Paw Paw/Papaya

24.05.17

Papaya (Carica papaya), also called papaw or pawpaw in Australia, is an exotic, tropical fruit with a juicy, sweet flavour. Papaya and pawpaw are the same species, however they look and taste different. In Australia, the red-fleshed sweeter fruit is called papaya, while the yellow-fleshed fruit is called pawpaw. From an Australian industry perspective however, the term papaya covers both fruit.

While predominately grown for the fresh fruit market, papaya is also used in beauty products and topical treatments for skin conditions, however, some people can have allergic reactions to papaya due to its latex content.

Overview

Papaya originated in the tropics of the Americas, but is now widely cultivated around the world, particularly in the tropical climates of Asia, Africa and Polynesia. It is understood to have arrived in Australia around 1875, when a British physician discovered its medicinal properties and started using papaya to treat patients in a Brisbane hospital. The papaya industry in Australia is centred in the tropics, mostly around Innisfail and Mareeba in northern Queensland.

Papayas grow as single-stemmed trees with a crown of large leaves emerging from the highest part of the trunk. They normally live for about 5–10 years, although in commercial plantations they tend to be replanted every 3–4 years, or when they are too tall for easy harvesting.

The size and shape of the papaya fruit depends on the variety, but most are round, pear-shaped or oval, measuring 10–50cm and can weigh from 200g to more than 3kg. The firm flesh is either yellow or orange (red) with an abundance of tart and edible black seeds contained within the central cavity of the fruit.

Papaya production is labour intensive as fruit is produced year round and harvested weekly. However, it is a relatively easy industry to enter as the capital expenditure is not high and the first fruit is ready for harvest in less than a year. Because trees are replaced every few years, growers have some flexibility in entering and leaving the industry, depending on the economics of production.

Many papaya trees in Queensland were destroyed during Cyclone Larry in 2006 and to a lesser extent, during Cyclone Yasi in 2011. However, with government support the industry has developed a strategic plan that aims to develop the industry beyond its previous production levels. The peak body for papaya growers in Australia is Papaya Australia Ltd.

Facts and figures

  • Papaya is an exotic tropical fruit that is mostly eaten fresh, but may be used in juices, nectars, purees, jams, jelly or as dried fruit
  • Pawpaw (papaw) and Papaya are the same species but two very different fruit. Papaya has red flesh, while pawpaw is yellow, however in Australia the term papaya refers to both fruit
  • The industry is relatively easy to enter due to low capital outlay and quick financial returns compared with other fruit or tree crops
  • First harvest can take place nine months after planting and then the crop is harvested continually (weekly or twice a week) for the next two years
  • The industry is susceptible to opportunistic growth and oversupply
  • The fruit is extremely fragile and transporting it to markets can be a challenge.

Production status

In 2006, Cyclone Larry devastated the industry, with a total loss of between 65% and 95% of fruit-bearing trees. Since then, government support and an Australian Industry Strategic Plan have been implemented to ensure the industry recovers and exceeds former production levels in the future.

While Australian papaya production is very small compared with other countries and very small quantities of Australia’s papayas are exported. Almost all of the imports were from Fiji, with a small amount from Thailand.

Australia’s papayas are grown mainly in the tropical regions of Innisfail and Mareeba in northern Queensland. Small amounts are also grown in the Northern Territory, southern Queensland, the Kimberly and Carnarvon regions of Western Australia, and northern New South Wales.

Map of current and potential growing regions

Uses

Papaya is an exotic tropical fruit, which is mostly eaten fresh or used in juices, nectars, purees, jams, jelly or dried fruit.

Green papaya is an ingredient in Asian-style salads but is also served as a cooked vegetable or preserved in chutneys.

Pawpaw is a common ingredient in beauty products and topical creams for skin conditions.

Production Requirements

Growing regions

Papaya is grown predominately in the tropical climate of north Queensland, in areas around Innisfail, Mareeba, Proserpine, Yarwun and Gympie, and in the subtropical climate of the Sunshine Coast. Small amounts are grown in the Northern Territory, the Kimberley and Carnarvon regions of Western Australia, and northern New South Wales.

The industry has expanded into the Tablelands/Dimbulah region of Queensland and there has been some growth in the Innisfail coastal region where banana and sugar cane growers have moved into papaya.

