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With the proper care and a favourable rootstock, a citrus tree is capable of producing fruit in excess of 50 years!

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OrangesOrangesCitrus trees can be so pretty, even in the smallest of gardens. They have gorgeous shiny green leaves, beautiful sweet-smelling flowers, and wonderful health-giving fruit packed with vitamin C and antioxidants. The genus Citrus is native to south-east Asia, occurring from northern India to China and south through Malaysia, the East Indies and the Philippines, and records of domestication go back to about 500 BC.

Citrus is big business in South Africa and we are the second-largest exporter of oranges, grapefruits and lemons in the world. Citrus is grown in three different climatic regions; the cool coastal areas of the Eastern and Western Cape, Kwa-Zulu Natal, the semi tropical areas of Limpopo and Mpumalanga, and tropical areas like Nelspruit and Letaba. The Sundays River Valley, north of Port Elizabeth in the Eastern Cape, is world-renowned for being able to produce almost any kind of citrus, thanks to both its special climatic conditions and its location in a valley, not too close to the sea. Despite its hot summers, which allow the area to produce fruit with high sugar content, the Eastern Cape is regarded as a cool citrus producing area, with the cold, frost-free winters assuring good colour development. Both of the above results in the excellent quality of the navel oranges and lemons it produces. The Sundays River Valley takes the traveller into an evergreen world of citrus trees, and in October when the trees are in full bloom, the warm air of the Valley is heavy with their perfume.

With the proper care, good cultural practices, and a favourable rootstock, a citrus tree is capable of producing fruit in excess of 50 years. One such example is the original Washington Navel orange brought first from Brazil to Washington D.C. - then to California - in 1873. One hundred years later it was still alive and producing fruit.

In the Garden: Citrus do need quite a bit of tender loving care, but will reward you with bumper crops if their specific needs are met; and by choosing different varies, will provide you with fresh citrus for up to nine months a year. Citrus make the perfect evergreen garden tree and grow beautifully in pots in courtyards or on balconies. Any variety can be grown in a tub, providing the container is a decent size. Generally, Kumquats and Calamondins are very well-suited to tub-culture, as are Meyer Lemons and Lime trees. Of all the lemons for pots, you can't get much better than the 'Meyer'. I't's got a really nice tight bunching habit and produces plenty of fruit. It is not as acidic as the 'Eureka' lemon, is full of juice and great for cooking. If you are planting citrus in a pot, use a good quality potting mix and water and feed regularly.

Selecting Citrus for Your Garden:

The first step toward successfully growing citrus trees is to take the time to find out which varieties grow best in your area and to purchase them from a reputable nursery. Citrus trees are subtropical to tropical in nature and they suffer severe damage or even death because of freezing temperatures. However, several types of citrus have sufficient cold-hardiness to sustain some freezing conditions, particularly as mature trees. The tree you select should have healthy, deep green leaves, the trunk should be straight and the tree should be able to support itself without a stake. Young grafted trees will start producing fruit when still very young, but it is best to remove all fruit until the trees are more mature; fruiting takes a lot of energy from the young tree and by removing it, the plant can conserve energy, allowing it to adapt to the stresses of its new environment and grow new roots and leaves.

Good citrus yields are particularly dependant on both summer and winter temperatures. For the best quality fruit, the temperatures should not be too hot in summer, or too cold in winter. In colder regions plant them in a warm sheltered position in the garden away from cold winds and cover them in winter if necessary, until they are established. A nearby reflective wall, fence, or even patio can provide both shelter and extra warmth. Lemons are semi-hardy to moderate frost and other citrus cultivars are available that have been bred to be more resistant to cold, so check your varieties carefully.

In regions that experience moderate frost (-3°C to -5°C) you can grow Lemons, Kumquats, and Satsuma Mandarins in a very sheltered part of the garden, or in large pots on sheltered patios. Cover young plants with a protection cover in winter until they are established.

In regions with mild winter frost (-1°C to -2°C), Lemons and certain varieties of Valencia and Navel Oranges, Naartjies, Satsumas, Clementines, Mandarines and Kumquats can be grown in a sheltered position. Calamondins will tolerate brief spells of frost.

