A look into Pepper production...

Pepper is popular in Zimbabwe especially as an additive to gravy/soups or relishes. Peppers

generally are sold through the retail markets although they can be found at open vegetable
markets. Wholesale buyers include Favco, Selby, and Willowvale wholesale amongst a host
of retailers who also pack and resell the crop. The most popular types of peppers in the
market are green and red peppers. Peppers are not difficult to grow but must not be planted in
frost-prone regions. This production guideline provides growers with information on how
best to grow peppers.
Cultivars
Peppers that are frequently grown are varieties of C. frutescens, which are the peppers
commonly grown in the vegetable garden and include those from which red pepper, cayenne
pepper, tabasco, and paprika are made. There are many varieties of garden peppers. They are
divided into two main groups: the sweet peppers or mild-flavoured varieties, which are used
for stuffing, salads, and garnishing; and the hot peppers, which are mainly used in sauces and
flavouring. The Spanish word “Chili” describes peppers of all kinds, but in English, the name
is usually only applied to the pungent varieties used for flavouring. C. frutescens grossum,
the sweet or bell pepper, is a popular vegetable. Certain types of peppers are very beautiful
when grown as potted plants, especially in the late summer and early winter. The best are C.
frutescens cerasiforme, the cherry pepper and C. frutescens conoides, the cone pepper. The
varieties of these kinds have red, purple or cream-coloured fruit.

Climatic requirements
Pepper is a warm-season crop, which performs well under an extended frost-free season, with
the potential of producing high yields of outstanding quality. It is very vulnerable to frost and
grows poorly at temperatures between 5 and 15 °C. The optimum temperature range for
sweet pepper is 20 to 25 °C. The germination of pepper seed is slow if sown too early when
soil temperatures are still too low, but seedling emergence accelerates as temperature
increases to between 24 and 30 °C. The optimum soil temperature for germination is 29 °C.
Low temperatures also slow down seedling growth, which leads to prolonged seedling
exposure to insects, diseases, salt injury or soil crusting, any of which can severely damage or
kill off the seedlings.

High temperatures adversely affect the productivity of many plant species including green
pepper. Sweet pepper requires optimum day/night temperatures of 25/21 °C during flowering.
The exposure of flowers to temperatures as high as 33 °C for longer than 120 hours leads to
flower abscission and reduced yields. Pollen exposed to high temperatures (>33 °C) normally
becomes non-viable and appears to be deformed, empty and clumped. Temperatures lower
than 16 °C can lead to fruitless plants. Higher yields are obtained when daily air temperature
ranges between 18 and 32 °C during fruit set. Persistently high relative humidity and
temperatures above 35 °C reduce fruit set. Fruit that is formed during high-temperature
conditions is normally deformed. Sweet peppers are also very sensitive to sunscald. Fruit
colour development is hastened by temperatures above 21°C.
Soil requirements
Bell peppers prefer deep, fertile, well-drained soils. Avoid planting in low-lying fields next to
streams and rivers because these sites are subject to high humidity and moisture conditions
and, therefore, especially prone to bacterial spot diseases. Producers should also avoid fields
where long residual corn or soya bean herbicides have been used because herbicide carry-
over can cause serious damage to peppers. Pepper fields should be located as far away from
tobacco plantings as possible owing to potential spread of aphid-transmitted viruses from
tobacco to peppers. It is also advisable not to grow peppers after other solanaceous crops
(such as tobacco, tomatoes, potatoes, and brinjals) or vine crops for a period of three years
because all of these crops are susceptible to the same diseases. Peppers do extremely well
following fescue sod. Use a soil test to determine fertiliser and liming requirements. Peppers
grow best at soil pH between 6.0 and 7.0. Adjust the soil pH to near neutrall (pH 5.5-6.0) for
maximum yields. To reduce the risk of Verticillium wilt and other diseases, avoid using fields
in your rotation in which egg-plant, tomato, pepper, potato, and strawberry, or caneberry have
been planted.