Soil type

Apart from heavy clay soils, most soil types are suitable for papaya production. The main factor when considering soil characteristics is to ensure good drainage, which is crucial to minimise tree loss from root rot. Therefore sites that are prone to seepage or waterlogging should be avoided.

A topsoil depth of 1m will support optimum growth and fruit production while a minimum depth of 0.5m is essential to avoid waterlogging. Mounding soil prior to planting may be necessary in higher rainfall areas to increase drainage from the root zone.

Climate

Papaya is a tropical plant that grows best in a warmer climates. Optimal production takes place in regions with a minimum monthly rainfall of about 100mm, minimum relative humidity of 66% and where temperatures range between 21°C and 33°C.

Papaya is susceptible to frost damage, which can kill the plant, and cool winter temperatures (below 12–14°C) will limit growth and fruit production. However, papaya has also been grown successfully in warm, frost-free locations in coastal south east Queensland.

Papaya is susceptible to wind damage, which can reduce growth and fruit set, damage leaves and blemish fruit, therefore windbreaks are recommended if the site is subject to strong prevailing winds.

Varieties

There are around ten varieties of papaya grown in Australia.

Hawaiian Solo Red is the most popular red variety and the most commonly grown variety in the world. It is much sweeter and has a better flavour than yellow pawpaw.

The yellow hybrid varieties, Hybrid 1B and Hybrid 13, and the red-fleshed Hybrid RB1, Sunrise Solo, Linda Solo and Sunset Solo are the most popular papaya varieties grown in north Queensland.

Advice on the right variety can be sought from specialist nurseries or local exotic tropical fruit industry development officers.

The industry is investing in plant breeding to breed new varieties that raise the eating quality for consumers and reduce skin blemishes.

Planting and crop management

Papayas are normally grown in rows in plantations (orchards) with the rows running with slope of the land. This helps to minimise erosion, provide adequate drainage and allow efficient machinery access through the trees.

Rows should be deep ripped with a grader or alternative machinery to a depth of at least 60cm, about 4m apart. About 1.5–1.8m should be planned between trees within the rows. In order to prevent root rot caused by waterlogging, rows should be mounded so they are 1.5m wide at the base.

The plantation should be sheltered from strong winds for optimum yield and fruit quality. Not only can strong winds knock over and defoliate trees, wind can reduce the activity of insect pollinators and also dry out the reproductive parts of flowers, affecting pollination success rates. Windbreaks are essential where plantations are exposed to major damaging winds.

A soil analysis at orchard establishment is often recommended to understand which nutrients, if any, need to be added to the soil prior to planting. Papaya should be planted early in the dry season and the soil kept moist until plants are well established – sometimes watering twice a day may be necessary.

Papaya growers can establish their orchards from trees, seedlings or seed.

Papaya trees are available from specialist horticultural nurseries and it is recommended to plant one male plant per ten female plants. There are cross-pollinating varieties (separate male and female plants) and self-pollinating varieties (“bisexual” plants with male and female parts on the same flower) grown commercially in Australia. Cross-pollinating varieties are generally recommended because they have higher fruit yields and relatively predictable, and therefore marketable, fruit shape.

Growers may produce seedlings from their own seed or seed ordered from a specialist nursery. Seeds should germinate between 14 and 26 days and can be transplanted at around 10 weeks.

Seedlings are available for purchase from specialist horticultural nurseries. The seedlings should be disease-free, sturdy and 150–200mm tall with dark green foliage. In south east Queensland, seedlings are best planted in February and March. In central Queensland and the Atherton Tablelands, seedlings are best planted between March and May and in October. Mulching after planting with organic mulches to a depth of 10–15cm is recommended to maintain soil moisture, reduce weed growth and reduce soil erosion. Suitable organic mulches include forage sorghum, hay, wheat or barley straw, grass or lucerne hay.

The sex of trees cannot be determined before they flower. Therefore several seedlings should be planted at each tree site to ensure an optimum ratio of sex types. Once the tree’s sex can be determined, based on the nature of the flowers and their stalks, the plantation should be thinned, with the aim of achieving a ratio of one male plant per ten female plants. Unwanted trees are cut off close to ground level. Suckers on male trees and side shoots below the flowers on female trees will require pruning.

