Spots on
leaves angular in shape and variable in size due to leaf veins that
limit their enlargement. Initially, spots are water-soaked. In moist
weather, bacteria ooze from the spots in tear-like droplets, which dry
making the tissue white. Affected leaf dries and shrinks, and it may
tear away from the healthy portion leaving irregular holes. Leaves
approaching maturity are more susceptible than older leaves. Fruits may
also be attacked. Fruit spots are small, nearly circular and
superficial. The bacteria survive in association with seed. When
infected cucumbers are used for seed extraction, the seed can be
contaminated during fermentation process. The bacteria can also survive
in soil or infected crop debris. Drainage water can spread the bacteria
in the soil.
Angular leaf spot disease is favoured by wet conditions, frequently associated with rainfall and overhead irrigation. Optimum temperature for disease development is 23.9 to 27.80C. The disease attacks watermelon, gherkin, muskmelon, pumpkin, squash, and vegetable marrow.
What to do:
Use resistant varieties, if available.
Use certified disease-free seed.
Practise crop rotation. A crop rotation of 1 to 2 years is recommended.
Avoid run-off water from nearby cucurbit fields and overhead irrigation.
(Sphaerotheca fuliginea and Erysiphe cichoracearum)
Credits: Biovision -Infonet
Powdery mildew on peas (c) A. M. Varela, icipe
Symptoms first develop as a whitish talcum-like powdery growth on upper leaf surface. The powdery growth is composed of fungal spore mass. These areas covered by white powdery growth may enlarge and join up to cover both lower and upper leaf surfaces. Severely affected leaves dry, turn brown and become brittle. Vines can be also attacked. Secondary effects of the disease include sun-burning and premature ripening of fruits.
Powdery mildew affects watermelons and all other cucurbits. Other hosts include African violets and pawpaws. The powdery mildew fungi are influenced by plant age, humidity and temperature. Foliage is most susceptible 16 to 23 days after unfolding. The fungi reproduce under dry conditions. Infection increases as humidity increases, but does not occur when leaf surface is wet. Optimum temperature for infection is about 27.40C. However, infection can take place at a temperature as high as 320C and relative humidity as low as 46%.
What to do:
Use resistant varieties, if available
Spray with sulphur based fungicides, which provide good control. Do not apply sulphur fungicides when is hot – it may cause burning of foliage.
They cause reduced plant stand (population). Diseased seedlings exhibit rotting and death of infected roots. A white cottony growth appears on affected tissues. Loss of young plants occurs through damping-off.
Mosaic virus on watermelon (c) A. M. Varela, icipe
Zucchini yellow mosaic potyvirus on Cucurbita pepo. ZYMV provokes in cucurbit crops very severe symptoms of stunting, yellowing, necrosis (occasionally), mosaic, leaf deformations, fruit discolourations and deformations. (c) Courtesy EcoPort S. Pone
Many viruses affect the cucurbit family. The important viruses include cucumber mosaic virus, watermelon mosaic virus and zucchini yellow mosaic virus. Field symptoms of these 3 diseases are similar and therefore it is very difficult to separate them by symptoms alone. Leaf symptoms include a prominent light and green mosaic pattern, mottling (yellow with green islands or blisters), and in severe cases, leaf distortion whereby affected leaves appear fern-like. Diseased fruits are malformed (slightly to severely misshaped with wart-like lumps).
Cucumber mosaic virus (CMV) It is not seed transmitted except through seed of perennial wild cucumber (Echinocytis lobata) and chickweed (Stellaria media). It is mechanically transmitted and in nature it is spread by various species of aphids (e.g. Aphis gossypii, Myzus persicae, etc.). The transmission mode by aphids is of the non-persistent type: the aphids acquire the virus from an infected plant and then transmit it to a healthy plant with their probing. They can acquire CMV from an infected plant in 10 to 30 seconds and can transmit the virus after feeding for as few as 9 seconds. It is also transmitted by striped cucumber beetles (Diabrotica vittata) and 12-spotted cucumber beetles (D. undecimpunctata) by mechanical means in plant sap carried on their mouthparts. It has a very extensive host range including such varied species as bananas, carrots, cowpeas, lupine, lilies, onions, passion fruit, potatoes and tomatoes.
Watermelon mosaic virus [Papaya ringspot virus-watermelon strain (PRSV-W), Watermelon mosaic virus 2 (WMV-2)] [p]This virus is mechanically transmitted and also spread by several species of aphids in non-persistent mode. It is not seed transmitted. Its host range is primarily restricted to cucurbits although one of its strains infects peas.
Zucchini yellow mosaic virus (ZYMV). ZYMV is transmitted from one plant to another by aphids (e.g. Aphis gossypii, Myzus persicae, etc.) in non-persistent mode and by mechanical inoculation. The virus is not seed-borne.
What to do:
Use tolerant or resistant varieties if available.
Remove infected plants (disinfect hands and tools with 70% alcohol after contact with infected plants).
Do proper weeding.
Control insect vectors. A sustainable approach of controlling aphids is to prevent aphids reaching the crops and transmitting the virus.