Land preparation
Avoid growing peppers on the same soil more often than once in 3 or 4 years. As tomatoes
and peppers are subject to the same diseases, neither should follow the other in successive
seasons in the same soil. Soil used for plant beds should have had no peppers grown in it for
4 or 5 years, preferably never before.
Planting
Greenhouse peppers are sown in October through February for harvest of fruit approximately
five months later in March through July.
The exact time to maturity varies depending on the variety of pepper. Most sweet peppers
mature in 60 to 90 days after planting; hot peppers can take up to 150 days. Keep in mind,
however, that the number of days to maturity stated on the seed packet refers to the days after
transplanting until the plant produces a full-sized fruit.

Spacing
Although much of the greater part of the total area of all kinds of peppers is grown from
transplants, seed can also be sown directly in the open field, principally in some of the
warmest parts of the country. Ten to 12 seeds can be planted 45 cm apart on rows that are 75
cm apart and later thinned to 2 plants per stand when 8 to 10 cm tall. One hectare requires
100 to 200 g of seeds. The costs of production by direct sowing are nearly the same as those
by transplanting, because of the cost of more seed, thinning, and additional cultivation to
control weeds. Direct sowing is not generally recommended, even in places where the season
is long enough to permit its use. The seedbed for raising seedlings is made 120 to 150 cm
wide and as long as is necessary. The soil is pulverised by forking and breaking up the clods
and removing stones and straw.

Fertilisation
 basal fertiliser Super C (6:24:20 8S 0.1B) should be applied at a rate of 500 kg per hectare at
planting. At 5, 10 and 14 weeks after transplanting, apply as top dressing 200 kg/ha of
Ammonium Nitrate, 150 kg/ha of Muriate of Potash, 300 kg/ha of compound J (14:6:20), and
100 kg/ha of Calcium Nitrate.

Irrigation
Many growers of fresh-market peppers plant the crop under black plastic mulch with trickle
irrigation under the plastic. This provides uniform moisture and fertilisation during the
growing season. Dry conditions result in premature small-sized fruit set, which leads to
reduced yields. Sweet peppers have a total water requirement of about 600 mm and a weekly
water requirement of 25 mm during the first five weeks and 35 mm thereafter. Excessive
rainfall or water supply can negatively affect flower and fruit formation and eventually lead
to fruit rot. Unrestricted water supply to the crop can be as harmful as inadequate water. Root
rot diseases can be caused by waterlogged conditions that last for more than 12 hours.
Therefore, drainage of the field is very important. If plant growth is slowed by water stress
during flowering, flowers and immature fruit are likely to drop off.

Irrigation is essential in arid and semi-arid regions to provide enough water for pepper
production. Furrow irrigation is well known as a major factor favouring conditions leading to
the development of diseases like bacterial wilt. Drip irrigation is one method of water
application that optimises water supply for pepper production and conserves water in arid
regions. Drip irrigation with cultural practices like mulching generally leads to additional
yield increases. Drip irrigation allows for frequent application of low levels of soluble
nutrients to the root zone (fertigation). The control over the root environment with drip
irrigation is a major advantage over other irrigation systems. Sprinkler irrigation requires
good quality water. However, this type of irrigation is likely to make bacterial diseases more
of a problem through splashing.

Weed control
Good weed control in peppers should start before the crop is planted. Control established
perennial weeds before planting peppers in the field. Use cultural, mechanical, and chemical
weed control techniques in a coordinated manner to reduce the risk of interference with the
crop. Plastic and organic mulches control weeds effectively. Higher plant density can also
smother weeds. Shallow cultivation will help to avoid root damage especially around young
plants. Weeds growing up through the planting holes of plastic mulch can be a particular
problem. Recommended herbicides include Command 4EC, and Paraquat/Agriquat. For
Nustedge control , apply Basagran 480 EC.

Pest control
Aphids
Aphids can make pepper fruit unmarketable because of the honeydew that is secreted by the
aphid and/or associated sooty mould fungi. Infested plants can be stunted, with deformed
foliage. Green peach aphids are variable in colour and have a wide host range. Aphids
overwinter as eggs on crop residue or host plants. The winged forms which are less
frequently found than wingless forms, enable the insect to move into new areas. Females can
reproduce without mating with males. Aphids are generally most abundant from mid-summer
through October. Their severity is greatly influenced by weather patterns.
 Greenhouse infestations of transplants can be minimised by practising good greenhouse
sanitation. Controlling weed hosts around the edges of fields may help to control aphid
infestations. Crop debris should be destroyed as soon as possible soon after harvest.