Fruiting & Harvesting: With the exception of lemons, which flower up to four times per year, most citrus varieties flower in spring. The buds appear in early August, and by early October the last petals fall, leaving the tiny fruitlets behind. A mature citrus tree can produce hundreds of thousands of blossoms, yet only about two percent of these will result in edible fruit. This heavy blossom production is nature's way of assuring that insects, attracted by the tree's fragrance, pollinate the maximum number of flowers. Seventy to eighty percent of the flowers will drop during and immediately following bloom. A second drop of small pea-sized fruits a couple of weeks after blooming will occur; this is perfectly natural.

Depending on the variety, a citrus tree is capable of producing anywhere from 1 to 1000 pounds of fruit per season. Maximum yields will vary according to the variety grown, weather conditions, cultural care, the age of the tree, and many other factors. Fortunately, the fruit from citrus trees does not mature in the span of a few weeks as deciduous fruit does. Most citrus fruit should be allowed to ripen on the tree, and the longer it remains on the tree, the less acidic and sweeter it will become. Ripened fruit will hold on the tree for 3 to 4 months, allowing you to harvest as required. Oranges, lemons, and grapefruit should all be completely free of green colouring as they will not ripen off the tree. Limes are generally picked green, so go by size and season.

Growing Citrus: Generally citrus can be planted all year round, except in colder regions where it is best to avoid planting in the winter months. Spring is the main season for growers to plant their open rooted and potted trees, but in regions where the spring weather warms up very quickly, planting in late summer and autumn (March to April) will give the young trees ample time to become established before the temperatures become too hot. Citrus form small, compact evergreen trees, and are usually slow growing. The best site is a warm sunny spot, protected from strong winds; trees grown in semi shade will not bear as much fruit and the tree will be more susceptible to disease and insect attacks. Most citrus grows well in a soil pH range from 6 to 8. Avoid soils that are excessively salty, as citrus trees will not grow well in such soils. Excellent drainage is essential, as they do not like waterlogged roots. Citrus have a shallow root system, with feeder roots close to the surface of the soil, so any cultivation around them must be quite shallow. Organic mulches must be kept at least 30cm away from the trunk of the tree because of their potential for inducing foot rot disease and bark infection. 

Watering: How often you need to water your citrus trees will depend on the composition of the soil, how well it drains, and your rainfall. They grow best when they are flooded with water and then allowed to dry out before re-watering. Overwatering can be just as much of a problem as not watering enough. During the summer months, established trees can be watered deeply about every 7 to 10 days and in winter every 2 to 3 weeks. Newly planted trees will require more regular watering until they are established. Water well during dry, warm weather, or they may prematurely drop their flowers or developing fruit. Once established, the trees may tolerate some drought, but the quality of the fruit will be affected.

Planting: Planting your citrus tree at the proper depth is the most important factor. Plant the tree too low and the trunk will stay wet, and this will encourage bark diseases. Plant it too high and the root ball will dry out too quickly and not enough moisture will get to the tree. Young citrus trees must be planted in deeply dug, well drained soil with added compost, but no fertiliser. Young trees should not be fertilised until they start showing new growth. The practice of scooping out grass and soil to form a large depression for ease of watering, almost guarantees the death of a citrus tree. Try to avoid planting citrus in the middle of the lawn, as the lawn will compete for moisture and food and your tree may become stunted, unless it is given extra care.

Feeding: Established citrus trees require moderately heavy nutrients and even on very fertile soils will require feeding after a few heavy crops. Feed them three times a year - in July, December and March - with a balanced fertiliser that has a high nitrogen and medium potassium level (8:1:6 is fine for the home gardener.) During the first few years of growth, give your tree 300g at each application and then increase it to 500g. Gradually increase this amount yearly, until your tree is fully mature and receiving 2,5kg per application. In addition, give the tree 75g of Epsom salts (magnesium sulphate) three times a year. Mature, bearing citrus trees should receive enough nitrogen to provide for good but not excessive leaf growth. Never fertilise close to the trunk and spread it uniformly on the soil surface under the tree canopy to slightly beyond the drip line, and water it in thoroughly. It is not necessary to drill holes in the soil for fertilisers as a thorough watering will carry surface-applied fertiliser throughout the soil.