In case of squash mosaic virus use certified disease-free seed
Flea beetlePhyllotreta mashonana feeding on young okra pod. (c) A.M. Varela, icipe
They are tiny to small (1.5 to 3 mm) long leaf beetles with well-developed hind legs. They are named for their habit of jumping like fleas when they are disturbed. The colour of the adult beetles varies from black, brown, black and yellow striped or metallic blue-green depending on the species. Adult flea beetles chew small round holes (shot holes) in leaves, giving them a sieve like appearance. On rare occasions, they may feed directly on ripe fruit, just below the calyx. This damage is usually seen only in plants that show extreme foliar stress resulting from lack of water or powdery mildew. The larvae of flea beetles live in the soil and feed on roots, but the damage caused is not of economic importance. Adult flea beetles can be particularly damaging to young plants. Seedlings are most vulnerable to flea beetle feeding when stressed, particularly by inadequate moisture. Older plants can withstand considerable leaf perforation.
What to do:
Monitor the crop frequently, particularly during the first stages of the crop. Even a small flea beetle population can cause significant damage to a crop in the cotyledon or first-leaf stages
Provide good nutrition and favourable growing conditions. This helps to avoid plant stress from diseases and moisture, and helps plants survive flea-beetle attack.
Weed in and around fields. This may help to eliminate flea beetle shelter and breeding grounds, reducing crop damage.
Keep plant diversity in the farm. Living mulches or polycultures are known to reduce flea-beetle damage. Diversity in the farm support populations of natural enemies.
When necessary spray botanicals or other alternative products. Extracts of neem, rotenone, pyrethrin, sabadilla, garlic, onion and mint alone or in combination have been recommended for control of flea beetles. Insecticidal soap is reported to give partial control of flea beetles. However, sprays combining rotenone with insecticidal soap are considered very effective. Diatomaceous earth and rock powders have been observed to reduce flea-beetle populations but applications must be renewed regularly after rainfalls.
Good health in the rabbitry comes from keeping the environment clean, dry and well-ventilated and avoiding overcrowding.
The
problem of disease is two fold in domestic rabbits. The first and most
important part is prevention, the second concerns elimination and
treatment of disease when it occurs. A healthy rabbit should recover
rapidly from minor ailments and the keeper must direct every effort to
assist the recovery and also to enable the rabbit to resist disease.
Hygiene and sanitation play a big part in good management. Quarantine new rabbits
Rabbits should be allowed direct access to sunlight as it also acts as a germicide besides having a beneficial effect
Destroy the affected rabbits in any outbreak. These complications can only be overcome by the keeper’s vigilance.
Prevention
of disease is not a subject to which one should turn only when disease
appears, that is usually too late. It must form part of the rabbit
keepers day to day management.
Some diseases spread so quickly that action must be taken immediately. Complete isolation of sick rabbits is essential. Early treatment is the only effective method of dealing with disease. A decision has to be made as to whether the rabbit can be saved and, if it can, is it financially viable to do so. If the rabbit is to be destroyed, it should be done humanely, away from the rabbit unit, and the carcass should be incinerated without cutting it up as this could spread bacterial infections through the unit. A farmer may well be able to diagnose the problem, but it is advisable to seek veterinary advice in the event of a disease outbreak. Prevention and treatment of common disease, along with hygienic measures are necessary to avoid outbreaks. One can often draw conclusions from the symptoms with regard to the location and type of disease, along with the chances of recovery.
Early recognition of disease is most important as there is more chance of recovery if the treatment is started early. It is quite useless to commence treatment when the disease has progressed to the stage that the rabbit is obviously dying. A watchful rabbit keeper will be quick to notice any change in appearance of any of his stock.
A fall in weight is one of the first signs
that all is not well. The reason for slow weight gain, loss of weight or
lack of appetite should be sought.
A good keeper will notice any change in the feces.
The
coat is a good indication of a healthy rabbit. A dry, dull, harsh or
patchy coat indicates something is wrong. A sleek, glossy coat indicates
good health.
A healthy rabbit is alert. Any
sudden noise or movement will awaken its immediate interest. The
rabbit’s movements should be free and easy and it should not sit huddled
in a corner.
It’s breathing should be even.
The respiration rate of an adult rabbit is 30 – 50 breaths per minute.
Shallow (rapid) breathing is an indication that something is wrong.
The eyes should be bright with no discharge from them or from the nostrils, mouth, vent, anus or teats.
The
rabbit should not feel ‘bony’ and the muscles along either side of the
spine should be firm and full, with no swellings, which are indicative
of cysts or abscesses.
A healthy rabbit is full of vitality and the farmer should aim to keep his rabbits like this.
Causes of diseases
Diseases may be caused by:
Bacteria: Diseases of the rabbit caused by this group though relatively rare, include pasteurellosis in various forms and tuberculosis.
Viruses: Few diseases are caused by these organisms, the most common being myxomatosis which is not seen in East Africa
Animal parasites: Includes single celled animals or protozoa which produce coccidiosis, flukes, flatworms and roundworms. In this group are also fleas, lice, ticks and mites which can produce disease such as ear canker or, alternatively, can carry disease.
