Back
|
Pineapple
Scientific name:
Ananas comosus
Order/Family:
Bromeliales: Bromeliaceae
Local names:
Nanasi (Swahili)
Pests and Diseases:
Mealybug or pineapple wilt virus
Mealybugs
Pineapple top and root rot
Root-knot nematodes
Sedges
Thrips
White leaf spot
Yellow spot virus
|
Mealybug or pineapple wilt virus
Infected plants become yellowish-red to bright red at the leaf tips, this colouration spreading down the leaf with time. Soon other leaves turn colour and also show signs of wilting. However, the inner heartleaves remain normal. Severely infected plants become stunted and produce small, undergrade and immature fruits. The first effect of the disease usually appears in the roots, which stop growing, collapse and then rot; this results in leaves symptoms similar to the effect of drought. The root system collapses and rots before the first leaf symptoms appear.
The disease is probably introduced with planting material, which may not show obvious disease symptoms. Once established, it is spread by mealybugs, sedentary insects, which are moved from plant to plant by attendant ants. The mealybugs are found at the base of leaves, moving on to healthy plants once their host starts to wilt.
Warm weather favours the build-up of mealybugs and this is when most serious outbreaks of the disease occur. Plants growing vigorously as on virgin land and well-fertilised soil (especially with nitrogen fertiliser) appear to be more resistant to wilt. Adverse growing conditions increase the susceptibility of plants to wilt. Plants may recover from wilt to different degrees, depending on the extent of the wilt and the age of the plant at the time of wilting; younger plants stand a better chance of recovery. Older plants are less susceptible than younger plants, and slips and suckers less susceptible than the mother plant on which they are borne.
- Use planting material from wilt-free areas.
- Control mealybugs. For more information on mealybugs click here
- In Hawaii, heating pineapple crowns in a large water bath at 50°C for 30 minutes permitted 100% plant survival and rendered 100% of the plants free of pineapple wilt-associated-virus. Growth of the heat-treated plants is more rapid than in non-heat-treated plants. The heat-treated plants are not readily colonised by mealybugs, nor do they show mealybug wilt even after more than two years from being planted in a commercial crop with severe mealybug wilt (Ullman et al., 1993).
- Plant resistant varieties if available. Some varieties of pineapple are more resistant to the virus than others, the variety "Cayenne and 'Masmerah' being highly susceptible. 'Singapore Spanish' shows some resistance.
© A.M. Varela, icipe
Mealybugs
Mealybugs
The pineapple mealybug (Dysmicoccus brevipes)
The mealybugs are oval, pink in colour, up to 3 mm long, covered with a whitish waxy secretion, which develops into waxy filaments around the body. This mealybug is the most serious pest of pineapples, because it is a vector of the Mealybug or Pineapple Wilt Virus. The mealybug is common on the roots of pineapple and large colonies develop on the stems just above ground level.
The mealybugs may spread upwards to feed in the floral cavities, on both small and mature fruit, and on the crown leaves. Heavy infestations are conspicuous because of the white waxy adults, which often occur at the growing points, around the stem nodes, on the undersides of leaves, on the fruit and on the roots.
Feeding on leaves causes yellowing and drying up of the leaf-tips, which progresses towards the base of the leaves. Feeding in the blossom cavities causes wounds, which sometimes become contaminated by fungal spores resulting in a disorder called black spot. Feeding on roots is associated with the rotting of roots and subsequent wilting of the plant. "Smooth Cayenne" crowns used as planting material are frequently infested with mealybugs, and therefore new plantations usually become infested from the time of planting.
The bigheaded ant, Pheidole megacephala, is commonly associated with mealybug colonies. They do not attack the mealybugs but feed on the honeydew excreted by the mealybugs, preventing the formation of thick honeydew coats where crawlers (young mealybugs) may get entangled. Moreover, while feeding on honeydew, the ants interfere with the mealybug natural enemies. Thus, mealybug colonies thrive in presence of ants. Mealybug infestations may also be spread into new plantings by ants carrying the young mealybugs from one plant to another in their jaws.