Pruning: Citrus trees do not require severe pruning and can be allowed to grow naturally, as much as is practically possible. Pruning citrus can be beneficial for fruit production when it is done in such a way as to allow more light and air to penetrate the canopy of the tree.  Allow your trees to branch as low down as possible, if you prune your branches too high your tree will produce less fruit. Aim to have four to six well-positioned, scaffold branches by the first year of bearing. These scaffold branches grow laterally from the tree trunk, providing the framework of the mature tree. In subsequent years, remove extra scaffold branches and thorny water shoots, as well as any suckers growing from the rootstock below the graft. Pruning is also done to remove dead, diseased or damaged wood. Any strong upright shoots which are taller growing than the rest of the tree will eventually bend forward. If you must remove this strong growth, cut out the branch completely, as shortening it will only aggravate the problem. "Wild" shoots that are growing beyond the general shape of the tree can also be removed. These will often be long, straight, quick-growing branches that don't follow the overall form or shape of the tree. Seal all large cut branches with a good tree sealer to avoid infection.

Weeds: All weeds need to be removed regularly by hand, because the shallow feeder roots and trunk are easily damaged by tools; and wounds promote the penetration of soil pathogens in the plant, causing root rot. Weeds also act as pathways for ants.

Propagation:

Citrus trees are not grown from seeds because plants grown from seed are not always true to the parent plant and you can never be certain what kind of plant you are going to get and how well it will produce. Citrus naturally have a weak rootstock, so they are grafted onto a stronger more vigorous rootstock.

CITRUS VARIETIES: Citrus in South Africa are divided into cultivar groups and each cultivar group has unique climatic requirements and are dependent on temperature, heat units, day length, light and humidity.

Calamondins & Kumquats (Citrofortunella X mitis & Fortunella japonica)
These garden hybrids are beautiful ornamental trees that produce abundant crops of miniature fruits for a long time. They are grown for their ornamental value and to make preserves. Standard plants are available that look wonderful planted in tubs. They will grow about 2m tall and 2m wide and are semi-hardy to frost if they are planted in a sheltered place.

Lemon (Citrus x limon)
Lemons are the most useful garden trees and are native to South East Asia. Lemon is used in drinks, and for flavouring a wide variety of foods. The essential oil from Lemon is known as cedro oil, and is used as flavouring in the food industry and is also used in soaps, detergents and perfumes. Lemons are easy to grow and will tolerate colder weather than other citrus, but the trees will be damaged if the temperature drops to -7°C at night.  'Meyer' is best in colder regions, and produces heavy crops of smooth fruit with a thin rind, on almost thornless stems. 'Eureka' is a very popular variety that grows taller than 'Meyer' and is also a heavy cropper, producing large, smooth-skinned fruits with few or no pips; it is also almost thornless. Other varieties include: 'Lisbon', 'Genoa' and 'Limoniera'. The trees will grow about 3m tall and 2 to 3m wide. The 'Cape' or 'Rough' lemon (Citrus jambhiri) is very thorny, with a thick, rough skin.

Limes
Limes originate from tropical Southeast Asia, where they can still be found growing in the wild. There are several varieties, each with its own characteristic flavour. Cultivars have been developed based on sweetness (usually sour), size, shape (round or oblong) and colour (yellow or green). All varieties have relatively thin skins. Lime fruits are used for preserves, garnishes and juices, and Citral oil is extracted for use in perfumes.

The Persian Lime, Tahiti Lime, Bearss Lime (Citrus latifolia)
The seedless fruit is about 6cm in diameter, often with slightly nippled ends, and is mainly used for fresh consumption. It is usually sold quite green, but turns yellow as it reaches full ripeness. The Persian lime is larger than the Key lime and thicker-skinned, but is not as aromatic, and is less acidic. The trees are only suitable for frost-free regions and will grow about 2 to 4m tall and 2 to 3m wide.

The Key Lime, West Indian Lime, Mexican Lime (Citrus aurantifolia)
The Key Lime is valued for its unique, tart flavour compared to other limes. It is smaller, seedier, has higher acidity, a stronger aroma, and a thinner rind than that of the Persian lime. It is usually sold quite green, but turns yellow as it reaches full ripeness. It is used mainly for its juice and rind oil production, for preserving, and to a lesser extent, fresh consumption.

ORANGES (Citrus sinensis)
Oranges are native to China and South Vietnam. They are highly ornamental garden plants that look beautiful even without fruit.

