, but does not induce systemic infection on the plant.

Bacterial soft rot– this is caused by the bacterium Erwinia carotovora, which causes soft rot of the fruit. On infection, the internal tissue of the fruit softens, turns into a watery mass and produces a foul smell. The disease is favoured by hot and humid weather conditions and the rot can worsen after harvesting, in transit and in the market.

Powdery mildew –this disease is caused by the fungus Leveillula taurica. Symptoms are initially seen as whitish talcum-like powdery growth on upper leaf surface and as infection progresses, the other parts also get infected. Severely infected parts become chlorotic and eventually die.  Stunted growth is evident.

Phytophthora blight– it is caused by the fungus Phytophthora capsici. It affects all plant parts causing foliar blight, fruit rot, and root rot and spreads very fast when humidity and temperature are high and/or the soil is wet. In severe cases, wilting occurs and the crop dies with few days. , and within days, the plant dies.

Fusarium wilt this is a soil borne disease caused by the fungus Fusarium oxysporum. Initially, symptoms appear like vein clearing on the young leaves and dropping of the older lower leaves. As infection progresses, the leaves turn yellow and wilt. The brown vascular tissues are brownish in colour but do not produce a slimy substance when the stem is cut under water, like in the case of bacterial wilt.

PHYSIOLOGICAL DISORDERS

Blossom End Rot – this is deterioration of the blossom end of the fruit which starts with softening, slight shriveling, browning, blackening with increased shriveling, and sometimes secondary decay. It is caused by lack of calcium nutrition and moisture stress. Application of calcium-rich fertilizers and maintenance of moisture consistence are recommended.

Sunscald– this occurs as a result of exposure to excessive direct sunlight on the fruits, especially those that have been growing in a shaded canopy. The fruit develops a whitish or necrotic area on the side of the fruit which is exposed to the sun. Secondary infections by fungi are common. The condition can be managed by keeping the fruits shaded by the crop’s leaves.

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