Nutritional deficiencies: A shortage of vitamins, minerals and other essential items of food which give rise to ailments such as rickets, reproductive failures and other problems.
The spread of diseases
Diseases can be spread by physical contact, confinement of healthy animals with diseased stock, contamination of feed, by rodents and birds and through water and the air. Many potentially harmful organisms are present in the animal’s body in such small numbers that symptoms of disease do not manifest themselves, provided the animal has a good resistance and a well working immune system. The disease will only appear if the rabbit is subjected to challenges such as bad feeding, cold or any other stress factor
Common Rabbits Diseases
Some of the commonly occurring diseases in rabbit units are:
a) Coccidiosis
This is probably the most common disease in rabbit
units. Once a farm is infected with coccidiosis, it is very difficult
to eliminate it completely or permanently. It is difficult to cure
hepatic coccidiosis.
Symptoms:
Anorexia (not eating)
Pendulus and distended abdomen followed by progressive weakness, diarrhea, constipation and jaundice
Prevention:
It is best prevented in well constructed rabbit units, where the rabbits are not living in cramped, crowded or dirty conditions.
Cages should be disinfected at regular intervals and cleaned daily. Nest boxes should be disinfected between kindlings.
Water bowls and feeders must be cleaned and disinfected regularly.
Treatment: All the drugs used are prophylactic (preventing infection) and should be given when there is risk of disease. There are many coccidiosis preventative drugs on the market in East Africa, most of them for poultry, but these are suitable and effective in rabbits.
b) Pasteurellosis (snuffles)
The bacterium Pasteurella multocida causes a variety of diseases in rabbits. These include: snuffles, pneumonia, otitis media, conjunctivitis and abcesses. Snuffles is not a fatal disease but the animal can develop pneumonia, pleurisy or acute pasteurellosis as secondary infections. The disease may migrate from the nasal cavity through eustachian tube to the middle ear, causing inflammation and may lead to torticolis, uncoordinated gait, inability to take food and water and loss of weight. This particular disease does not respond to treatment.
Symptoms:
In snuffles, the main symptom is a thick sticky, white discharge from the nose which the animal wipes away with its fore legs.
There is also constant sneezing, which will encourage the spread of the disease.
Prevention:
Avoid cold draughts in the house.
Construct rabbit hutch according to the recommendations.
Treatment:
Snuffles and pneumonia can effectively be treated by a combination of penicillin and streptomycin administered intramuscularly by injection.
c) Pneumonia
It is caused by poor housing, overcrowding and poor ventilation especially in cold areas. Ensure that there is sufficient bedding to prevent draughts coming through the floor, and that the rabbits are not subjected to cold winds, especially at night. It is advisable to have the ends of the units protected with plastic or heavy duty shade netting. It is also advisable to have roll down ‘curtains’ over the front of the unit, made of plastic or shade netting, that are let down at night to keep the whole unit warm.
d) Conjunctivitis
P.multocida goes from the nasal cavity to the eye through tear duct and causes reddening of the conjunctiva and a discharge from the eyes.
Treatment:
It can be treated with antibiotic ophthalmic ointments and drops.
e) Abcess
Subcutaneous and visceral abscesses are quite common in rabbits. Subcutaneous multiple abscesses may be found on the face, body and lower jaw containing thick cheesy pus. Visceral abscesses however, may be found on the liver, heart and lungs. They may cause sudden death
Prevention/ Treatment:
Drain the abscess of all pus.
Irrigate
with a solution of hydrogen peroxide and water, flush again with saline
and then irrigate with iodine. If the abscess has been drained
completely, one treatment may be sufficient. The hole will close
spontaneously.
f) Sore hock
Ulcerated sores will develop on the back leg joint (the hock).
Prevention/ Treatment:
Keep the cages clean. Dirty wet cages are the source of the infection.
Open the ulcerated sores and clean thoroughly.
Apply antiseptic dressing.
Failure to treat will certainly be fatal.
g) Heat prostration
If the temperature soars beyond 35 degrees
centigrade, the rabbits will become restless. They will start panting
and blood will ooze from the nostrils followed by death.
Prevention:
The only way to prevent this is to transfer the animals to a cooler situation.
h) Hind quarter paralysis
Sudden disturbance, fear or excitement may leave rabbits paralysed. They become helpless creatures and their activity is restrained. There is no cure for this deadly disease. The breeder should avoid strangers entering the unit for curiosity and fun.
i) Hairball occlusion
Sometimes fur and wool are accumulated in the stomach, blocking normal passage of food. This may be cured with mineral oil or surgery.
k) Incurable diseases
The following diseases are incurable and culling is the only way out:
Infections arthritis (thickening of the knee, hip, shoulder)
Kidney fibrosis
Leucosis (enlargement of liver, spleen, lumph nodes, whitish tumour foci in liver )
Geographical distribution of Watermelon in Africa. Updated on 4 July 2019. Source FAOSTAT
General Information and Agronomic Aspects
Watermelon (Citrullus lanatus) is a member of the cucurbit family (Cucurbitaceae), which also includes cantaloupes, cucumbers, pumpkins, squash, zucchini and butternuts. It is indigenous to the dry plains of tropical and subtropical Africa, perhaps in the general area of present day Botswana. It is one of the most widely cultivated crops in the world. Its global consumption is greater than that of any other cucurbit. It accounts for 6.8% of the world area devoted to vegetable production. The principal watermelon producing countries are China, Turkey, Iran, United States and Egypt. China produces over 50% of the world supply. China and Turkey have the largest area devoted to watermelon production. FAO lists watermelon production in 101 countries. Watermelon is a good cash crop in Kenya with very good market opportunities, particularly in urban areas. Gross margin per ha for watermelon variety “Charleston Grey” in Embu area of Kenya is Kenya shillings 138,409 (AIRC, 2003).