Navel Oranges only produce good quality fruit in cool subtropical and temperate Mediterranean climates. They mature early and are great dessert oranges because they are seedless, are relatively easy to peel and have excellent flavour. They are not as productive as Valencia oranges and severe climatic conditions during flowering and fruit set can negatively impact on yields. Early maturing navels like 'Navelina' and 'Newhall' are harvested in April and May. Mid maturing varieties like 'Bahianinha', 'Palmer', 'Cara' and 'Washington', are harvested in May and June. Late maturing navels like 'Lane Late', 'Cambria', 'Glen Ora' and 'Witkrans'are harvested in June and July. Navel oranges vary in height according to the variety, but will grow about 5m tall and 3 to 5m wide.

Valencia Oranges are ideal for the home garden. The fruit is smaller than navels with a thinner rind and few seeds, and no navel. They are very sweet and are good for juicing and eating, even though they are more difficult to peel than navels.  They have a high acid content and mature later than navels. The early maturing varieties like 'Turkey' and 'Benny' are harvested in June and July, the mid maturing varieties like 'Midknight' and 'Delta' in July and August, and the late maturing varieties like 'Du Roi', 'Valencia Late' and 'McLean' from July to September. Valencia oranges vary in height according to the variety, but will grow about 5m tall and 3 to 5m wide.

Seville, Bergamot or Sour Orange (Citrus x aurantium)
The sour orange is a hybrid between 'Pummelo' (Citrus grandis ) and 'Mandarin' (Citrus reticulate). It originates in China and the oldest written records appeared around 300 BC. Because of its bitter taste, the sour orange is not usually eaten raw, but rather for making marmalade and candied peel. It is also used to produce essential oils for use in soaps and perfume, for fruit extracts that are used to flavour soft drinks, and in distilling certain liqueurs.

Mandarins, Tangerines, Naartjies & Tangelos (Citrus reticulata)
Mandarines, tangerines, tangelos and naartjies are all interrelated. The Mandarin was probably domesticated in tropical Southeast Asia. By 500 BC it was known in China and by 400 AD grafting methods were being used to clone favourable varieties. It was introduced to Japan at an early stage, and it was here that the Satsuma variety was developed.

Mandarins produce delicious fruits with loose rinds and are best suited to regions with cool to cold winters, where the temperatures do not drop below 5°C. They don't do well in hot tropical and subtropical regions. Varieties include: 'Satsuma', 'Clementine', 'Nova', 'Empress' and 'Tambor'. The trees will grow about 3 to 4.5m tall and 4,5m wide.
 
Tangelos were bred from Mandarin 'Deliciosa', which was crossed with a grapefruit to produce a tasty, firm, red-skinned hybrid that is called a Tangelo. The 'Orlando' and 'Minneola' tangelo originated as a cross between a 'Duncan' grapefruit and a 'Dancy' tangerine. Tangelos generally have loose skin and are easier to peel than oranges. They are easily distinguished from oranges by a characteristic knob at the top of the fruit. The fruits are the size of an adult's fist and have a tangerine taste, but are very juicy, producing excellent and plentiful juice. Several cultivars of Tangelo have been developed; like 'Minneola', 'Orlando', 'Seminole' and 'Sampson'.  They will grow about 4.5m tall and 3.5m wide.

Tangerines and Naartjies fruit best in regions where the winter temperatures do not drop below 5°C and will grow about 3 to 4.5m tall and 4.5m wide. Varieties include: 'Cape', 'Fagan', 'Groenskil' and the Japanese 'Satsuma' and 'Oonshu'.

Grapefruit (Citrus x paradisii)
Grapefruit is a West Indian hybrid that is widely grown commercially and in gardens. They thrive in frost-free areas and the fruit develops best in subtropical regions. The trees get quite large, 3 to 6m tall and 3m wide, and are only suitable for large gardens. They are distinguished by their high acid levels and large fruits. 'Red Blush' and 'Rosa' have a lovely pinkish flesh with good flavour and size. 'Star Ruby' and 'Flame' have red flesh, and 'Marsh's Seedless' has white flesh, and 'Marsh' has white flesh and 'Marsh's Seedless' has very large, sweet fruit.

Shaddocks (Citrus maxima)
Shaddocks are also called Pummelo or Pamplemousse and are thought to have originated in South East Asia. They are generally larger than grapefruit, with lower acid levels and firmer juice vesicles.

