Tomatoes

Tomatoes Production in Kenya

Smallholder tomato farming in Kenya remains dominated by older men despite efforts by the government NGOs to encourage women and youth into agriculture and to foster equality in land ownership, scientists have found.

In Kenya, seven out of ten tomato growers are male according to a study conducted by a group of Nairobi-based scientists and published in Scientific African in March. Of these male farmers, 73% are between the ages of 36 and 60.

It suggests that women and youth benefit less than they might from Kenya’s booming tomato growing industry, the researchers say in their paper. “The findings of this study underscore the need to increase women and youth participation in tomato production.

TOMATOES

1. Planting

Soil Requirement

• Well drained, light loam with high content of organic matter and PH of 5 to 2.5.

Seed rate

• 1 to 1.5 kg/ha for direct sowing, 150 to 200 gm/ha for nursery sowing.

2. Nursery Establishment

• Make fine tilth seedbed
• Drill seeds thinly in rows 20cm apart and 1cm deep.
• Keep soil moist but not water logged.
• After germination thin to 7cm apart in a row to ensure strong seedling.

3. Field Establishment

• Space holes 1m by 0.5m to give a population of 20,000 plants/ha.
• Apply manure at the rate of 2 handfuls per hole and mix thoroughly.
• Apply DSP/DAP at 200kg/ha (1 teaspoon per holes) during planting.
• Transplanting is done a month after germination
• Top dress with CAN at the rate of 100kg/ha when plants are 25cm high.
• Top dress again with CAN at 200kg/ha four weeks later.
• Maintain mulch especially for determinate varieties (It keeps the fruits clean, conserves moisture and keeps soil temperatures low).
• Weed regularly (Weeds compete for nutrients and also act as hosts of diseases and pests)

4. Staking and Pruning

Staking

• For tall growing indeterminate varieties a 3m stake should be put firmly in the ground for each tomato plant and the stem loosely tied as the plant grows.

Pruning

• Necessary for indeterminate varieties.
• Allow one or two main stems to grow, pinch off the lateral shoots weekly.
• When 6 to 8 trusses are formed the growing top is pinched off.
• Leaves close to the ground should be removed to prevent entry of blight.

Irrigation

• Irrigate 2 – 3 times a week. during dry weather

5. Physiological Disorders
6. Nutrients Disorders

• Potassium deficiency results to fruits with poor taste and hollow cavity.
• Phosphorus deficiency will result in stunted growth, delayed maturity and reduced yields.
• Nitrogen excess will result in small fruits and blossom end rot.
• Calcium deficiency will result in blossom end rot.

2. Blossom End-rot

• Early signs of the disorder are a water soaked spot near the blossom end of the fruit.
• This turns brown and enlarges to cover almost half of the fruit.
• The causes are normally;-
  • Too fast growth during the early stages followed by sudden drought especially when the fruits are small.
  • Excessive nitrogen and infrequent watering.
  • Calcium deficiency especially in young fruits.
  • Low application of nitrogen to calcium deficiency soils

• Control: –
  • Application of CAN
  • Apply calcium chloride foliar feed at 15kg/1000 liters (Higher concentration will damage leaves).
  • Lime calcium deficient soils.

6. Diseases
7. Late Blight
8. Symptoms

• Occurs under cool and high humidity conditions especially wet season.
• It is characterized by rapid drying of leaves and brownish dry rot of fruits often destroying the whole crop.

1. Control

Spray with Ridomil or Antracol shortly after emergence at intervals of every 4 days in wet weather and fortnightly in dry weather.

2. Early Blight
3. Symptoms

• It occurs during hot weather.  It causes stem cankers on seedlings and small irregular dark brown spots on the leaves.  As they enlarge they show a concentric pattern.  The result is partial defoliation of the crop.
• It causes premature fruit drop and low quality fruits.
• It is soil borne and the fungus usually survives on plant debris.

1. Control

• Field sanitation.
• Crop rotation.
• Foliar sprays as for late blight.

3. Septoria leaf spot
4. Symptoms

• Disease occurs at all stages of the plant.
• It attacks the solanaceae family and survives on plant debris.
• Its development is favoured by wet weather.
• It is characterized by the presence of tiny brown black angular leaf spots on leaves.  The sports can cause defoliation which then exposes fruits to sun scald.  In severe attacks, lesions appear on stems and fruit stalks.

1. Control

• Spray with Benlate.
• Keep field free from weeds.
• Remove and burn infected debris.
• Crop rotation.