Watermelons
range in shape from round to oblong or even square as in Japan where
farmers found a way to grow cubic (square) watermelons, by growing the
fruits in glass boxes and letting them naturally assume the shape of the
box. The square shape is designed to make the melons easier to stack
and store, but they are often more than double the price of normal ones.
Rind colour of watermelons can be light to dark green with or without stripes. Flesh colour can be red, dark red or yellow.
The watermelon is often large enough that groceries often sell half or quarter melons. There are also some smaller no more than 3 kg, spherical varieties of watermelon, both red- and yellow-fleshed, sometimes called “icebox melons” or “mini watermelons”
Nutrition
Square watermelon in Japan (c) Laughlin Elkind, wikipedia
A watermelon contains about 6% sugar and 92% water by weight. As with many other fruits, it is a source of vitamin C. Notable is the inner rind of the watermelon, which is usually a light green or white colour. This area is edible and contains many hidden nutrients that most people avoid eating due to its unappealing flavour. Watermelons contain a significant amount of citrulline whose beneficial functions are now being unraveled. Among them is the ability to relax blood vessels, much like “Viagra” does to treat erectile dysfunction and maybe even prevent it. Scientists know that when watermelon is consumed, citrulline is converted to arginine through certain enzymes. The citrulline-arginine relationship helps heart health, the immune system and may prove to be very helpful for those who suffer from obesity and Type 2 diabetes (Texas A & M University, 2008).
Watermelon
rinds are also edible, and sometimes used as a vegetable. In China,
they are stir-fried, stewed or more often pickled. When stir-fried, the
de-skinned and de-fruited rind is cooked with olive oil, garlic, chilli
peppers, scallions, sugar and rum. Pickled watermelon rind is also
commonly consumed in the Southern US. Watermelon juice can also be made
into wine. Watermelon is also mildly diuretic. It contains large amounts
of beta carotene. Watermelon with red flesh is a significant source of lycopene, which is associated with cancer risk reduction. The flesh has an average of 4100 microgram/100 g (range 2300-7200) lycopene
compared to an average of 3100 microgram/100 g in raw tomato, 3362
microgram/100 g in pink grapefruit, and 5400 microgram/100 g in raw
guava.
Varieties
There are over 1200 varieties of watermelons worldwide and a wide
variety of watermelons have been cultivated in Africa. Several of these
varieties have been recommended for Kenya range of climate. These
include:
“Charleston Grey” (open pollinated, matures in 55-60 days, rind colour is light green with light stripes, deep red flesh colour, fruit shape oblong, fruit weight 10-16 kg, tolerant to Fusarium wilt and anthracnose, excellent for shipping, popular in Kenya)
“Congo” (matures in 90 days, round melons reach 16 kg, green stripes, sweet red flesh and thick rinds)
“Crimson Sweet” (open pollinated, matures in 90-120 days, rind colour light green with broad dark green stripes, flesh colour brilliant red, fruit shape blocky oval, fruit weight 7-9 kg, high yielder and good shipping qualities, resistant to extreme heat, popular in Kenya)
“Moon and Stars” (matures in 95 days, dark green skin with yellow spots resembling moon and stars in the night sky, melons weigh 9-18 kg, pink to red flesh)
“Orangeglo” (matures” in 90 days, very sweet and crisp, oblong-shaped melons 9-14 kg, bright orange flesh with off-white seeds)
“Sugar Baby” (open pollinated, matures in 60-75 days, rind colour greenish black, flesh colour deep red, fruit shape round, fruit weight 7-8 kg, very popular in Kenya, suitable for shipping and long transport)
“Sunday Special” (seedless variety, rind colour dark green with black stripes, flesh colour red, fruit shape oval, fruit weight 6-10 kg)
“Orangeglo” ( the oblong shaped fruit weighs 9-12 kg and has sweet orange flesh when ripe. It takes 100 days to ripen for harvest. Read more: https://www.tuko.co.ke/274710-areas-suitable-watermelon-farming-kenya.htmloblong shaped fruit weighs 9-12 kg and has sweet orange flesh matures in 100 days)
“Princess F1” (oval, dark green stripes, matures in 85 days, fruit weighs 8-10 kgs, flesh color is deep red)
“Sukari F1” ( Matures in 90 days, fruits are oblong in shape with an average fruit weight of 7-8 kg , rind colour is light green with dark green stripes. Flesh is deep crimson. Has good transport and keeping qualities. )
Because varieties and market trends change all the time, consult your local seed company, buyer or extension officer for the latest information on the available varieties.
