Postharvest Diseases Tropical Fruits

Postharvest diseases – tropical fruits 1

Postharvest diseases – tropical fruits


Some important tropical fruits

• Avocados• Bananas• Mangoes• Papayas• Pineapples


Fruit ripening

• Non climacteric fruits– have a respiration rate which at a given

temperature remains roughly constant during the postharvest period

– are not capable of significant changes after harvest because they have no starch reserves

– must be allowed to remain on the plant until they have attained satisfactory eating quality

– examples: citrus, grapes, cherries, pineapple


• Climacteric fruits– characterised by a sudden surge in respiration

rate, usually after harvest, known as the climacteric rise

– climacteric rise is triggered by ethylene (produced in small quantities by the fruits themselves)

– over a period of several days, starch is converted to sugar, skin colour changes and flavour and aroma develop

– the usual aim is to harvest just before the climacteric


Avocados (Persea americana Miller)

• Originates in South America• subtropical, semitropical and tropical types• Leading producers are Mexico, USA, Brazil,

Dominican Republic, Indonesia, Haiti, Peru, Israel, Venezuela, Colombia

• Climacteric fruit but ripening is possible only after detachment from the plant

• If picked immature, avocados do not have the capacity to ripen normally after harvest


avocado


Avocado – important diseases (1)• Anthracnose/black spot

– caused by Glomerella cingulata (asexual stage is Colletotrichum gloeosporioides)

– important disease in most avocado-growing countries

– initial infection may occur at any time during the growing season

– anthracnose mostly remains quiescent; fungus effects complete penetration of the skin only after ripening

– Control: orchard fungicide sprays; postharvest fungicide treatments; storage in controlled atmosphere


avocado anthracnose


Glomerella cingulata - distribution


Avocado – important diseases (2)

• Stem end rots– causal agents: Lasiodiplodia (Botriodiplodia)

theobromae, Phomopsis perseae, Dothiorella spp.

– infections can occur in the field (latent infections) or at the time of harvest

– control: orchard spraying with a range of fungicides can give partial control; harvesting fruits with longer stalks; postharvest fungicide dip; careful handling and rapid cooling


Lasiodiplodia theobromae - distribution


Bananas (Musa spp.) • originating in South East Asia• dessert bananas, plantains and cooking bananas• major producing countries

– Bananas: Brazil, India, the Philippines, Ecuador, Indonesia, Thailand, Mexico, Vietnam, Colombia and Honduras

– Plantains and cooking bananas: East and West Africa; major producer is Uganda

• Climacteric pattern of respiration• Fruit intended for local consumption can be cut

mature; fruit for distant markets must be cut immature and shipped green


banana


Bananas – important diseases (1)

• Antracnose– caused by Colletotrichum musae– known in all producing countries– preharvest infections and infections following

physical injury– Control: strict sanitation in plantation and

packhouse; fruits must be harvested at correct stag of maturity and handled carefully; postharvest treatment with systemic fungicide; cooling as soon as possible after harvest


anthracnose on banana


Colletotrichum musae - distribution

http://www.cabicompendium.org/cpc/map.asp?CCODE=COLLMU


Bananas – important diseases (2)• Crown rot

– caused by Lasiodiplodia theobromae (= Botryodiplodia theobromae), Ceratocystis paradoxa, Colletotrichum musae, Fusarium pallidoroseum, Verticillium theobromae

– disease complex; different organisms predominate according to location and time of year

– many of the causal fungi survive on leaf debris in the plantation; after cutting, the newly exposed tissue is vulnerable to infection


crown rot on banana Verticillium on banana


Verticillium theobromae


Bananas – important diseases (3)– Control: regular removal of leaves in plantation;

hygiene in packing station; dehanding with sharp knife; postharvest fungicide application with systemic fungicides; field packing of bananas

• Sigatoka disease– Caused by Mycosphaerella musicola and

Mycosphaerella fijiensis– Most serious banana disease; present in all

tropical banana growing regions– fungus is not present in the fruit, but has

profound effects on fruit development– Control: cultural and chemical methods


Mycosphaerella fijiensis - distribution


Mangoes (Mangifera indica L.)