CITRUS DEFICIENCIES:

YELLOW LEAVES: It is not uncommon for citrus leaves to go yellow during winter or after a heavy cropping of fruit and this can be corrected in spring with fertilisation. Yellowing can also occur if the ground is too wet and the drainage is not excellent. Mineral deficiencies can also cause a yellowing and mottling of the foliage and it is usually a deficiency of iron, zinc, magnesium or manganese that is causing the problem. Zinc deficiency shows a fishbone-like pattern on the leaves with a yellowing between the leaf veins.Manganese deficiency cause yellow blotches between the leaf veins. Magnesium deficiency is fairly common, especially in autumn. The leaves will go yellow with a green V-shaped area at the base leaf. To correct this give a mature tree 2,5kg of magnesium sulphate (Epson Salts) and for a young tree about 250g. Iron deficiency Citrus may exhibit Iron deficiency in the early spring. Usually the deficiency clears up as the soil warms up. If it does not, a soil application of iron chelate should sort out the problem. Clay soils usually contain plenty of iron, but where iron deficiency does occur, do not use fertilizers which contain phosphorous because high phosphorous aggravates iron and zinc deficiency in high pH (alkaline) soils. Red, sandy soils may need supplemental potassium and sandy soils may need additional zinc. Nitrogen: Mature citrus trees should receive enough nitrogen to provide for good but not excessive leaf growth.

PESTS & DISEASES: The use of pesticides in the home garden should be restricted to a minimum and whenever possible, organic products should be used. There is a natural balance in nature between pests and their natural predators, and when pesticides are used continuously this balance is disturbed, and a vicious cycle is created; resulting in the trees having to be sprayed all the time. Apart from the damage caused to the environment, the cost factor can also be enormous. Insects occasionally trouble citrus trees in home gardens and may require spraying, but rarely will these pests render the fruit inedible or seriously threaten the health of the plant. Good cultural practices will help to keep insects and diseases to a minimum and citrus can easily be grown organically. If you do have spray, always use organic products and follow the dilution rates and spraying times meticulously and always add a wetter/sticker to the spray mixture. Citrus leaves are very glossy and a sticker helps the spray stick to the leaves.

Ants: The brown house ant and the pugnacious ant are the one of the most important insects to control near citrus trees, because they protect and 'farm' certain insects like scale and aphids, for the honeydew they secrete. Ant nests, particularly those of the pugnacious ant, if present underneath or near the trees, must be treated immediately. Ludwigs Insect Spray is a broad spectrum insecticide that contains garlic juice, canola oil and natural pyrethrum. It is certified to control ants and many other garden insects. Canola oil kills small-bodied insects on contact by means of suffocation, and garlic keeps insects away from plants. Pyrethrum has a stomach poison activity of about 24 hours. This formulation has a very low toxicity to mammals, with no secondary poisoning. It is however, toxic to fish and moderately toxic to bees. Edible crops can be harvested 48 hours after applying.

Scale Insects: There are many types of hard (armoured) and soft scale insects, and they can be various colours, like brown, red, purple, grey, white,  green etc. Pernicious and red scale, as well as soft brown scale are a common problems on citrus as well as many other garden plants, and can be present all year round. A sure sign that you have scale is if there are ants running up and down the branches. Young scales are mobile crawlers and adult males have tiny wings, making them more mobile than the females. Mostly, the adults attach themselves to the bark, leaves and fruit, sucking out the plant sap through their needle-like mouthparts.  Scale insects generally excrete honeydew, on which a fungus called sooty mould grows. Sooty mould is black and looks worse than it really is, and doesn't hurt the leaves or fruit. Scale insects are 'farm' by ants for their sugary excretions, and in return, the ants protect the scale from their natural predators like; ladybirds and their larvae, lacewings and predatory thrips. Many types of scale are controlled satisfactorily by their natural enemies, provided ants are kept out of the trees, get rid of the ants around your trees and the sooty mould and the scale will disappear. Severe infestations can cause the leaves to turn yellow and drop and may kill young trees. It will cause die-back of the twigs and can kill entire branches on more mature trees. To control bad infestations, remove all badly infested branches completely in winter and burn them. The best time to spray for scale is also in winter but mineral oils can be sprayed in summer, as long they are applied during the coolest part of the day. Mineral oils like Oleum work the best, killing most species of scale on contact. If infestations are very severe you should apply three applications within 10 days, ensuring full coverage of the tree. Products containing Canola oil, like Margaret Roberts Insecticide will also suffocate scale. Ludwigs Insect Spray is a broad spectrum insecticide that contains garlic juice, canola oil and natural pyrethrum. It is certified to control many garden insects. Canola oil kills small-bodied insects on contact and garlic keeps insects away from plants. Pyrethrum has a stomach poison activity of about 24 hours. This formulation has a very low toxicity to mammals, with no secondary poisoning. It is however, toxic to fish and moderately toxic to bees. Edible crops can be harvested 48 hours after applying.