Crimson Sweet (c) A. A. Seif
Sugar Baby watermelons in a trolley in a Nairobi supermarket (c) A.A.Seif
Notice, that on some of the Sugar Baby melons there are yellow patches where the melon has rested on the ground. When this patch turns yellow it means the watermelon has reached maturity. It is not wise to harvest much before the patch turning yellow, as unripe watermelons are such a disappointment to buy.
Ecological requirements
Altitude:
Watermelons can grow at altitudes
of up to 1500 m, Best growing areas are the lowlands with high
temperatures and relatively low rainfall where irrigation may or may not
be necessary
Temperatures:
They grow best under hot temperatures. They do well at temperatures of between 22 and 280 C. Stagnation of growth occurs at temperatures less than 150 C.
Rainfall:
Watermelon production is suited in low to medium rainfall areas with additional irrigation. Optimum rainfall requirement per cropping season is 600 mm and 400 mm is considered minimum. Excessive humidity may favour leaf diseases and also affect flowering.
Sites and soils:
Watermelons grow best on sandy loam soils which are well drained and slightly acid. When planted on very heavy soils, the plants develop slowly, and fruit size and quality are usually inferior. Fine sands produces the highest quality melons when adequate fertiliser and water are provided. Windbreaks are advisable on sandy soils to reduce “sand blast” damage and stunting to young seedlings during strong winds. To reduce the risk of diseases, do not plant on land where cucurbits have grown during the past three years. Well drained heavy soils can also be used. The soils should be rich in organic matter. Watermelon is fairly tolerant to soil pH as low as 5.5. However, a slightly acid soil with a pH of 6.0 to 6.5 is ideal.
Watermelon is known to be sensitive to manganese toxicity, a common problem in low pH soils. Seedling watermelons react to manganese toxicity with stunted growth and yellowish crinkled leaves. Older plants generally exhibit brown spots on older leaves that may be mistaken for symptoms of gummy stem blight. Manganese toxicity is usually associated with soils having a pH below 5.5. However, in wet seasons the condition may occur at higher pH levels when the soil has been saturated for a period of several days. This condition has been noted in several watermelon fields with pH ranges at 5.8 or slightly higher when the crop was planted flat. Planting watermelons and other cucurbits on a bed is good insurance against manganese toxicity during a wet season. The best solution to manganese toxicity is to apply lime at rates based on the results of a soil test.
Propagation
Watermelon is propagated by:
Seeds, directly planted in the field.
Transplants: there is a trend towards greater use of transplants by commercial growers because of the precise requirements for seedless (triploid) watermelon seed germination and the uniformity of the resulting crop. Instead of planting directly in the field and have 3 weeks of accumulated weeds germination and insect attacks to battle with, planting of seeds in seed trays in a protected area for later transplant into the field when at least 2 permanent leaves have developed, is a very viable option. Seed trays of various design and cost are widely available from seed merchants.
Watermelon is grafted in some production areas, most notably in Japan and Korea, where nearly all of the plantings utilise this technique. Grafted watermelon also is widely used in China, Spain, and Italy. Grafting on to rootstocks resistant toFusarium oxysporum and those tolerant of cold soils are the primary reasons for grafting. Popular rootstocks for watermelon are bottle gourd (Lagenaria siceraria), interspecific hybrid squash (Cucurbita maxima x C. moschata), or wild watermelon (Citrullus lanatus var. citroides). Commonly used grafting methods for watermelon are hole insertion, tongue approach, and cleft. With the ban on the use of the broad-spectrum soil fumigant methyl bromide, it is likely that grafting will be used even more in the future and for more uses other than those already invoked. Grafted watermelon plants produce fruit with firmer and redder flesh over a longer period of time. The grafted watermelons produce more fruit per plant with better quality to justify their higher cost. Grafted watermelon, particularly on interspecific hybrid squash rootstock, can grow on soils with higher salt concentrations than non-grafted watermelon can tolerate.
Planting
Watermelons
are grown throughout the year in lowland areas but peaks of rainy
season should be avoided. At higher elevations cultivation should be
done only during the warmer period of the year. The seed rate is about 3
kg/ha. Watermelon seeds germinate best when the soil is very warm
(25-32degC) and the air is almost hot (28 to 33degC), as it is the case
at the end of the dry season. Mix plenty of compost or manure into each
planting hole; at least one shovelful for each hole. Watermelons like
fertile soils high in organic matter. It is recommended that you apply
animal manure (e.g. composted poultry manure or cattle dung) up to 10
tons per ha and rock phosphate before or at planting.
The holes are dug at a distance of about one metre within the row and about 2 metres
between the rows. Plant 2 seeds per hill, placing them 3 to 4 cm (1.5
inches) deep into the soil. Water the hills thoroughly if there is no
rain. At 25-30 cm high earthing up around the plant bases is recommended to prevent exposure to the sun.
For
seedless watermelon production, a pollinator variety is required. Use a
seeded watermelon variety with a distinctly different shape or
appearance from the seedless variety that you are growing. Pollinators
can be planted in rows using a 2 to 1 ratio with every third and outside
row being the seeded variety.