- Control ants to give a chance to natural enemies to keep mealybugs under control.
- See also the section on pineapple wilt virus.
© Courtesy EcoPort (http://www.ecoport.org): Bedford ECG, de Villiers EA
Pineapple top and root rot (Phytophtora cinnamomi and P. nicotianae var. parasitica)
Top rot initially manifests in a colour change of heart leaves from green to yellow or light-brown with a red tinge. The leaf edges curve back and leaves are easily pulled out from the plant. Internally, the stem and leaf bases become soft, rotten and have an unpleasant smell. The growing point of the stem has a cheese-like appearance. Root rot causes similar symptoms like top rot. However, the outer leaves become limp and dieback from the tips. By this stage, the root system has rotten and plants can be easily pulled from the ground. Rot rot often extends through the stem to cause top rot. Fruits from diseased plants are normally small and are not marketable. Both P. cinnamomi and P. nicotianae var. parasitica are soil inhabitants and require water for spore production and infection. These fungi prefer wet soil conditions.
- Do not plant pineapples in soils prone to waterlogging.
- Improve soil by selective rotations and application of organic compost material.
Nematodes (Meloidogyne javanica and Pratylenchus brachyurus)
Root-knot nematodes (Meloidogyne javanica) cause distinct swellings (galls/knots) on the roots. The root lesion nematodes (Pratylenchus brachyurus) develop brown lesions (spots) on the roots, which may girdle the roots and cause their premature death.
- Practise crop rotation
- Allow extended fallow if feasible
- Incorporate neem extracts into the soil
© A. M. Varela, icipe
Thrips (Thrips tabaci and Frankliniella schultzei )
Thrips are small (1.5 mm long), slender, brown insects with pale yellow hind wings that appear as a yellow line down the back of the body when the insect is at rest. Adult thrips have characteristic wings; the transparent wings have a fringe of hairs around the outside edge standing out in the same plane as the wing.
The onion thrips (Thrips tabaci) and the blossom or cotton bud thrips (Frankliniella schultzei) are considered important pests of pineapples because they are vectors of the yellow spot virus, which have been shown to be identical to the tomato spotted wilt virus. The blossom thrips feeds mainly on flowers and its feeding results in the development of "dead-eye" in the fruit. Thrips feeding on the crown of fruits results in concentric ring patterns developing on crown leaves.
- Control weeds in and around pineapple plants as certain weeds leads to increased number of thrips.
- Control thrips in the early stages, in particular immature thrips; adult thrips are unable to pick the virus from infected plants. Once the immature thrips acquire infected with the virus they remain vectors for the rest of their lives.
- Conserve natural enemies. Thrips are attacked by predatory thrips, lacewings and predatory bugs. Avoid use of pesticides that kill natural enemies.
- Whenever necessary spot spray the crop with botanicals or other biopesticides. Some plant extracts (e.g. garlic, rotenone, neem, pyrethrum, and a mixture of garlic and pepper) are reported to control thrips. Spinosad, a bacterial derivative, is effective in controlling thrips. Liquid herbal manure and pyrethrum (in extreme situations) has also been recommended (Naturland, 2001). See also the section on yellow spot virus.
© Courtesy EcoPort (http://www.ecoport.org): Alton N. Sparks, Jr., The University of Georgia
White leaf spot (Ceratocystis paradoxa, Thielaviopsis paradoxa)
The fungus Ceratocystis paradoxa causes white leaf spot, black rot, base or but rot and soft rot or water blisters. White leaf spots are yellow to brown and several centimetres long. Later they dry to become papery and straw coloured.
Base or but rot of pineapple is a common disease of crowns, slips and suckers used for establishing new plantings. Rot of planting material occurs when they are not dried and are packed with little aeration. The fungus also destroys older plants by entering through wounds caused in the collar region while weeding or other field operations. In severe conditions the entire plant may turn dark and rot within 2 or 3 days.
