This tomato is believed to have its origin in the Peru-Ecuador areas from where it spread as a weed
many parts of tropical America and then domesticated in Mexico. It was introduced into Europe early in
the sixteen-century and the United States of America two centuries later. Tomato belongs to the family
Solanaceae and its scientific name is Lycopersicon esculentum. Tomatoes can be considered one of the
most important vegetables. The fruits can be cooked or eaten raw. Additionally, this vegetable is used
extensively in the
canning industry in the production juices, sauces, ketchup and paste
In Guyana, the varieties are described as “Creole” and “English”. Within the Creole there are the smell
rounded cherry types and the large flat types. “English” are those varieties that are imported and include
Heat Master, Heatwave, Capitan, Alafua Winner, TA, TB, and TC etc.
Plants are propagated from seeds that should be sown either in seed boxes or in seedbeds from where
they are transplanted into the field.
As a precaution against seed-borne disease, seeds should be treated with fungicides e.g. Captan, Mancocide
at 2-3 g/kg seed. Seeds can also be treated with 0.8% acetic acid overnight or in hot water (50°C) for 30
Sterilize seed-box or nursery bed with Formaldehyde 1:3 (1 part in 3 parts water), Captan or Phosal 80
Wp at 2g/ liter of water. The use of Rhilolex to treat the soil has also been shown to be effective. Cover
soil with a polyethylene bag for one day. Seeds should not be sown until 5-6 days after.
Moisten soil before sowing seeds. Use a mixture of four parts pen manure or compost, three parts burnt
rice husk and one part black sand. Scatter thinly over the area. Barely cover seeds with soaked jute bag,
which should be kept, damp and removed immediately after germination commences. Germination should
take place 3-4 days after sowing.
Shading is necessary to protect young seedlings from being burnt by the sun or beaten down be rain.
Overhead shades about 30cm above the seedbed should be provided. Saran netting or coconut branches
can be used to provide shade.
As seedlings grow and produce 4-5 leaves, progressively remove shade thus allowing them to be ex-
posed daily to more and more hours of sunshine until they receive the total day’s sunlight. During this
period of hardening the amount of water applied to seedlings should be reduced.
Transplanting: It is advisable that the following guidelines be followed when transplanting:
(i) About 6-9 days before transplanting, harden seedlings by slightly withholding water and exposing
M them to strong sunlight by removing the shading. Thoroughly water plants 12 to 14 hours before trans-
planting to the field;
(ii) The ideal transplant is a seedling with 3 to5 true leaves, disease-free and well grown for variety,
stocky and succulent, and not yet having flower buds or flowers;
(iii) Dig a hole for each plant deep enough to bury it so that the first true leaf is just about the soil surface;
(iv) Leggy plants, which have grow past the ideal size for transplanting, should be buried deeper. Pull off
a few older leaves and, to make planting easier, bend the stem and lay it in sideways;
(v) Press the soil firmly around the root, then top irrigate lightly to settle the soil;
(vi) Furrow irrigate the field as soon as possible;
(vii)Transplanting should be done in the late afternoon to minimize shock under high temperatures; and
(viii) About 7 days after transplanting replant any missing plants.
A soil test should be done to determine the fertilizer requirement. As a guide the following recommenda-
tion should be followed:
30% at transplanting (1.5g/plant)
40% at flowering (2.0g/plant)
30% at Fruit set (1.5g/plant)
All at transplanting (2.2g/plant)
50% at transplanting (1.6g/plant)
50% at flowering (1.6g/plant)
If organic manure is being applied, then synthetic fertilizer rate should be lowered.
Soil and Crop Management
Proper soil and crop management entails the following:
(i) If the land is dry, irrigate before land preparation;.
(ii) Plough with a rotavator (or fork and chip);
(iii)Form the bed 100-cm wide and 20-25 cm high and leave furrow between beds 50cm wide;.