Pollination
Watermelons
produce separate male and female flowers. Male flowers are produced
initially, followed by production of both sexes usually at a ratio of 1
female to 7 males. Watermelon flowers are viable for only one day.
Therefore, it is important that an adequate population of pollinating
insects (bees) are present every day during the flowering period. It
should be noted that watermelon flowers are not nutritionally attractive
to honey bees, therefore, blooming weeds or other crops can out-compete
watermelons in attracting honey bees. Remove nearby flowering plants to
ensure the bees work the watermelon flowers exclusively. Even with
sufficient pollinators, it is not uncommon for watermelons to abort
flowers. Insufficient pollination results in misshapen melons, which
must be culled.
Watermelons, pumpkins, cucumbers, and zucchinis can be planted side by side. Cross-pollination can occur between cultivars of the same crop (e.g. watermelons and watermelons) but not between different crops (e.g. watermelons and pumpkins). Bees are necessary for pollination. Bees need to be present and active in the crop. If bees are not plentiful, then place at least 2 hives/ha, spreading them around the field perimeter and check to ensure that male flowers are producing pollen. Flowers are most receptive to pollination during the morning hours when bee activity is usually the highest. Bee activity is related to climate and is lower in cooler weather. Spraying and irrigation should be coordinated to occur when bees are least active
Irrigation
After
planting, water regularly with plant or manure tea to provide
additional nutrients. Well-filtered teas can also be used in a drip
irrigation system. There are three critical periods where watermelons
need sufficient moisture:
After planting to allow fast and even emergence.
At early bloom to prevent poor fruit set and misshapen fruit.
During fruit development to ensure good melon size.
Do not apply too much water, avoid waterlogging, and minimise wetting of the bed tops. Heavy irrigation or rainfall may also result in fruit splitting.
Weeding
Weeding should be done regularly to keep the field clean. Avoid injuring the plants when weeding.
Fruit pruning
Remove
misshapen and blossom-end rot affected fruits to promote additional
fruit set and better size of the remaining melons. If a market demands
larger melons, remove all but two or three well shaped melons from each
plant. To avoid disease spread, do not prune melons when vines are wet.
Rotation
Watermelons can be rotated with cereals, legumes or cabbages
Harvesting
Harvesting
usually begins 3-4 months after planting. Maturity is sometimes
difficult to determine. Useful maturity indicators are listed below,
however it is still advisable to cut open a few fruits to check maturity
before harvesting commences. The watermelon stem should be cut rather
than pulled from the vine to avoid damage to the stem end. Do not stack
fruit on their ends, as this is where the rind is thinnest. Maturity
indicators include:
A dull hollow sound when the fruit is tapped with the knuckles
The change from white to cream or pale yellow of the skin area where the melon has been resting on the soil.
Shrivelling of tendrils on nodes to which melons are attached.
Slight ribbing on surface of fruit can indicate maturity in some varieties.
The
Brix test is the most objective way of testing maturity. It assesses
the total soluble solids (soluble solids is related to sugar content and
is an indicator of sweetness) of the melon flesh. The test is becoming
more popular with many retailers insisting on specific brix levels
particularly in seedless varieties.
Storage
Ensure
minimum handling of melons, as extra handling is expensive and may harm
the fruits. Watermelons do not store well as they are susceptible to
chilling injury, and are subject to decay at higher temperatures. Under
the ideal conditions of 70C and a relative humidity of 80 to 90 % melons
can be stored for up to two weeks.
Fruit disorders
Blossom-end rot is caused by calcium deficiency and water stress. It is worse in hot, dry, windy conditions where moisture stress is more likely to occur. Symptoms include young fruit drop and brown rotting lesions at the blossom end of older fruit. Good water management and ensuring sufficient soil calcium availability will usually address the problem. Soil or irrigation water salinity may also promote blossom end rot. It tends to occur more readily in oblong varieties. Watermelons having blossom-end rot are unmarketable.
Internal cracking is caused by cool temperatures during early fruit-filling period. Other influences are stop-start growth, excess nitrogen, low boron levels, or heavy infrequent watering at fruit fill. Affected melons tend to be flattened in shape and feel lighter than usual.
Spongy end occurs in melons, which have been poorly pollinated. These melons may turn yellow and drop off the vine early in their development or partly develop with the stylar end soft and spongy. This area is also slightly pointed. Internally, there is very poor seed development at the spongy end.
White heart is white streaks or bands of undesirable flesh in the heart (center) of the fruit. This is caused by excessive moisture (and probably too much nitrogen) during fruit maturation.
Hollow heart is a disorder that varies among varieties. Causes are unknown.
Sunburn occurs most frequently in varieties that have dark green rinds. “Charleston Gray” types and other melons with grey-green rinds rarely sunburn. Good healthy foliage will minimise sunburn as well as favour good yields and quality. Strong winds can blow unprotected vines away from the developing fruit along the edges of the rows and cause full exposure of the fruit to the sun.
