Cucumber farming in Kenya in a nutshell 2022

Cucumber (Cucumis sativus) is a warm season crop that belongs to the family Cucurbitaceae, which is grown for its immature fruits. Cucumbers are great in salads, soups and dips. They could also be used to make pickles. They have very high water content and are very low in calories. If picked while young, cucumbers can add a nice taste to different foods.
Vegetable Cucumber

Cucumber (Cucumis sativus) is a warm season crop that belongs to the family Cucurbitaceae, which is grown for its immature fruits. Cucumbers are great in salads, soups and dips. They could also be used to make pickles. They have very high water content and are very low in calories. If picked while young, cucumbers can add a nice taste to different foods. Cucumbers are a good source of vitamin C.

Ecological Requirements

Cucumber can be grown indoors (e.g., in a greenhouse) or in the open field. The crop does well in loamy, well drained soils, rich in nutrients and with an optimum pH range of 6.5 – 7.5. The optimum temperature for growth is between 18 – 30 °C and they can do well at attitudes of up to 1700 m ASL.

An optimum rainfall of 800 mm is required. However, irrigation is important in order to ensure consistent moisture availability. Cucumbers should be planted at a place where they can get access to at least 6 – 8 hours of direct sunlight. Cucumbers require water regularly. High humidity encourages downy mildew and other diseases.

Field Operations

Planting

Cucumber is propagated by seeds which are usually planted directly in the field. It is also possible to first raise them in a seedbed and transplant into the main field, but this can cause disturbances to their root systems.

2 – 3 seeds are planted in hills or rows, about 2 cm deep and spaced 90 cm by 100 cm.

After seed sowing, the planting holes should be drenched with a mixture of PYRAMID 700WP 5 g/l + LOYALTY 700WDG 10 g/20l + OPTIMIZER 1ml/l. This keeps the field free from soil diseases and pests as well as breaking seed dormancy and promoting uniform germination.

Cultural practices

Weeding

It is very essential to keep the fields free from weeds. This is because weeds compete for growth factors like nutrients, space, water, sunlight as well harbouring pathogens.

Catapult 480SL at 250 ml/20l is a recommended non-selective herbicide when doing land preparation, just before planting

Support or staking

This is necessary for some varieties like greenhouse varieties, and the tip of the main stem can be nipped off to encourage branching.

Irrigation

It should be done frequently to maintain a steady soil moisture level during the growth period. Drip Irrigation is preferred as it ensures that the foliage is dry and prevents spread of diseases.

Mulching

Mulching has several benefits to the cucumber crop, e.g. conservation of moisture, suppression of weed growth, nutrient supply, improvement of soil structure and water infiltration, checking of soil erosion and top soil temperature as well as reduction of pests’ incidence.

Pests & Disease Management

Pests

Cutworms

These are brown biting and chewing pests mostly found in the soil near the plant root zone. They cut down young and tender stems, causing significant crop losses.

Drench soil with PROFILE 440EC at 3 ml/l

Treat seeds with SHIELD 600SF at 3 ml/kg of seeds

Aphids

These are green or blackish soft-bodied insect pests which feed by piercing and sucking sap on tender shoots, especially on the lower leaf surface. The attacked shoots become stunted and the leaves are curled and twisted.

As they feed, aphids excrete honeydew leading to growth of sooty mould, and may attract fruit flies.

They also transmit virus diseases like cucumber mosaic virus when moving from plant to plant and reproduce very fast and thus, if not controlled, they cause significant damages.

Spray PENTAGON 50EC at 0.5 ml/l

Fruit Flies

These pierce the cucumber fruits then lay eggs in the cucumber fruits. Their maggots feed from inside the fruit causing sunken, discoloured patches with open cracks that serve as entry points for fungi and bacteria, causing cucumber fruit rot.

Spray PROFILE 440EC 1.5 ml/l

Whiteflies

These are white-flying insect pests which suck cucumber plant sap and excrete honeydew that encourages moulds to grow, which may affect plant growth and vigor. Affected cucumber plant loses its vitality due to sap sucking resulting in yellowing, downward curling and an eventual drying of leaves.