(iv) Dig one row to a depth of 15-25 cm in the middle of bed. The recommended spacing should be 60cm
between the rows and 45cm along the rows (approximately 37,000 plants/ha).;
(v) Place basal fertilizer into the row and cover with soil prior to spraying with pre-emergent herbicide
(vi) Spray lasso into the bed before transplanting;
(vii) Keep the space between hills at 40cm;
(viii) Stake a 150-180 cm bamboo pole beside each plant 3-4 weeks after transplanting:
(ix) Mulch the bed with rice straw or dry grass the during dry season; and
(x) Tie the vine to the bamboo stake and pinch off the sprouted auxiliary bud in order to maintain a single
stem per plant.
It is recommended that weed control be done manually. If herbicides are to be used, the following are
- Spray Lasso with sprayer at rate 9m1/litre of water on the top of bed before transplanting. Lasso is
more effective when the soil is relatively moist; or
- Spray Gramaxone or Amaxone with a nozzle shield at the rate of 6ml/litre of water. Avoid contacting
tomato plant with these chemicals.
It is desirable to have the soil well supplied with water before ripening begins so that subsequent irriga-
tions may be kept to a minimum. However, don't keep the air spaces in the soil filled with water.
INSECT PEST MANAGEMENT
The tomato russet mite, Aculops lycopersici is smaller and more
elongate that spider mites, with the body tapering toward the rear
end. This mite is pale in colour and, like spider mites, has eight legs
-Mites Attack the undersides of lower leaves, causmg them to be-
come silvery and chlorotic and then necrotic;
- As the attack spreads, stems and leaf petioles appear bronzed, and
lower foliage desiccates; and / or
- Plants may be killed in only a few days in hot dry weather.
Fig 1. Mite
Control: The control measures recommended are:
- Chemical control; spray with Hostathion, Abamectin (lOml/5 liter of water) etc.; and or
- Effective weed management.
There are two main species of aphids (Figure 2) that attack tomato. The potato aphid, Macrosiphum
euphorbiae, is a large aphid, which may be either green or pink. The green peach aphid, Myzus persicae
is smaller and light
to dark green in colour. Aphids invade tomato fields as winged adults but produce unwinged offspring
parthenogenetically. There have piercing-sucking mouthparts and disseminate important viral diseases
Symptoms: The Symptoms of Aphids are:
- Sooty mold can be seen growing on heavy honeydew secretions
T from the insects;
- Chlorotic spotting;
- General chlorosis and distortion of leaves; and / or
O - Stunting and wilting of plants.
M Control: The Control Measures recommended for Whiteflies are:
- Chemical control using chemicals such as Fastac, Vydate L,
A - Crop rotation; and or
Fig 2. Aphids on tomato leaf
- Weed control
The sweetpotato whitefly, Bemisia tabaci, (Figure 3) is common in the field and a vector of several
O important viral diseases around the world. Whiteflies life stages occur on the undersides of tomato
leaves. Whitefly adults are always winged and have a white, powdery wax on their wings and bodied.
Symptoms: The Symptoms of Whiteflies are:
- Production of honey dew ( and the growing of sooty mold on it);
- Chlorotic spotting and chlorosis of leaves; and /or
- The spotting of fruit, and the stunting and wilting of plants.
Control: The Control Measures recommended for Whiteflies are:
- Planting of trap crop to attract whitefly away from the economic
- Good weed management ;
- Good soil management; and /or
- Spray with chemicals such as Admire, Basudin, Abamectin (lOml/S
liter of water), extract from neem leaves or seed etc.
Fig 3. Whiteflies
Thrips palmi are small elongate insects, They primarily attack tomato flowers and the adults are usually
yellow or brown and have slender, featherllke wings fringed with long hairs (Figure 4). The eggs are
inserted into succulent plant tissue, including leaves, stems, pistils, or small fruit.
Symptoms: The Symptoms of Thrips are:
- Damaged tissue which initially appears silvery but may turn necrotic or
- Increasing flower drop; and /or
- Discolored fruits
Control: The Control Measures recommended for Thrips are:
- Weed control;
- Crop rotation; and /or
- Chemical control, with chemicals such as Abamectin (lOml/5 liter of wa-
Vydate L, Fastac, Karate etc.