Black rot is a post-harvest disease occurring only on injured pineapple fruit. Only freshly cut or injured tissue is infected, and a soft black rot with dark coloured mycelium develops. Water blisters consist of a soft, watery rot of the fruit flesh with overlying skin glassy, water-soaked and brittle. Eventually, the skin, flesh and core disintegrate and the fruit dries out, leaving an empty fruit carcass containing a few, black vascular fibres. The fungus enters the fruit through wounds and the crevices between individual fruits.
- Use healthy sets of an appropriate physiological age to ensure rapid germination.
- Choose sets with at least 3 nodes to increase the likelihood that the buds towards the centre will germinate before the fungus invades all the tissues.
- Use crop management practices that promote germination and rooting. In disease prone areas, if possible, plant varieties that are quick to germinate. Varieties that are slow to germinate should be treated in hot water (50°C for 2 hours).
- Avoid extremely wet or dry soil conditions.
- Do not plant freshly cut planting material unless dried out.
- To prevent the spread of the pathogen, avoid wounds to tissue and remove infected pineapple plants.
- Improve soil drainage and avoid planting during wet weather.
© Courtesy EcoPort (http://www.ecoport.org): Bureau of Sugar Experiment Stations, Queensland
Yellow spot virus
The yellow spot virus has been shown to be identical to the tomato spotted wilt virus. It infects over a 100 species of plants including peppers, tomato, tobacco, eggplant, potato, broad bean, spinach, chicory and peas. A number of wild plants, including some common weeds such as the black jack (Bidens pilosa), Emilia sonchifolia and Datura stramonium, are also host of this virus.
Thrips are vectors of this virus. When host plants of the virus are grown near to pineapple plants, the incidence of the yellow spot virus is considerably enhanced due to thrips migrating into the pineapple field. Wind carries thrips long distances and thus also plays an important role in the transmission of the virus. One of the symptoms in the fruit is a blackened, dry cavity in the side of the fruit due to one or more "eyes" having died. This is known as "dead eye". Infection of very young fruit results in an irregular arrangement of fruitlets as some fail to develop. Attacked fruits may also fail to develop a crown. Thrips feeding on the crown of fruits results in concentric ring patterns developing on crown leaves. These spots enlarge and the infection spreads into the fruit itself, by which time the crown will often have dried out. The flesh of fruits thus infected will be discoloured and necrotic below the butt of the crown. The whole fruit may eventually become affected.
- Control weeds in and around pineapple fields. This is very important for disease control because the presence of certain weeds leads to increased number of thrips.
- Field management offers potential effective control. Cut off the fruits showing early symptoms of infection. This will prevent the spread of infections into other fruits.
- Where this disease is a problem avoid planting near host plants of the thrips and the virus. Even if thrips are not strongly inclined to migrate from their favoured host plants, they will do so if disturbed, for instance by human passing, animals or machinery.
- Control thrips. For more information on thrips click here
| General Information and Agronomic Aspects | Information on Diseases | |||
| Information on Pests | Information Source Links |
 |
| Geographical Distribution of Pineapple in Africa |
Pineapple is grown for its fruit that is eaten fresh, as dessert, in salads; processed into juice, jam, dried fruits and preserves (crystallised and glace fruit); cooked in pies, cakes, puddings; or used in sauces. Fruits are also canned as slices, spirals etc. Dried pineapple slices are becoming a popular snack in Kenya. The by-products of canning can be used as cattle feed or to produce pineapple wine or vinegar. In the Philippines and Taiwan the fibres from the leaves are woven into a fine cloth. The fruit has high sugar content and is rich in vitamins A and C.