European corn borer

European corn borer larvae tunnel into and feed on fruit, causing direct damage, premature
ripening, and entry points for fruit-rot pathogens. Infested fruit may appear unaffected on the
outside but are damaged internally. Cultural control is achieved by locating pepper fields as
far away as possible from maize fields. Eliminating weeds around field edges will make
pepper fields less attractive to ovi-positing females. Post-harvest control practices include
destruction of pepper residues and ploughing in the fall to destroy overwintering larvae.

Mites
Mite feeding damage is expressed as downward curling of leaves, giving an inverted spoon
shape and suppression of lamina development of young leaves, and causing the leaves to
become narrow. Affected leaves develop a bronze appearance, especially on the lower side,
and they become thickened and brittle. Heavy infestations may kill off the apical meristems.
Fruit develop a rusted, corky surfaces and may be distorted. Weeds, e.g. nightshade that serve
as hosts for the mites, should be controlled to reduce infestation. Several insecticides provide
effective control of mites. The recommended chemical control is Imidacloprid 200SL.

Thrips
Thrips damage includes distortion and upward curling of leaves, developing a boat-shaped
appearance. The leaves become crinkled and the lamina may be reduced, resulting in narrow
leaves. The lower surface of the leaves develops a silvery sheen that later turns bronze,
especially near the veins. Damaged fruit is distorted with a network of rusted streaks. Control
measures include the use of resistant cultivars and mulching with plastic. Apply Fenveralate
20 EC, Lambda 5 EC, Thionex 50 WP, or Decis 2.5 EC to control thrips.

Cutworms
Cutworms can be contolled with Decis 2.5 EC, Fenveralate 20 EC, or Lambda-
Cyhalothrin 5 EC.

Disease control
Bacterial leaf spot (Xanthomonas campestris pv. vesicatoria)
Bacterial leaf spot is the most economically significant disease of peppers. The causal
bacterium infects both pepper foliage and fruit. Leaf spots first appear on the undersides of
leaves as small, irregular, water soaked areas. The spots grow large, become purplish-grey
with black centres, and may have a narrow, yellow halo. Affected leaves become ragged, turn
yellow and drop off. Spots on fruit are like blisters, becoming rough and cankerous and often
extending into the seed cavity, predisposing the fruit to secondary pathogens. Loss of foliage
also predisposes the fruit to sunscald. An increasing number of resistant varieties with good
horticultural characteristics are becoming available to producers. Also practise a two-year
rotation away from tomato and pepper crops.
Seed should be certified and disease-free. A seed treatment using bleach may help provide
control. Good field sanitation should be practised to minimise the spread of the disease.
Planting disease-free transplants is a key step in managing this disease in the field. Most
growers have switched from overhead irrigation to drip irrigation in part to minimise the
spread of Bacterial leaf spot (BLS). Crop debris should be destroyed as soon as possible
 soon after harvest to prevent disease carry-over to other plants and to initiate decomposition.
Apply Copper Oxychloride 85% WP to control Bacterial leaf spot.

Powdery mildew
The symptoms are chlorotic spots on the upper leaf surface. Numerous lesions may coalesce,
causing chlorosis of the leaves. Lower leaf surface lesions develop a necrotic flecking and
generally, but not always, are covered with a white to grey powdery growth. It progresses
from older to younger leaves, and leaf shedding is a prominent symptom. The disease is
promoted by warm weather (dry and humid). Fungicides are used to manage the disorder.
Wettable Sulphur, Benomyl 50 WP, Nimrod, or Shavit 25 EC are all effective remedies.

Anthracnose
Anthracnose can be controlled with Dithane M 45 or Copper Oxychloride 85 WP.

Physiological disorders
 Blossom-end rot
Blossom-end rot (BER) is a common disorder of greenhouse peppers, with the symptoms
occurring in the pepper fruit. The disorder is associated with a number of environmental
stresses as well as calcium deficiency. Any condition which causes water stress or a reduction
in transpiration, and resultant movement of nutrients through the plants can cause symptoms
to develop. Lack of water, fluctuating soil water conditions, damage to the root system, and
high electrical conductivity in the root zone can cause blossom-end rot. An actual calcium
deficiency to the plant is rarely the primary cause of the disorder as BER can develop when
adequate levels of calcium are being fed to the plants. The environmental factors that can
trigger the disorder interfere with the movement of calcium within the plant, causing less
calcium to reach the fruit. Some cultivars are more prone to this disorder than others.