The tobacco whitefly is a major pest that vectors various virus diseases which cause considerable damage to cucumber.

Spray PROFILE 440EC 1.5 ml/l

Epilachna beetles

The adults and larvae feed on leaves leaving a fine net of veins, and the damaged leaves shrivel and dry up. Young plants can be entirely destroyed while the older ones can tolerate considerable leaf damage.

This beetle is a vector of squash mosaic virus which affects performance of cucumber.

Spray KINGCODE ELITE 50EC 0.5 ml/l

Red spider mites

These feed by piercing and sucking while damaging the crop. Attacked leaves have a stippled appearance which turn yellowish to whitish and dry up.

Spider mites can be a problem in dry and hot conditions, and cucumber plants under water/drought stress are more likely to suffer their damage. They form webs on the undersides of the leaves in severe cases.

Spray ALONZE 50EC 3 ml/20l

Leaf miners

The larvae mine under the leaf surface, resulting into white mines which are irregular in shape and increase in width as the larvae mature.  This reduces photosynthetic area eventually leading to leaf wilting.

Spray ALONZE 50EC 3 ml/20l

Thrips

Both the adults and nymphs are destructive.

They feed on the leaves and most preferably flowers by sucking the sap thus causing damages which may lead to cucumber flower damage/abortion.

Spray PROFILE 440EC 1.5 ml/l

Root-knot nematodes

These are microscopic parasites found in the soil, and infestation by these nematodes leads to wilting of plant.

When the infested plants are pulled from the soil, the roots can be seen to be distorted, swollen and bearing knots or galls. These roots eventually rot causing an eventual death of the plant.

Drench the planting holes with ALONZE 50EC 6 ml/20l

Diseases

Damping off

This is a soil borne disease that causes failure of emergence of seedlings and rotting of the emerged cucumber seedlings. The roots of these infected seedlings exhibit a white cottony growth.

Drench soil with GEARLOCK TURBO 250WP 2.5 g/l

Downy mildew

Small, pale-yellow spots appear on the upper leaf surface while purplish, grey whitish growth appears on the underside of the yellowish spots in humid conditions. Affected leaves curl, shrivel and eventually die

Infected plants get stunted and die while the produced cucumber fruits may be of low quality.

Spray GEALOCK TURBO 250WP 25 g/20l

Anthracnose

Disease symptoms are mostly noticeable on fruits as circular black or brown sunken lesions. When wet, the centres of these lesions become purplish coloured due to a mass of fungal spores. However, water soaked lesions are also seen on the leaves and stems. On the stem they can girdle the stem causing wilting of the vines.

Spray ABSOLUTE 375SC 0.5 ml/l

Angular leaf spot

Infection causes development of spots on leaves which are angular in shape and variable in size due to the size of the leaf veins. Initially these spots are water soaked. Severe cases of infections can cause defoliation.

Spray RANSOM 600WP at 15g/20l

Powdery mildew

Symptoms first develop as whitish talcum like powdery growth on upper leaf surface. As infection progresses, the stems also get infected. Severely infected parts turn yellowish and eventually wilt.

Spray RANSOM 600WP 15g/20l

Fusarium wilt

Initially, symptoms appear as chlorosis of the leaves, and as infection progresses, leaves begin wilting from bottom to top. The brown vascular discoloration inside infected stem or root leads to the eventual death of plants.

Drench soil with GREENCOP 500WP 5 g/l

Cucumber mosaic

This is a viral disease, and the virus is mechanically transmitted and also spread by several species of aphids in non- persistent mode.

Attacked cucumber leaves show symptoms of reduced size and patches of dark-green tissue alternating with yellow-green. Generally, the plant becomes stunted and fruits develop water soaked lesions with central solid spots.

Control aphids (vectors) with KINGCODE ELITE 50EC  at 0.5 ml/l

Nutrition and Nutrition Deficiencies

For an optimal productivity of cucumber, sufficient amounts of nutrient should be supplied. Besides the application of foliar feeds is highly essential besides the basal fertilizers and manure.