Nutritive Value per 100 g of edible Portion
| Raw or Cooked Pineapple | Food Energy (Calories / %Daily Value*) |
Carbohydrates (g / %DV) |
Fat (g / %DV) |
Protein (g / %DV) |
Calcium (g / %DV) |
Phosphorus (mg / %DV) |
Iron (mg / %DV) |
Potassium (mg / %DV) |
Vitamin A (I.U) |
Vitamin C (I.U) |
Vitamin B 6 (I.U) |
Vitamin B 12 (I.U) |
Thiamine (mg / %DV) |
Riboflavin (mg / %DV) |
Ash (g / %DV) |
| Pineapple raw | 50.0 / 2% | 13.1 / 4% | 0.1 / 0% | 0.5 / 1% | 13.0 / 1% | 8.0 / 1% | 0.3 / 2% | 109 / 3% | 58.0 IU / 1% | 47.8 / 80% | 0.1 / 6% | 0.0 / 0% | 0.1 / 5% | 0.0 / 2% | 0.2 |
Very intensive solar radiation can damage the fruit. Under the full strength of the sun the fruits can develop sunburn, especially when they lodge and are no longer protected by the crown. One method of protection in these cases is binding the leaves around the fruits in order to cover them. However, this is the labour-intensive. Alternatively, the crop can be dusted with lime or diatomite to leave a thin layer of reflecting substance on the fruits/plants.
Pineapple will produce fruit under annual precipitation ranging from 650 to 3,800 mm depending on cultivar, location and atmospheric humidity (RH should range between 70 and 80%). Ideal rainfall for pineapple production is about 1,100 mm. Reasonable yields can be obtained with as little as 750 mm of well-distributed rainfall per year or with supplementary irrigation (600mm and 2500mm being the outer limits). Irrigation is essential right after planting unless this is done during the rainy season. After establishment, irrigation is only necessary when long dry periods occur. Overhead or drip irrigation is recommended and flood irrigation should be avoided. Pineapples cannot stand waterlogging.
In Kenya pineapples grow well from sea level up to 2000 m. Altitude has an important effect on the flavour of the fruit; above 1800 m they become increasingly sour and acidic.
The best soil for pineapple culture is a well-drained, sandy loam with a high content of organic matter and it should be friable for a depth of at least 60 cm. The crop does well on optimum pH of 4-5. Soils with old ant hills have a higher pH, and are not suitable for the production of good pineapples. Avoid black cotton soil, low lying areas and common red loams that are likely to flood.
In areas where the soils have high clay content, it is essential to plough also during the dry season to facilitate root penetration of pineapples. Plough to a depth of 45 cm, or if using hand digging, dig as deep as possible. After ploughing, use a disc harrow to produce a fine tilth.
Small-scale growers can uproot old pineapple plants by hand, while large growers can use a large harrow to uproot and chop the stumps and leaves.
If legumes are used as green cover plants, it should be considered that they supply significant amounts of nitrogen to the soil when calculating the amounts of compost required. In this case, compost with a rather high C/N ratio should be used. If possible, the compost should be spread in two separate lots: one half (about 2.5 tons) before planting, and about 2.5 tons to induce flower formation. Organic foliar feed is also beneficial. However too much nitrogen will result in watery/ glassy fruit as well as in production of multiple crowns on fruits and too many slips. Deficits in the potassium supply can be balanced out by the use of wood ash (combined with compost). In exceptional cases, the certification bodies will allow the use of potassium magnesia in organic farming.
No fertilisation should take place after the first bud stage.
Crop rotation is important to avoid build-up of root knot and other nematodes that contribute to large crop losses. To be effective, crops known to reduce or eliminate root knot nematode infestation should be planted between pineapple crops. (See also biofumigation ). For more information on root-knot nematodes click here
- Crowns are the leafy growth on top of the fruit. In Thika these take 25-28 months to come into bearing, but have uniform growth and are less susceptible to premature fruiting.
- Slips are leafy shoot growth arising from the fruit stalks. They take 22-24 monts to come into bearing.
- Suckers are leafy shoot growth from the base of the plant where the roots grow. They give the highest yield, but take long to fruit production. They are also more difficult to plant. Suckers take 18-22 months to come into bearing.
To achieve uniform plant growth, selection and sizing of planting material is of major importance.
All planting material can be stored upside down (to promote suberisation and avoid rotting) in the shade for up to three months and then planted in loose friable dry or preirrigated soil. Only totally healthy and if possible large shoots should be chosen (about 400 to 500 g in weight are best), in order to ensure a uniform crop.
Slips can also tolerate dryness, yet not as well as the suckers as they are generally lighter in weight. Slips vary much in size making grading in sizes necessary in order to have uniform plantings.