Symptoms of blossom end-rot begin as soft spots on the fruit, which develop into sunken,
brownish to tan lesions with a very distinct border between affected and healthy tissue. The
spots usually occur on the bottom third of the fruit and are not strictly confined to the bottom,
or blossom end of the fruit. Affected fruit is unmarketable. Control is obtained by avoiding
conditions of moisture stress or conditions of reduced transpiration in the crop. Simply ensure
that the plants receive adequate water and that the vapour pressure deficits (VPD) targets are
met. Weekly foliar applications of calcium nitrate can have a significant impact on reducing
the occurrence of BER. Apply Calcimax foliar sprays to correct calcium deficiencies.

 Fruit cracks
This condition is characterised by the appearance of very fine, superficial cracks on the
surface of the pepper fruit, which gives a rough texture to the fruit. The development of these
cracks is associated with sudden changes in the growth rate of the individual fruit. The
appearance of fruit cracks can follow periods of high relative humidity (over 85%), changes
from hot, sunny weather to cool, cloudy weather or vice versa. Maintaining a consistent,
optimised growing environment is the best way to prevent the development of fruit cracks.

 Fruit splitting
The development of large cracks in the fruit is a direct response to high root pressure. Factors
that contribute to the development of high root pressure directly impact on fruit splitting.
Ensure that optimal vapour pressure deficit (VPD) targets are met at all times. Adjust the
timing of the last watering in the day so as not to water too late. Eliminate any night-watering
cycles.
 Fruit spots
The appearance of small, white dots below the surface of the pepper fruit is associated with
excess calcium levels in the fruit and the subsequent formation of calcium oxalate crystals .
Conditions that promote high root pressure will also favour the development of fruit spots.

 Misshapen fruit
The development of misshapen fruit is generally associated with suboptimal growing
conditions at flowering and pollination, which result in poor flower development or poor
pollination. Ensure that optimal environmental conditions are met and maintained to reduce
or eliminate the development of misshapen fruit.

Harvesting
Yields of 6 to 10 ton/ha of bell peppers may be obtained for processing. Fresh market yields
may range from 500 to 1 000 cartons (12 kg) per hectare. When using appropriate plastic
culture techniques, yields of 1 428 cartons (12 kg) per hectare have been reported. Pimiento
and dried chilli pepper yields range from 1 to 2 ton/ha. Pepper yields are greatly influenced
by the number of harvests and season. As peppers mature, their walls thicken. Pick peppers
when the fruit is firm and well coloured. In some areas, bell peppers are generally hand
harvested as green mature fruit. For the fresh market, or when the fruit is to be stored,
peppers should be cut cleanly from the plant, using a hand clipper or sharp knife, leaving
about a 2 cm section of the pedicel (stem) attached to the fruit. A clean cut is important as
such cut surfaces heal more quickly. This reduces incidence of decay in storage and during
transport to the market. Care should also be exercised to ensure that the stems do not cause
puncture wounds in harvested fruit.

Maturity is determined when the fruit is smooth and firm to the touch (it is a function of wall
thickness). Bell peppers for the fresh market must also be 8 cm in diameter and not less than
9 cm long. They can also be harvested red, which are considerably sweeter and more
flavourful. Mature yellow, orange and purple bell peppers, together with red bell peppers
represent a generally high-value product in fresh market channels. Cherry peppers are
machine harvested most successfully. Cherry types are harvested as both green and red fruit
and the banana types are generally harvested as yellow, mature peppers. Jalapeño and some
cherry peppers have been machine-harvested successfully in other areas. Machine harvesting
may be successful with other types, especially where the peppers are intended for processing.

Harvesting Methods
Peppers are generally broken off from the plants with the stems left attached to the fruit. For
sweet peppers, strong cloth picking bags which are suspended from the shoulders of the
pickers are preferable to baskets or boxes. This frees both hands for rapid and careful removal
of the fruit from the plants. Picking in containers that have hard and rough surfaces may
result in damage to the peppers.