Rind necrosis is an internal disorder of the watermelon rind. Symptoms are brown, corky, or mealy textured spots in the rind which may enlarge to form large bands of discolouration that rarely extend into the flesh. Experienced pickers often can detect affected melons by the subtle knobbiness that is visible on the surface of affected melons. The cause of rind necrosis is unknown. Bacterial infection has been reported to be a cause, although similar bacteria are found in healthy melons. Drought stress also is reported to predispose melons to rind necrosis.
The term poultry refers to domesticated birds kept for meat, eggs and feather production. Domestication of poultry is thought to have started in South Asia, at least 2000 years ago. The Asian Red Jungle Fowl is generally assumed to be the ancestor of the modern poultry breeds, but maybe the first domestication of the fowl took place much earlier in China. Following this domestication various breeds have originated from isolated groups of poultry, partly by adaptation to the various environments or cultivation by man. Today’s poultry breeds are all different based on appearance and performance.
Understand chicken as the animals they are, information on behaviour
Chicken are animals with a coherent social structure. If they are in groups up to 25 animals, they have a pecking order based on strength, but they can recognize up to 100 other hens. They communicate a lot both using body, tail and voice. They are hunted and eaten by many, and a large part of their alertness, communication and behavior is about predators and e.g. warning each other against them. This emphasizes their need for being managed in a calm way. As humans, we should never make sharp, loud sounds or sudden movements, when we are with our chicken.
They have a wide range of comfort and grooming behavior, such as preening (maintenance of feathers), stretching wings, and keeping themselves clean and well managed. They have a strong incentive for dust bathing, which is a way of preventing attack of external parasites and as such very important for their well-being. They will normally scavenge for feed, both for seeds, greens, vegetables and worms and other small animals. Their search for feed leads to a lot of ground-scratching and pecking, and they have a great need for this type of behavior. They have a need for sleeping and undisturbed resting, and will find the highest point to be protected. Hens can become ‘broody’ which means that they are highly motivated to have chicken, and become very frustrated if they are not allowed to nest building. On the other hand, they cannot be forced to become broody; some breeds become broody more easily than others. They have a strong sense of being mothers and taking care of their small chicken and protect them.
East African and Kenyan poultry population
Village chicken production systems are mostly based on the local scavenging domestic fowl (Gallus domesticus), which predominates in African villages.
Kenya has an estimated poultry population of 29 million birds, with chicken forming the largest proportion. Of these 76% consist of indigenous chicken, layers 9 %, and 13% broilers. Other poultry species like ducks, geese, turkeys, pigeons, ostriches, guinea fowls, and quails make up 2 % of the poultry population. Poultry is one of the most important livestock enterprises in rural households where over 70% (24 million) of the country’s population live and derive their livelihood. Indigenous chicken are kept by 90% of rural households while broilers and layers are mainly reared by urban and peri-urban farmers who target the ready market. Other poultry are kept by farmers with special interests.
On average, each household in Kenya keeps about 10 chickens, mainly for domestic consumption. There is a relatively high mortality because of lack of drinking water and disease control, and predators. On average, a farmer loses up to 40 percent of their stock annually due to these easily controllable challenges. With proper management practices indigenous chicken can become very productive and have a very good potential for improving the income of the owners.
Village chicken systems in rural Africa are characteristically:
an indigenous and integral part of the farming systems, with short life cycles and quick turnovers
low input production systems, the majority free range chicken
a means of converting low-quality feed into high quality protein
Hybrid layers
Hybrid layers are mostly kept near potential markets for eggs (such as cities and towns) where space is limited but readymade commercial feed are easily available. In non-organic farms, layers are often kept in individual battery cages, but organic poultry are always is free range with outdoor access. In Kenya they are often reared in deep litter houses where there is free movement and perches are provided.
Broilers
Broilers are heavy breeds, often hybrid breeds specially bred for meat production, and bought as young chicks. In organic farms, less fast-growing broilers should be preferred, and they should have outdoor access. Conventional broiler hybrids are very fast growing birds and need specially manufactured feeds and very controlled conditions, and their bones are often weak. These breeds must be discouraged in organic farms, and they should be allowed exercise areas, preferably outside.
Generally, robust and suitable breeds should be chosen in organic herds. It is ethically right to choose animals which can both lay eggs and where the males can be used for meat production. In many industrial countries, the breeds are specific for either egg production or meat production, and this means that e.g. the males from egg producing breeds are killed just after hatching, because they are not good for meat production. This is an ethical dilemma of organic production.
Poultry or poultry products must come from chicken that have been under organic management from the second day of life. If one cannot verify this they are not raising organic chickens.
Organic chicken must not be beak trimmed, which is a practice in some conventional poultry productions.
All feed, except minerals and vitamins, must be organically produced. Non-synthetic vitamins are preferred, but synthetic sources are allowed if non-synthetics are not available.
The following feeds are prohibited:
i. Animal byproducts from mammals and poultry, such as meat and bone meal, are not allowed in feed rations.
ii. Fishmeal is not permitted, (except it can be proved that it is organically produced).
iii. Synthetic amino acids are not permitted.
iv. Non synthetic but non agricultural products are permitted.
Organic guidelines
The handling of feed ingredients must comply with organic requirements. Some people may buy organic feed from mills or grow their own ingredients for feed, but organic guidelines must be followed with either choice.
No drugs may be used to promote growth.