Rapid multiplication
If there is shortage of planting material, each type of planting material can be split vertically into 2 or 4 sections with a bit of root section, suberised and planted into irrigated nurseries at very close spacing. They can then produce new plantlets in 3 to 4 months time.
To avoid infection by dry-rot fungus all of the shoots should be stored in a shady place for wounds to heal and suberise quickly. Take care that no mealybugs are present in the shoots or on the leaf blades.
No soil should remain on the shoots to prevent infection by soil-borne fungi such as e.g. Phytophthoraspp. and/or nematodes. Hot water treatment (50°C for 30 minutes to two hours) of planting material is efficient and can control both mealybugs, Phytophthora and nematodes. After this treatment it is important to drip-dry the planting material to avoid fungal attack and deterioration.
Planting is normally done at the beginning of the long rains.
In intercropping the same double rows can be used and interplanted with legumes and/or cereals. The intercropped area and the pineapple area can then switch location when pineapples need replanting. Intercropped legumes help provide nitrogen to the pineapple crop.
(From "Fruits and Vegetables Technical Handbook")
Fruits can then be cool-stored for up to four weeks (storage temperature about 7°C). Because of their low sugar-content, pineapples harvested too early are unpopular amongst consumers (unripe pineapples do not ripen after harvest). The colour of the skin is an important criterion in determining the ripeness of the fruit. Fruits destined for the European market are often classified according to the extent to which an orange-yellow colouring has spread up from the base of the fruit as follows:
- Ripeness-colour 1: Only the base is orange-yellow.
- Ripeness-colour 2: The orange- yellow colour covers half of the fruit.
- Ripeness-colour 3: The orange- yellow colour reaches three quarter up.
- Ripeness-colour 4: Whole of the fruit yellow.
Every care should be taken to prevent bruising. Pineapples should not be thrown into lorries as this will cause bruising.
For canning the sugar/acid ratio (°Brix) is measured and the fruit is graded according to sizes. 13 to 16° Brix is suitable for canning. This is only attainable when the fruits mature when there is plenty of sunshine.The graded sizes are based on the diameter of the fruit as follows:
- Grade I - 12.7 cm minimum diameter and 15.3 cm minimum length (about 3 ½ kg fruit)
- Grade II - 10.8cm minimum diameter and 13.3 cm minimum length (2 ½ - 3 kg fruit)
- Grade III: 8.9 cm minimum diameter and 11.4 cm minimum length (1 ½ - 2 kg fruit)
Pruning
Once the fruit has been harvested, remove all slips and leave generally only 1 (maximum 2) strong and healthy sucker arising from ground level. Leaving more suckers will reduce the size of harvested fruits. The rest of the slips and suckers can be used as additional planting material after sorting or can be chopped and used as mulch. The mother plant can be left in the field as mulch.
Ratoon crop. The yields of ratoon crops are much lower than of the planted crop, so generally only one ratoon crop is economical. A second and third ratoon crop are possible under small scale conditions where the crop is interplanted with other crops, and fertilised well, provided there is no mealybug infestation. Once this has been harvested, all plants need to be dug up and the land prepared for rotation crops.
Planting methods and cultivation systems in organic farming:
In the majority of organic plantations, pineapples are planted together with other crops either in agroforestry or mixed crop systems. Examples exist where pineapples are planted as a rotation-fruit with green fallow land and other crops. The farm plan will depend upon which cultivation form is adopted (agroforestry system, mixed crops as a bottom culture, crop-rotation etc.).
Pineapples are an excellent choice to plant for a limited time on young agroforestry systems. Pineapples as well as papaya are well suited as so-called "nursery crops" to raise trees. Yet, they are less demanding regarding soil fertility. Pineapple plants require a lot of light; they will not produce saleable fruit if grown in the shade. Therefore, they should be planted away from the canopy of trees in an agroforestry system. Pineapples planted in diverse agroforestry systems will usually have no need to be supplied with external, organic fertiliser. The less varieties an agroforestry system contains (especially when leguminous trees are lacking), the more the soil will need to be fertilised with compost (or an undergrowth of soil-covering legumes).