Brown Citrus Aphid: Aphids are soft-bodied insects that suck the sap from plants and can therefore spread viral diseases from one plant to another. Young aphids are wingless and adults can be winged or wingless. The various species vary in colour and can be dark brown, light and dark green, red-brown, pale yellow, grey and black. The aphids secrete honeydew which attracts ants and other insects. The ants farm the aphids for the honeydew, and in return, protect the aphids from their natural predators such as ladybirds, parasitic wasps and praying mantis. Aphids love fresh new plant growth and can cause distorted and malformed growth, and stunting of the plants growth. Black sooty mould is a fungus that grows on the honeydew, but this fungus will not damage the leaves or fruit. Get rid of the aphids and ants and the mould will disappear. Margaret Robert's Organic insecticide controls small-bodied insects and is authorised for use in organic agriculture. It contains garlic juiced extract and canola oil and is used to control aphids and many other garden insects. Canola oil kills small-bodied insects on contact by means of suffocation, and garlic keeps insects away from plants. It has a low impact on bigger bodied beneficial insects and natural predators and the product is harmless to fish, birds, wildlife, pets and humans. However, never allow oil formulations to form a layer over water surfaces as huge quantities of any oil will cut off the oxygen supply to aquatic organisms, resulting in harm to aquatic life like fish and frogs. No harmful toxic residues remain in the environment for prolonged periods and edible crops can be harvested within 24 hours.

Citrus Thrips: Severe attacks by thrips will cause young shoots and leaves to become thickened and distorted, and developing shoots may turn black and fall off. During development, the peels of young citrus fruit can also be blemished by citrus thrips. This mostly starts from the stem end and may spread downwards, extending over the rest of the fruit, but does not, however, affect the eating quality of the fruit. Ludwigs Insect Spray is a broad spectrum insecticide that contains garlic juice, canola oil and natural pyrethrum. It is certified to control thrips as well as many other garden insects. Canola oil kills small-bodied insects on contact by means of suffocation, and garlic keeps insects away from plants. Pyrethrum has a stomach poison activity of about 24 hours. This formulation has a very low toxicity to mammals, with no secondary poisoning. It is however, toxic to fish and moderately toxic to bees. Edible crops can be harvested 48 hours after applying.

Citrus Psylla: Psylla causes unsightly bumps on the leaves, especially the fresh young leaves, and is caused by citrus gall wasps. They are the transmitter of a major citrus disease known as greening. (See Greening). Citrus trees have three growth flushes a year: one in August/September, followed by another in November/December and the last during February/March. Lemons are the exception, forming new leaves throughout the year. It is during these flushes that the trees are susceptible to psylla infestation. The female citrus gall wasp lays discernible orange-yellow eggs on the edges of the young leaves. When the eggs hatch, the young nymphs move to the underside of the leaves and establish themselves to feed, causing pock-like malformations on the leaves. Control of the pest must be aimed at destroying the nymphs as soon as possible after they have hatched. Because all the eggs do not hatch at once, it is essential to use a spray with a fairly long residual action and to spray regularly - as subscribed on the bottle. Check your trees regularly for the eggs and begin spraying immediately, ensuring that all the leaves are thoroughly covered.

Citrus Leaf Miner: Leaf miner attacks can occur at any time of the year, especially in warm and humid regions, causing the leaves to curl and go brown, with distorted twisted new growth, and squiggly lines in the leaves. This pest can really make the trees look unsightly. There are several types of leaf miner and tiny moths, beetles or flies are the adult stage. Damage to plants is done at the larval stage, when they feed within the leaves, and heavy infestations will affect yields. Leaf miners need to be controlled, especially in young trees, by spraying every time they put out a new flush of leaves. The insects can be found on weeds, flowers and vegetables, so keep the ground around your trees weed- free. The best control is obtained when infestations are detected at an early stage. Physically removing infected leaves will  help control larvae growing inside the leaves, and spraying with a contact poison containing Canola oil or natural Pyrethrins will control the adults, if sprayed weekly. Ludwigs Insect Spray is a broad spectrum insecticide that contains garlic juice, canola oil and natural pyrethrum. It is certified to control many garden insects. Canola oil kills small-bodied insects on contact and garlic keeps insects away from plants. Pyrethrum has a stomach poison activity of about 24 hours. This formulation has a very low toxicity to mammals, with no secondary poisoning. It is however, toxic to fish and moderately toxic to bees. Edible crops can be harvested 48 hours after applying.