Transporting Live Chicken upside down is not allowed, regardless of the distance
Physical alterations such as beak trimming and toe trimming are not allowed, exceptions could be when the welfare of the animal or flock is threatened. Beak trimming and toe trimming are still discouraged and would be handled on a case by case basis.
Living conditions must be established and maintained to “accommodate the health and natural behavior of animals, including access the outdoors, shade, shelter, exercise areas, fresh air, and direct sunlight. “Continuous confinement is not permitted, but temporary confinement is allowed if adequately justified.
Dust wallows are required, as is clean, dry bedding. Any bedding that is of a type typically consumed by poultry must meet all organic standards.
Birds are not permitted to come into contact with treated wood used to construct chicken pens.
Health care measures must include preventive practices such as good nutrition, sanitation, healthy living conditions and vaccinations. Preventive use of antibiotics is not permitted. Synthetic parasiticides including coccidiostats are not permitted. Although some natural alternative products are allowed, health problems must be controlled primarily through good management.
Birds that do become sick cannot be withheld from medical treatment just to preserve their organic status. They should be medicated and then sold into the conventional marketplace.
Chicken manure must be managed in a way that does not contribute to contamination of crops, soil, or water and that optimizes the recycling of nutrients.
FIVE FREEDOMS FOR CHICKEN WEALTH – IMPORTANT
The welfare of poultry includes its physical and mental state. Good poultry welfare implies both fitness and a sense of well-being for the animal. Any poultry kept by man, must at least be protected from unnecessary suffering. An animal’s welfare, whether on farm, in transit, at market or at a place of slaughter should be considered in terms of ‘five freedoms’. These freedoms define ideal states rather than standards for acceptable welfare. They form a logical and comprehensive framework for analysis of welfare within any system together with the steps and compromises necessary to safeguard and improve welfare within the proper constraints of an effective livestock industry.
1) Freedom from Hunger and Thirst – by ready access to fresh water and a diet to maintain full health and vigor.
2) Freedom from Discomfort – by providing an appropriate environment including shelter and a comfortable resting area.
3) Freedom from Pain, Injury or Disease – by prevention or rapid diagnosis and treatment.
4) Freedom to Express Normal Behaviour – by providing sufficient space, proper facilities and company of the animal’s own kind.
5) Freedom from Fear and Distress – by ensuring conditions and treatment which avoid mental suffering.
Large and numerous swarms continue to threaten the Horn of Africa
The current Desert Locust situation is extremely alarming and represents an unprecedented threat to food security and livelihoods in the Horn of Africa. In addition, important locust situations continue to develop along both sides of the Red Sea, in Oman and in southern Iran.
Kenya. Immature and maturing swarms continue to arrive in the northeast from Ethiopia and Somalia and are moving throughout northern areas in Mandera, Wajir and Marsabit counties and have reached central areas of Isiolo, Meru North and northern Laikipia. Some swarms in the north have moved back into southern Ethiopia while others are now mature and laying eggs that will hatch after about two weeks, giving rise to hopper bands in February and March. Today, a swarm reached the southern Rift Valley near Kapedo on the border of Baringo and Turkana counties. Aerial and ground control operations are in progress in some areas. Further movements are expected, especially in Turkana and Marsabit counties.
Ethiopia. Ground and aerial control operations continue against immature swarms in Somali and South Oromiya regions. Some swarms are maturing while others are moving south and west into the southern parts of the country with at least one swarm reaching the edge of the Rift Valley in Southern Nations Nationalities and People Region (SNNPR). Some 6 000 ha were treated by air so far this month.
Somalia. Control operations are in progress in the northeast (Puntland) while maturing swarms continued to move southwards in central and southern areas. Some swarms were seen laying eggs in the south adjacent to northeast Kenya. Survey and control operations are limited by insecurity.
SouthSudan. There remains a high risk of a few swarms appearing at any time in the southeast (Kapoeta East and Ilemi Triangle) coming from adjacent areas of NW Kenya, flying north through the Rift Valley or northwest from Marsabit county. They may transit through the area to the Rift Valley in southwest Ethiopia.
Uganda. There remains a moderate risk of a few swarms appearing at any time in the northeast from adjacent areas of NW Kenya until about the end of January.
Red Sea. Breeding is in progress and hopper groups and bands are present on the northern coast in Sudan, southern coast in Saudi Arabia, and on the coast of Eritreaand Yemen. Mature swarms are laying eggs on the Sudan/Eritrea border while adult groups have formed in Yemen and Saudi Arabia, some of which are laying eggs. So far this month, ground and aerial control operations treated nearly 23 000 ha in Saudi Arabia and almost 7 000 ha in Sudan.
Oman. Breeding is in progress on the northeast coast where hopper bands have formed. Ground teams treated more than 1 300 ha so far this month. Several immature and maturing swarms are moving south along the coast and reached Salalah. These may continue to Yemen and perhaps reach the Horn of Africa.
Southwest Asia. A few residual immature swarms persist along both sides of the Indo-Pakistan border where control operations are in progress. Adults and swarms were reported to be breeding along parts of the southern coast where heavy rains and flooding occurred earlier this month.
