Propagation
Pineapples are propagated vegetatively by planting crown, slips or suckers. The propagules are extremely resistant to desiccation and root readily when planted in the nursery or in the field. By planting various types or propagules the period of harvest can be extended since offshoots (suckers) fruit in about 17 months, slips in 20 months and crowns in 22-24 months.
Planting takes place at the start of the rainy season or it ca start any time in the irrigated areas. Scaly leaves should be removed from the lower 3cm of the propagule stem to expose future roots. The propagules should be allowed to air dry for one week prior to planting so that the callus layer is formed over the damaged tissue.
Spacing: 2ft x 1ft x 4ft or 60cm x 30cm x 120cm.
The propagules can be ridges or on a level grand. Ridge planting helps to create water harvesting trenches for harvesting water between the double two spaces.
Cultivars: Smonth Cayene is by far the most important pineapple cultivar throughout the topics, the leaves are almost spineless and larger fruits of high quality are produced. Queen is still grown in some areas. This cultivar produces smaller but fruits than smooth cayenne, but the leaves are spiny and unpleasant to work with. The red Spanish is a semi spineless cultivar grown mainly in West Africa and South Africa. Its fruits are intermediate between those of smooth cayane and queen but are of better quality than those South Cayane. It has some resistance in mealybug wilt disease.
Environment and soils
Low and medium elevation in tropical areas are much more preferable. Well drained and alkaline soils are also preferred, pH, 5.0-6.5
Fertilizers: Nitrogen is the nutrient most used by pineapples. It can be applied at the rate of 50kg per hectare top dressed one month after planting. Additional 40-670 kg per hectare applied three to six months interval is recommended before maturity. An additional 200 kg per hectare of nitrogen can be applied to each ratoon crop. Where phosphorus is lacking, plants have narrow brittle leaves with a dark red color spreading the entire leaf.
Potassium deficiency produces a poor quality fruit; few suckers and slips will be formed. The best method of application is preplant broad cast mixed with the top 15 cm of soil. Iron deficiency is identified by a general chlorosis similar to that typical of nitrogen deficiency Zinc deficiency causes a mottled yellowing of the leaves.
Pests
Weeds are the primary pests affecting pineapple production, to obtain maximum production, perennial weeds should be dug out prior to planting and all newly germinating weeds should be controlled while in seedling stage. A mulch of leaves, grass or other organic materials such as chopped debris from previous pineapple crops is beneficial in restricting weed growth, decreasing erosion adding humus to the soil and conserving moisture. Selective herbicides are available which provide effective weed control.
Nematodes, particularly the root knot nematode may become a problem and is a serious pest in many pineapple growing regions. Infestations by pineapple mealy bug result in yellow spots appearing on the leaves but, more importantly the insects spread black spot (penicilium funiculosum and fusarium moniliforme), and are also responsible for mealy bug.
Control: Dipping pineapples before planting in a fungicide-insecticide solution can help to eliminate them.
Thrip may be important as vectors of yellow spot virus which causes deformed fruits or the production of fruits with several dead fruitlets. Hosts of the virus other than pineapple are weeds such as black jack, datura stramonium, emila sonchfolia and vegetables such as pepper, tomoto egg plant broadbean, spinach and peas. Yellow spot of pineapples is usually more severe when these plants are grown nearby.
Hear and root rots caused by the fungus phytophthora cinnamoni and p. parasitica are sometimes serious. Pink disease, caused by a bacterium transmitted to ripe fruits by insects causes a browning of canned fruits but can be prevented by early harvesting. The disease enters fruits via wounds and causes the fruit to ferment, producing a yeasty, alcoholic smell and undesirable off-flavor.
Control is by careful handing to prevent injury and by sorting so that injured fruits are consumed or processed rapidly and only uninjured fruits are sent to the market.