Citrus Mealybugs: There are many mealybug species; they are small white, oval insects that are covered in mealy waxy threads. They can be found on the undersides of the leaves, the leaf joints, and crevices, where they are not easily noticeable. Mealy bugs are a common garden pest. They suck the sap of plants and can therefore transmit viruses. If infestations are severe, they can cause severe wilting of the soft, new shoots, leaf discolouration and severe leaf drop, yellow spots may develop on citrus fruits.  The sweet honeydew they secrete will cause sooty mould to grow on their secretions. Sooty mould looks worse than it really is and doesn't hurt the leaves or fruit. Mealy bugs are protected and 'farmed' by ants for these sugary excretions. If you get rid of the ants, so that the natural predators of mealy bugs can help control their populations, the mealybugs and the sooty mould will disappear. Natural predators of mealybugs are ladybirds, parasitic wasps, lacewings and small birds. Mealbug infestations can occur at any time of the year and winter is an ideal time for them to breed in sheltered areas of the garden. Spring and late summer are the best months to spray for control because their natural predators may also be affected by sprays and they are not as active in the cooler months. Mealybugs can be treated with the same pesticides as for scale and aphids. White mineral oils like Oleum and organic insecticides containing canola oil and natural pyrethrins are effective, suffocating the insects on contact. Ludwigs Insect Spray is a broad spectrum insecticide that contains garlic juice, canola oil and natural pyrethrum. It is certified to control many garden insects. Canola oil kills small-bodied insects on contact and garlic keeps insects away from plants. Pyrethrum has a stomach poison activity of about 24 hours. This formulation has a very low toxicity to mammals, with no secondary poisoning. It is however, toxic to fish and moderately toxic to bees.Edible crops can be harvested 48 hours after applying.

Fruit Flies: Fruit flies attack many species of fruiting plants and cause post-harvest decay on fruit. Fruit flies look like a small housefly and the clear wings have orange and brown patterns. When they rest on fruit the wings are usually horizontal. In South Africa the most common species are the Mediterranean and Natal Fruitfly. Infestations can occur all year round but seem to peak from January to March. They sting the fruit and lay their eggs just below the surface, right after the blossoms have fallen, as well as when the fruit is ripening. The eggs hatch within three days and the small white maggots begin feeding. Signs of fruit fly infestation will show as a sticky gum oozing out of the still green fruit. After a few weeks the fruit is entirely rotten and falls to the ground. The maggots then burrow into the soil to pupate. Within two weeks a new generation of fruit fly emerges and a new cycle begins. There are several eco friendly ways to combat this destructive cycle. In May or June brush the tree trunks and any large branches of your fruit trees with a medium hard brush to remove hibernating insects. Remove all mulch and fallen debris from the ground and burn it. In spring, when your trees start to bloom, place a lining of frost cover/ bidum/weed guard on the ground around your trees. This will prevent mature fruit fly, that have survived the winter in the soil, from emerging from the ground. Once 80% of the blossoms have fallen from your tree you can start spraying with wormwood and garlic or a quassia spray every week. Spray the entire tree as well as the ground around it. Try to do this in the early evening when the bees are in their hives. Organic formulations like Ludwigs Insect Spray contain pyrethrins and can also be applied every 2 weeks. Baited traps can also be hung in the trees.Continually remove any fruit that appears to be stung and keep good hygiene on the ground.

Orange Dog Caterpillars: These can sometimes become a problem in the garden, especially on immature trees, because the larvae feed mainly on the young leaves. The damage caused is the same as for any leaf-eating caterpillars, but seldom will the larvae reach epidemic proportions and a few caterpillars on mature trees will not affect the health of the trees. The culprit is a beautiful butterfly called the citrus swallowtail, which emerges in spring. It has large wings with bright yellow and black markings, with the distinctive swallowtail at their bases. The spiny backs of the young larvae are black with a white mark. As the larvae mature they become smoother and turn green, with a diagonal black stripe on both sides of the back, and black stripes across the head.  They can reach 40mm long and larvae can be present from late spring to autumn.  If only a few are present, they can be collected by hand or you can spray with Margaret Roberts Biological Caterpillar Insecticide, which is a natural product that will control orange dog caterpillars as well as many other garden insects. It contains no toxic residues and is harmless to bees, birds, fish, pets, wildlife, beneficial insects and natural predators. It can cause harm to the young larvae of butterfly species, but has no effect on adult butterflies. It is safe to use on edible crops and they can be harvested directly after application.