4. Bacterial Canker
5. Symptoms

• It is seed borne.  It can reduce yield to 90% especially in indeterminate varieties.  The bacteria can survive in cracks on the sticks used for staking.
• Symptoms include wilting and curling of the leaflets of the lower leaves.  Dried, whole leaves curls upwards, turn brown wither but remain attached to the stem.  The stem may split open and the pith is often discoloured.  Young fruits show discolouration of vascular system, they show deformation and stunting on mature fruits birds eye spots are visible.  Excess nitrogen favours its development.

1. Control

• No chemical control has been found effective.
• Planting healthy seedlings.
• Crop rotation.
• Field sanitation.
• Disinfect pruning knife after pruning.
• Avoid over fertilizing the crop with nitrogen.

5. Fusarium Wilt
6. Symptoms

• Development is favoured by high temperature, low humidity and nutrient deficiency.  It is soil borne and survives in plant debris.
• The symptoms include yellowing and wilting of the lower leaves, slightly dropping at high temperatures.  The vascular vessels appear brown.  In cool conditions it affects the root area only causing tomato root rot wilt.  Browning of the vascular vessels is restricted to the stem near the soil level but roots show a severe browning and decay.

1. Control

• Use of resistant varieties.
• Liming.
• Crop rotation.

6. Bacteria Spot
7. Symptoms

The disease is seed born hence infection can start in the nursery.  It is spread by rain splash and sprinkler irrigation.  The disease attacks foliage but is most conspicuous on fruits.  Irregular dark green spots appear on the foliage which eventually dries.  It may cause blossoms to drop.  On fruit the initial spot is very small and water soaked and eventually enlarges.

1. Control

Foliar spray using copper based fungicides.

7. Pests
8. Root Knot Nematodes.
9. Symptoms

These include swellings on the roots causing stunting of the plants and eventual wilting.

1. Control.

• Crop rotation.
• Plant nematode free seedlings.
• Keep field free of weeds.

2. American Bollworms
3. Symptoms

The caterpillar bore into fruit and feed on the inner part of the fruit releasing plenty of excreta which is noticeable on damaged fruits.  The entry point of the caterpillar acts as entry point for bacteria and fungi.  It attacks sweet pepper, tobacco, sorghum.

1. Control.

Spray with Dalathion, Lebaycid at 2 weeks before fruit set and then karate, Decis during and after fruit set.

3. Tobacco White Fly
4. Symptoms

Small white moth-like flies fly from foliage when plants are disturbed.  The nymph sucks sap from underside of the leaves.  They transmit virus.  They cause leaf distortion and stunting if attack is early.

1. Control

• Same as American bollworm above but spray thoroughly on the underside.
• Other insecticides used include; – Dimethoate, Sumithion or Brigade.

4. Red Spider Mites
5. Symptoms

These are minute spider like animals found on the underside of the leaves.  They cause speckling and tarnishing of the leaves which turn yellowish and whitish.  Severe infestation causes stunted growth, leaves dry up and falls off.  The problem is acute in dry areas or irrigated crops.

1. Control

Brigade at 24ml/20 liter, Dimethoate at 15ml/20 liter, Metasystox at 15ml/20 liter and Kelthane (or as label instructions).

5. Aphids
6. Symptoms

These are plant lice that suck sap from leaves causing leaf distortion especially during dry spells. Aphids prefer young leaves, stems or flowers.  Their secretion causes sooty mould.  They transmit viral diseases.

1. Control.

Spray with dimethoate 40% c.c. at 15ml/20 liter water, or Fenitrothion 50% E.C at 15ml/20 litre of water.

8. Harvesting

Harvest tomatoes by picking the fruits that have changed or are starting to change colour

9. Variety Characteristics

Variety	Fruit wt (gm)	Days to Maturity	Yield Tons/Ha	Disease Resistance
Money maker	75	67	32-50	Susceptible
Marglobe	188	70	38	– do –
Beauty	80	70	20	– do –
Roma UF	53	120	83	Resistant to Fasarium wilt
Cal J	68	120	73	Susceptible
M – 82	53	120	57	– do –
Riogronde	74	128	84	– do –
* Rubino	–	110	84	– do –
*Parmamech	–	110	75	Susceptible
*Parma VF	–	110	79	– do –
*Nema 140 L	85	118	39	Resistant to nematodes
*Picardor	–	110	41	Susceptible
*Spectrum	81	110	38	– do –
*G 527	45	120	37	Resistant to Fusarium wilt and nematodes
*Nema 1400	90	117	37	Resistant to nematodes
*Nema 1200	82	109	34	– do –
*Capitan	100	74	67	Resistant to some stains of bacterial wilt.
*Tropic	230	74	58
*Kentom 1	100	65	65	Resistant to nematodes
*Kentom 2	120	70	65	Resistant to nematodes and bacteria wilt.