Fig 4. Thrips
These are tiny yellow maggots that tunnel between the leaf surface.
Symptoms: The Symptoms of leafminer are:
- Damage done by their feeding habits, which leave irregular trails on the
leaves (Figure 5);
- Yellowing and drooping of leaves; and /or
- Loss in yield.
Control: The Control Measures recommended for leafminer are:
- Crop rotation;
- Spray with Abamectin, Trigard, Vydate L etc.; and /or
Fig 5. Symptoms of
- Weed control
CUCUMBER MOSAIC VIRUS (CMV)
This disease is widely distributed in the tropics.
Symptoms: The symptoms of CMV are:
- Crinkled leaves;
- Necrosis on the stem and leaves (Figure 6);
- Sun scald on fruits; and/or
- Reduction of number of flower and fruits produced.
Fig 6. Symptoms of CMV
Mosaic virus is transmitted by seeds, by soil through the debris of infected plants and mechanically
from the infected plants by farm practices, namely, transplanting, disbudding etc. Continuous cropping
enhances the disease incidence.
In order to manage the CMV infected plants should be rouged. Alternatively seeds should be treated
with hot water at 50°C for 30 minutes before planting .
SPOTTED WILT (SW)
Tomato spotted wilt virus is common and important in the tropics.
Symptoms: The Symptoms fo SW are:
- Yellowing of leaves;
- Wilt of leaf tips;
- Appearance of brown necrotic lesions on leaves (Figure 7).;
- Necrotic streaks on stem and petioles.; and/or
- Distorted fruits.
Fig 7. Symptoms of
The virus is transmitted by thrips in a persistent manner. The virus is not transmitted through seeds or
Control: The control measures recommended for SW are:
O - Rouge infected plants;
- Use good management practices; and /or
M - Control insect pests.
A Tomato yellow leaf curl virus (TYLCV) belongs to the Geminivirus
Symptoms: The typical symptoms of TYLCV are:
- Dwarfism and curling in newly developed leaves (Figure 8);
O - Curling, twisting and interveinal yellowing in lower leaves:
- Young plants are stunted and apical leaves proliferate; and/or
- A small number of flowering buds are produced.
TYLCV has a narrow host range and tomato is the only crop dam-
Fig 8. Symptoms of TYLCV
aged. Tobacco white fly transmits the virus in a persistent manner.
Control: The control measure of TYLCV include:
- Good crop management practices;
- Rouge infected plants; and/or
- Spray insecticides to control vector (Admire, Abamectin (lOml/S liter of water), Basudin, Regent etc).
BACTERIAL WILT (BW)
The causal agent is Pseudomonas solanacearum
Symptoms: Typical symptoms of BW are:
- Wilt on leaves and shoot apex with no color change; and/or
- Browning on the vascular strands of the basal part of the stem in
the wilted plant (Figure 9). When a section of infected stem with
browning of the vascular stem is placed in water, a milky white bac-
terial exudate oozes out from the cut surface in a few minutes.
Wilting occurs mainly in the wet season and is easily spread by run-
ning water or splashing from raindrops.
Fig 9. Symptoms of
Control: Types of control measures are as follow:
- Provide adequate drainage to remove excess water;
- Pull out and destroy infected plants to reduce spread of disease;
- Apply limestone to achieve a pH of 5.8 - 6.8. This pH level will render conditions unfavorable for
- Spray soil with Phyton 27 (fungicide) at transplanting during the wet season; and /or
- Plant resistant varieties.
BLOSSOM END ROT
Symptoms: The symptoms of blossom end rot are:
Small water-soaked spots at the bottom end of the fruit which en-
large overtime into large blackish -brown sunken water - soaked ar-
eas (Figure 10).
This is caused by a physiological disorder as a result of uneven levels
for water application combined with a lack of calcium in the soil.