Sooty Mould: This fungus looks worse than it really is and doesn't hurt the leaves or fruit. This fungus grows on the sugary deposits made by scale insects, aphids and mealybugs, which are protected and farmed for their sugary excretions, by ants. Get rid of the ants and the mould will disappear.

Citrus Black Spot: is common in tropical to subtropical regions. This fungal disease affects many garden plants and is most noticeable on roses if the humidity is high and during prolonged wet weather, especially in autumn. Infection shows on the leaves by the appearance of dark brown to black spots, followed by a yellow radiance around the edges and can result in leaf drop. Mancozeb 800 WP is an organic fungicide which controls black spot and many other fungal diseases on edible crops. Scab usually becomes less of a problem as the trees grow older, but routine spraying may often continue to be necessary, particularly on the more susceptible varieties.

Scab: This fungus that can affect the leaves, twigs, and fruit, of susceptible citrus varieties. It can be particularly severe on lemon trees and also occurs on minneolas, tangelos and grapefruit, but rarely on sweet oranges. The symptoms are a corky roughness on the leaves and young twigs. The disease starts as small, pale orange, roughly circular, elevated spots that develop well-defined protuberances on one side of the leaf, often with a conical depression on the opposite side. The tops of these wart-like growths usually become covered with a scabby, corky tissue, and the infected spots can often run together, covering large areas. The leaves of badly infected plants become crinkled and distorted and the twigs will develop small masses of similar corky outgrowths on the surfaces. Scab starts on the fruit by forming irregular scabby spots or caked masses that start off cream to pale yellow and develop to a dull olive-grey with age. Bad infections will cause the fruit to become misshapen, with wart-like or conical growths extending from the surface. On grapefruit the infected areas tend to flatten out, resembling wind scar injury. The spores are spread by rainfall, heavy dew, irrigation systems, and to some extent by wind. Warm, wet summer weather is ideal for spore germination, when the temperatures reach 24 to 28°C. To control scab two to three applications of fungicide need to be applied. Citrus scab is similar to apple and pear scab and is treated in the same way. The trees should be sprayed in early spring when the first flush of new leaves is a few centimetres long. The second application is made at petal fall, and the last one is applied about 3 weeks later. Mancozeb 800 WP is an organic fungicide which controls scab and many other fungal diseases on edible crops. Scab usually becomes less of a problem as the trees grow older, but routine spraying may often continue to be necessary, particularly on the more susceptible varieties.

Blossom-end Rot: causes a brown patch of rot on end on the ripened fruit where the blossoms were attached. It is mainly caused by the fruit being over-mature on the tree.

Phytophthora: This is a serious disease that affects citrus. It affects the lower trunk and/or root system of the plant. If this fungus is present in your soil, it can cause infection and every time the tree is watered these pathogens can silently invade the roots and lower trunk tissues. This disease is most active when the soil is not allowed to dry out sufficiently between watering, and especially if the lower trunk area is the last part to dry out.

Foot Rot: is a fungal disease present in many South African soils. Both sour orange and trifoliate orange rootstocks have some resistance to the disease, so it is not a problem unless the tree is planted too low and the bud union is exposed to the soil or is standing in water.

Tristeza: This is a virus disease that kills citrus trees quickly, particularly those growing on sour orange rootstock.

Greening: Greening is prevalent in the relatively cooler, high-lying areas (above 600m). Typical symptoms are yellowing of the leaves and malformed fruit. One side of the fruit does not develop normally and remains smaller, resulting in asymmetrical fruit. The smaller side remains greenish while the rest of the fruit turns orange. The disease is caused by a bacterium for which no chemical treatment is available. It is transmitted by psylla (see Citrus psylla). As greening is usually localised within one or two branches of the tree, it is advisable to completely cut out the infected branches. Saw them off as close to the trunk as possible. If the entire tree is affected, it would be better to remove and replace it.


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