Pineapple (Ananas comosus) is an herbaceous biennial or perennial plant in the family Bromeliaceae grown for its edible fruit. The pineapple plant has a short stout stem and a rosette of sword-shaped leaves with needle-like tips.
The leaves are waxy, have upturned spines on the margins and may be soild green or striped with red, white or cream. When the plant flowers, the stem begins to elongate and produces a flower head of small purple or red flowers, each with a pointed bract.
The stem continues to elongate and sets down a tuft of of short leaves called a ‘crown’. Individual fruits develop from the flowers and fuse to form one large cylindrical fruit topped by the crown.
This fruit, known as a pineapple, has a tough rind made up of hexagonal units and a fibrous, juicy flesh which may be yellow to white in color. Pineapple may reach 1.5–1.8 m (5–6 ft) in height and some varieties can grow for in excess of 20 years. Pineapple originates from the tropical regions of the Americas.
Mealybug is a common pest of pineapple found on the surface of the pineapple leaf as well as inside the enclosed blossom cups.
It is also a vector of wilt disease in pineapple. Mealy bug can be controlled by spraying insecticide in the morning or evening on the pineapple field.
Nematodes are also serious pests of pineapple; They are controlled by fumigating the soil with 1, 3-D.
Root rot disease can be prevented by avoiding too much water around the root zone of pineapple but can be controlled by improving soil drainage.
- Symphilids: Symphilids are small centipedes that feed on roots. Plants suffer from nutrition deficiency, their development is reduced. As symphilids are not present uniformly in the soil, it creates “pockets” of plants attacked by symphilids in the middle of healthy plants.
- Mealybug: Mealybugs usually inhabit the axils of the leaves, the basis of suckers, the aerial roots, and the basis of the fruits. They transmit diseases and are associated with the devastating disease, pineapple mealybug wilt. Mealybugs feed on the pineapple plant sap which has an impact on the size of the pineapple fruit and produces chlorotic areas.
- Mealybug Wilt:Wilt is a virus partly transmitted by mealybugs. It affects the root system causing leaves to turn deep pink, yellowing and wilting. As a result of this, fruits may fail to develop or remain small, fibrous and sour.
- Heart rot: Heart rot enters through the heart of the plant and causes death in contaminated plants.
- Black rot: Black rot enters through the peduncle and injuries in the skin of the pineapple.
- Black spot: Black spot infection starts from one fruitlet (floral cavity) of the fruits. Infected fruits are not suitable for exports as black spots develop in the fruits. Infected fruits are not suitable for exports as black spots develop in the fruits. These symptoms appear 5-6 days after the harvest.
These nematodes invade the tips of primary roots and stop them from elongating. Plant roots infected with nematodes often become more susceptible to other diseases. In addition, affected plants are often stunted. The plants infested with nematodes present the same symptoms as when suffering from nutrients deficiency and drought.
Read Also: Amazing Health Benefits of Pineapple Peels
Meanhwile according to research, other pests and diseases of pineapple include the following below:
Common Pests and Diseases
Category : Bacterial
Bacterial heart rot and fruit collapse Erwinia chrysanthemi
Water-soaked lesions on the white basal sections of leaves in the central whorl which may spread to all leaves in the central whorl; midportions of leaves become olive green in color with a bloated appearance; infected fruits exude juices and the shell becomes olive green; cavities form within the fruit
Disease is thought to be spread from the juices of infected fruits; bacteria in the juice can enter leaves through wounds; ants acts as vectors for the bacteria
Remove and destroy infected fruits; avoid the use of infected crowns for seed material to prevent spread of the disease; planting to avoid flowering when adjacent field is fruiting can reduce disease development; use of miticides and control of ants can significantly reduce disease incidence
Category : Fungal
Butt rot, Black rot & White leaf spot Chalara paradoxa
Soft black rot which begins at the area where the seed piece detaches from the mother plant; entire seed piece may be rotted; black rot of fruit causes a soft, watery rot which darkens with time; small brown, wet spots develop on leaves; leaf spots enlarge and turn gray-brown with light brown margins
Fungus survives in soil and pineapple residue; infects plants through fresh wounds
Seed material should be stored on mother plants during dry weather and with good air circulation; freshly removed seed material should be dipped in an appropriate fungicide within 12 hours of removal from the mother plant; avoiding bruising and wounding of fruit during harvest helps to reduce black rot; harvested fruit should be dipped in an appropriate fungicide within 6-12 hours of harvest to prevent disease development during shipping
Read Also: Methods of Weed Control in a Pineapple Farm
Category : Other
Marbling Acetobacter spp.
Yellow to red or very dark brown discoloration of fruit flesh; infected tissues develop a granular texture with woody consistency and speckled color; single or multiple fruitlets may be affected; vascular system may appear speckled right down to core of fruit; symptoms develop during the last month of fruit maturation
Emergence of the disease is favored by warm, wet weather
There are currently no methods of controlling the disease; the pineapple variety Smooth Cayenne appears to be moderately resistant to the disease
Category : Viral
Mealybug wilt Pineapple wilt virus (PWV)
Leaves turning red; tips of leaves become withered and turn brown; plants can be easily removed from the soil
Virus is transmitted by mealybugs; ants protect mealybug populations from predators and parasites and can allow mealybugs populations to reach very damaging levels if left uncontrolled
Ants should be controlled with an appropriate insecticide
Category : Oomycete
Phytophthora heart and root rot Phytophthora spp.
Symptoms of Phytophthora root rot in pineapple field
Symptoms of Phytophthora root rot in pineapple field
Phytophthora symptoms on pineapple
Pineapple heart rot
Phytophthora symptoms on pineapple fruit
Young leaves failing to elongate and turning chlorotic; heart leaves wilting and turning brown; terminal whorl can be easily pulled from mother plant; water-soaked tissue at base of leaves; foul smell; leaves may be turning red and yellow with necrotic leaf margins and leaf tips; plants can easily be pulled out of the ground; fruits color prematurely
Fungi can survive in soil and plant debris for many years
Planting in raised beds helps to drain the soil and reduces incidence of the disease; mulch from pineapple debris should be avoided; pre-planting dips and foliar applications of Fosetyl Al are very effective at controlling the disease.
Category : Insects
Mealybugs (Pineapple mealybug) Dysmicoccus brevipes
Flattened oval to round disc-like insect covered in waxy substance on tree branches; insects attract ants which may also be present; insect colony may also be associated with growth of sooty mold due to fungal colonization of sugary honeydew excreted by the insect; plants may show symptoms of mealybug wilt (see entry)
Insects have a wide host range; often tended by ants which farm them for their sugary honeydew secretions; transmit mealybug wilt in pineapple
Mealybugs can potentially be controlled by natural enemies such as lady beetles; ant populations which tend the mealybugs should be treated with an appropriate insecticide.