Control: The recommended measures of control are as follow:
- Apply limestone one month before planting to achieve a pH of 5.8 - 6.8. Fig 10. Symptoms of
- Maintain watering at a constant level. Too much or too little water at
blossom end rot
irregular intervals can create conditions for blossom end rot; and or
- Spray calcium base liquid fertilizer at flowering
BACTERIAL SOFT ROT (BFR)
The causal agent is Erwina carotovora
Symptoms: The symptoms for Bacterial Soft Rot
- Leaf margins become dehydrated, and leaf blades
wilt with yellowing and drying up (Figure 11);
- In main stem, dark to blackish brown water-soaked lesions are formed;
Fig 11. Symptoms for bacterial
- Discolored parts surround the stem and spread to the pith; and /or
- When stem is pressed with fingers a juice with rotten smell is obtained.
The pathogen enters the host through feeding traces of insects and at sites of mechanical injury due to
or rain. High temperature and high humidity conditions enhance the severity of the disease.
Control: The recommended measures of control are as follows:
- Avoid continuous cropping;
- Good soil drainage; and/or
- Spray copper compound (fungicide) for effective control. e.g. Benlate, Trimiltox, Kocide DF etc.
The causal agent is Pseudomonas corrugata
Symptoms: The symptoms of Pith Necrosis are:
- Pith of stem and petiole show browning and necrosis (Figure 12);
O - Browning of vascular bundles and ooze of bacterial exudate
are observed; and /or
M - Upper leaves show slight yellowing and wilt.
A Bacteria which survive in irrigation water or in soil may enter through
foliage wounds at transplanting or thereafter. Pith necrosis occurs mainly
in plants that become weak when grown under low temperature and high
O Control: The recommended measures of control are as follows:
- Use healthy soil for raising seedlings;
- Remove infected plants as soon as they appear;
- Provide adequate drainage during the rainy season; and /or
Fig 12. Symptoms of
- Spray Phyton 27 at transplanting.
The causal agent is Phytophthora infestants
Symptoms: The symptoms of Late Blight are:
- Lesions on leaves which initially appear as small water soaked irregu-
lar spots with grayish green colour later becoming dark gray (Figure
- On stems and petioles, dark gray water soaked lesions are formed
which later become slightly sunken and dark black; and /or
- Slightly sunken, dark gray irregular lesions are formed on fruits that
Fig 13. Symptoms of
The disease spreads under cool and rainy conditions but the development
is limited under low humidity conditions. The disease is prevalent in the rainy
season. In the rainy the disease spreads rapidly and destroys the plants in a few days after initial occur-
Control: The Control Measures recommended for Late Blight are:
- Fungicides such as Ridomil, Phosal 80 WP will effectively control the disease;
- Straw or grass mulch is effective for the decrease of the disease incidence; and /or
- Disbudding and defoliation of tomato plants should be avoided when its rains.
FUSARIUM WILT (F.W.)
The causal agent is Fusarium oxysporum
Symptoms: The symptoms of F.W. are:
- Initially, lower leaves show wilting and yellowing and droop slightly;
- Later, yellowing develops on upper leaves and the plants are almost dead;
- Browning appears up to the higher part of the stem vessel (Figure 14);
- Root rot wilt occurs under cool conditions.; and /or
- Browning of stem vessels is restricted to the stems near the soil surface but roots show severe
browning and decay.
The casual fungus survives in soil within debris of infected leaves
and roots. It produces spores, which can survive under adverse
environments for a long period of time in soil.
Control: The control measures recommended for F.W are:
- Continuous cropping should be avoided;
- Plant resistant varieties;
- Graft seedlings on resistant rootstocks;
- Soil fumigation - Treat planted area with Rhizolex; and /or
- Plant on ridges.
Fig 14. Symptoms of
SOUTHERN BLIGHT (S.B)
The causal agent is Sclerotium rolfsii
Symptoms: The symptoms for S.B are:
- White silky and thread-like mycelia appear on the stems near the soil
surface and around the stem (Figure 15);
- Brown and black rot of the stem, which develops near the stem line;
- The infected plants show poor growth, wilt and eventually die (Figure
The fungus can survive for years as sclerotia in soil and host debris. The
movement of soil or infested plant material can disseminate sclerotia.
Fig 15. Infected stem due
The optimum temperatures for disease development are in the range
to southern blight
of 25 - 35°C.