• originates in the Malay peninsula• major producing countries: India, Mexico,

Pakistan, Brazil, Indonesia, China, Haiti, the Philippines, Madagascar, Tanzania

• Climacteric pattern of respiration• Mangoes for storage or export should be

harvested at the mature-green stage


mango


Mangoes – important diseases (1)

• Antracnose– caused by Glomerella cingulata– occurs in all mango-growing areas– symptoms typically appear as the fruit ripens– infection occurs in the field and typically

remaiins quiescent until the onset of ripening– Control: by pre- and postharvest measures;

frequent orchard spraying; postharvest immersion in hot water with fungicide; irradiation


Mango anthracnose


Mangoes – important diseases (2)• Black (mould) rot

– caused by Aspergillus niger– of particular importance in India– fungus persists in soil on decaying vegetation;

fruits on the tree may be reduced to dried-up mummies; most infections occur during and after harvest when the fungus penetrates wounds or the cut stem

– Control: orchard sprays; postharvest treatments with hot water containing fungicide; careful handling to prevent mechanical damage


Mangoes – important diseases (3)• Stem-end rots

– caused by Lasiodiplodia theobromae, Phomopsis, Dothiorella, Colletotrichum gloeosporioides

– occurs in most mango producing areas– fungi persist in the orchard by colonizing dead

wood; infection usually occurs at or shortly after harvest when the cut stem is invaded

– Control: prompt and careful handling; attention to hygiene; application of fungicidal paste to the cut stem; postharvest dip in hot bath with fungicide


Papayas (Carica papaya L.)

• originates in Central America• major producing countries: Brazil, Mexico,

Indonesia, India, Congo, the Philippines, China, Peru, Colombia, Mozambique

• climacteric fruits• must be harvested mature-green for long

distance transport


papaya


Papayas – important diseases (1)

• Antracnose– caused by Glomerella cingulata– important disease in most papaya-growing

countries– infection occurs in the field but symptoms only

appear as the fruit ripens (quiescent infections)– Control: orchard hygiene; fallen leaves and

fruits should be collected and destroyed; orchard fungicide sprays; postharvest hot water treatment or fungicidal wax application


papaya anthracnose



• Phytophthora rot– caused by Phytophthora palmivora– important in Hawaii, East Africa, India, Taiwan– fungus persists in the soil; infection occurs in

the field; recent infections may be undetectable at time of harvest

– Control: use virgin soil for new plantings; orchard fungicide sprays; postharvest hot water treatment


Phytophthora palmivora on papaya


Phytophthora palmivora - distribution



• Stem end rots– caused by Mycosphaerella caricae (asexual

stage: Phoma caricae-papayae), Phomopsis, Phytophthora spp., Botryodiplodia theobromae

– the newly cut stem-end is exposed to contamination during and shortly after harvest

– Control: orchard fungicide spray; fruit harvesting with part of the stem; immersion in hot water bath


black stem end rot


Phoma caricae-papaya - distribution


Phytopthora stem end rot


Pineapples (Ananas comosus L.(Merr.))

• originating in South America• major producers: Philippines, Thailand,

Brazil, India, USA, Vietnam, Indonesia, China, Mexico, Ivory Coast

• pineapple is non-climacteric; it must be allowed to develop most of its eating qualities whilst still attached


pineapple


Pineapple – important diseases (1)• black rot (soft rot/stem-end rot/water rot)

– caused by Ceratocystis paradoxa (asexual stage: Thielaviopsis paradoxa)

– occurs in all major producing countries; causes serious losses

– fungus survives on plant debris in the soil as chlamydospores

– infection may occur before harvest via insect punctures or growth cracks or via the natural crevices between individual fruitlets; more usually infection occurs through the cut stem or through wounds during handling


black rot on pineapple


Ceratocystis paradoxa - distribution


Pineapple – important diseases (2)• Fruitlet core rot (brown rot/black rot/eye

rot/black spot)– caused by Gibberella fujikuroi var. subglutinans

(asexual stage: Fusarium moniliforme var. subglutinans), Penicillium funiculosum, Pseudomonas ananas

– occurs in most producing countries– causal organisms survive on debris in soil and

are spread by water and insects; mites and mealybugs which damage the tissue can facilitate infection


Pineapple – important diseases (3)

– infection can occur at any stage of fruit development

– Control: mites and mealybugs should be controlled


Fusarium moniliforme var. subglutinans - distribution

Postharvest Diseases Tropical Fruits

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