For instance;

At planting, soil should be mixed with manure and DAP and top dressing can be done after 3 – 4 weeks using CAN.

To improve root development and stimulate cucumber plant growth, GOLDCHANCE SUPER START at 2.5 g/l or LAVENDER SUPER START at 1 ml/l should be sprayed in order to provide adequate Phosphorous essential for root development, amongst other nutrient elements.

For a robust vegetative growth, GOLDCHANCE SUPER GROWTH at 2.5 g/l or LAVENDER at 1 ml/l are sprayed to supply enough Nitrogen which is highly required in development of foliage, important for photosynthesis, besides other elements.

During flowering and fruiting stages of the cucumber plant, spray GOLDCHANCE SUPER FLOWERS & FRUITS at 2.5 g/l, VITABOR GOLD at 1 ml/l, and DIMIPHITE 600 at 1.5 ml/l. These 3 provide nutrient elements needed to induce flowering and fruiting, prevent flower abortion as well as ensure production of good quality fruits.

Deficiencies

Phosphorous deficiency

Deficient plants become stunted, internodes shorten, leaves turn purplish and there’s production of poor quality flowers which bear low quality fruits.

Spray DIMIPHITE 600 at 1.5 ml/l

Nitrogen deficiency

The growth rate of deficient plants is highly reduced and leaves turn yellow, starting with the older ones.

Spray Lavender Super Growth at 1 ml/l

Potassium deficiency

Young leaves become small, dull and cupped while the older ones develop marginal chlorosis. In severe cases, leaves dry.

Spray DIMIPHITE 600 at 1.5 ml/l

Boron deficiency

The growing points of affected plants die and leaves become chlorotic, then necrotic. Fruit quality is greatly reduced.

Spray VITABOR GOLD at 1ml/l

Calcium deficiency

The leaves of calcium deficient plants stop expanding and fold downwards. Blossom end rot of the cucumber may occur in severe cases of deficiency.

Spray FERRARI GOLD at 3 ml/l

NOTE

  • Whenever doing foliar sprays, always mix the product(s) with INTEGRA at 3 ml/20l. This is a sticker, spreader and penetrant which helps in improving the products’ efficacy, giving more effective results.
  • JAMBO CLEAN at 5 ml/l is used to clean sooty mold which results after infestation with sap-sucking pests.
  • Alternation of various chemicals (especially fungicides and insecticides) throughout a crop’s season help in preventing resistance build-up by the pest, which could happen if only a single chemical was used.
  • All basal fertilizers and manures should be mixed with HUMIPOWER, which adds organic matter into the soil, improves nutrient uptake, stimulates beneficial microbial activities, promotes electrochemical balance and stimulates plant’s development among other benefits.

Harvesting & Post Harvest Handling

Cucumbers are ready for harvesting about 50 – 60 days after planting, depending on the cultivar and ecological conditions, especially temperature.

Harvesting is done by picking the cucumber at a range of developmental stages.

Fruits are harvested at a slightly immature stage, near full size but before seeds fully enlarge and harden. Firmness and external glossiness are also indicators of a pre-maturity condition. At proper harvest maturity, a jellylike material begins to form in the seed cavity.

Cucumber quality is majorly based on uniform shape, firmness and a dark green skin color. The size, freedom from growth or handling defects and decay, and an absence of yellowing are important quality factors.

Harvested cucumber can be stored for less than two weeks because their visual and sensory qualities deteriorate rapidly. Shriveling, yellowing, and decay are likely to increase following storage beyond this period of time.

Short term cucumber storage or transit temperatures below 7°C are commonly used but result in chilling injury after 2 – 3 days.

Cucumbers can be treated with approved waxes or oils to reduce water loss, reduce abrasion injury and enhance appearance.

Cucumber Yellowing during the postharvest period is a very common defect. Harvesting fruit at an advanced stage of development, exposure to ethylene, or storage at too high temperature all cause yellowing.

Last updated on Monday, March 6, 2023 at 12:18 pm

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