Pineapples are easy to combine with other crops as a bottom crop. In particular: coffee, cocoa, coconut, cashew, coconut and date palms, avocado and mango. In diverse agroforestry systems, crop rotation is unnecessary. However, if pineapples are planted as bottom crops in a mixed system, e.g. with oil or date palms, then the crop rotation methods mentioned above must be adhered to in order to avoid a build up of pests and a decline of the soil fertility.
As soon as the plantation begins to produce fruit, any harvested plants should be removed and cut up before being spread over the soil. The plantation will also need to be thinned out from time to time, because suckers, which continually develop, may limit the amount of room available for each individual plant.
Tilling weeds is neither possible nor desirable in agroforestry systems. When all possible niches are already occupied with plants, weeds will have little chance of gaining a foothold, and can also easily be uprooted by hand. Mature weeds can be cut down with a knife or pulled out and then cut up to be used for mulch material. One preventative measure is to sow non-climbing legumes before the pineapples are planted (e.g. Pueraria ssp, but Purearia phaseoloides develops strong tendrils, and is not suitable for pineapples. Some Vigna ssp. among others) can be used. Usually, this bottom culture will suppress the growth of weeds. Depending upon the amount of water available, when enough weeds have accumulated, these can be cut down and used as mulching material.
|
Mealybug or pineapple wilt virus Infected plants become yellowish-red to bright red at the leaf tips, this colouration spreading down the leaf with time. Soon other leaves turn colour and also show signs of wilting. However, the inner heartleaves remain normal. Severely infected plants become stunted and produce small, undergrade and immature fruits. The first effect of the disease usually appears in the roots, which stop growing, collapse and then rot; this results in leaves symptoms similar to the effect of drought. The root system collapses and rots before the first leaf symptoms appear. |
Mealybugs
Female mealybugs on passionfruit leaf. Female mealybugs are 3 to 5 mm long and their body is usually covered with a waxy secretion. © A.M. Varela, icipe |
|
What to do:
|
|
Yellow spot virus The yellow spot virus has been shown to be identical to the tomato spotted wilt virus. It infects over a 100 species of plants including peppers, tomato, tobacco, eggplant, potato, broad bean, spinach, chicory and peas. A number of wild plants, including some common weeds such as the black jack (Bidens pilosa), Emilia sonchifolia and Datura stramonium, are also host of this virus. |
|
|
What to do:
|
- ARC-Institute for Tropical and Subtropical Crops (2000). Cultivation of pineapples. www.nda.agric.za. Also available from the National Department of Agriculture at: www.nda.agric.za/publications ISBN 1-86871-072-6
- Acland, J.D. (1980). East African Crops. An introduction to the production of field and plantation crops in Kenya, Tanzania and Uganda. FAO/Longman. ISBN: 0 582 60301 3
- Agricultural Information Centre, Nairobi (2003). Fruits and Vegetables Technical Handbook
- CAB International (2005). Crop Protection Compendium, 2005 edition. Wallingford, UK www.cabi.org
- Common Names of Diseases, The American Phytopathological Society.Retrieved from www.en.wikipedia.org
- FICCI Agribusiness Information Centre India
- Food Market Exchange (2002-2003). www.foodmarketexchange.com
- Morton, J. (1987). Pineapple. p. 18?28. In: Fruits of warm climates. Julia F. Morton, Miami, FL. www.hort.purdue.edu
- Naturland e.V. www.naturland.de (2001). Organic farming in the Tropics and Subtropics. Pineapples. www.naturland.de
- Nutrition Data www.nutritiondata.com.
- Personal interview with Dr. S. Nganga, former Head Superintendent, Founder of Research and Development at DelMonte, Kenya.
- Petty, G. J. (1994). The pineapple mealybug. Institute for Tropical and Subtropical Crops, Nelspruit. H. 15/1994.
- Ullman, D. E., Williams, D. F., Fleisch, H., Hu, J. S., Sether, D., Gonsalves, A. (1993). Heat treatment of pineapple: subsequent growth and occurrence of mealybug wilt of pineapple. Acta Horticulturae, 334:407-410.