Although papaya is grown in high rainfall areas, requiring about 100mm of rainfall per month, additional irrigation (50–160 litres per tree per week) is essential to maintain tree health and fruit production. Papayas can be damaged by saline water so always check water quality before irrigating plants.

The Queensland Department of Agriculture, Forestry and Fisheries website provides information about irrigation and fertiliser practices to grow papaya.

Pollen transfer from male to female flowers is essential for papaya fruit to develop. A combination of wind and insect pollination is needed to pollinate trees, with the hawk moth being identified as the primary pollinator in Queensland orchards. AgriFutures Australia has developed a fact sheet for maximising Pollination management for papayas in Australia.

Trees should produce their first crop at 9–12 months and be productive for 2–3 years. As the tree gets taller its fruit quality and yield decreases and it becomes harder to harvest easily. At this stage, the economics of retaining the tree must be considered.

Weeds, pests, and diseases

The Queensland fruit fly (Bactrocera tryoni) and Mediterranean fruit fly (Ceratitis capitata) are significant threats to papaya production and fruit fly damage impacts export market access.

Queensland fruit fly is widespread throughout Queensland and has a limited distribution through south eastern Australia. The Mediterranean fruit fly is restricted to Western Australia. The National Fruit Fly Strategy has developed a website that includes seasonal advice and fruit fly control strategies.

The papaya ringspot virus (Potyvirus spp) is caused by planting diseased plants and can also be spread by aphids. The virus causes yellow patterns to develop on leaves and green ring-shaped markings appear on the skin of infected fruit. Trees may become stunted if infected when young and infection causes reduced fruit set, reduced vigour and impacts on fruit quality and taste. There is no cure for this disease.

Biosecurity Manual for the Australian Papaya Industry, which outlines ways in which growers can reduce the threat of pest and disease outbreaks on their properties, has been developed by Plant Health Australia.

Infrastructure Requirements

Most established horticultural enterprises in tropical Australia suit the production of exotic tropical fruit. Most papaya growers also grow a range of other crops, such as sugar cane, banana, mango, avocado, other tree fruits and vegetables. Many growers also raise cattle.

Apart from land and access to water, the infrastructure required to grow papaya includes:

  • tractor
  • slasher
  • 4WD tray back utility
  • separate sprayers for herbicides and pesticides
  • picking trailer, harvest-aids
  • packing/machinery/chemical sheds
  • dipping/spraying/washing equipment
  • cold room
  • ripening room
  • cultivation equipment
  • irrigation system
  • tensiometers or capacitance probes (for monitoring soil moisture)
  • picking poles
  • fertiliser spreader.

If contract services are available, not all equipment may need to be purchased.

The papaya crop is labour intensive and while two people should be able to undertake the maintenance required for a 1ha orchard, casual labour will most likely be needed to assist with harvesting.

Harvesting & Processing

Papaya is harvested all year round with production peaks during autumn and spring. It is a labour-intensive crop, requiring harvesting and packing at least once a week all year round. In north Queensland, harvesting and packing is required twice a week throughout most of the year.

Typically, harvesting begins 9–10 months after planting. Papaya is harvested by hand with access to the fruit gained by ladder or harvesting platforms. Eventually the trees become too tall to harvest easily and are replaced.

Papaya is a fragile fruit that is easily damaged, so needs careful handling to prevent bruising. It is packed in a single layer, in a cardboard or polystyrene carton. The fruit can be further protected from damage through the use of poly socks or paper wraps. The industry is investing in the development of postharvest technology and management of the supply chain aimed at extending storage life and retaining quality.

The best storage and transport conditions for green papaya are 13°C with a relative humidity of 90–95%. Ripe papaya is best stored at 10°C with a relative humidity of 90–95%. Papaya can be ripened using ethylene gas under controlled conditions in special ripening rooms.

In north Queensland, the average yield is between 5–6 cartons per tree.

Markets & Marketing

More than 95% of papayas are grown for the fresh market, with the remainder going to a minor processing industry. Most of the Queensland papaya crop is sold via the metropolitan wholesale markets in Brisbane, Sydney, Melbourne, Adelaide and Newcastle. Small amounts are exported and the remainder is sold locally.

Data relating to historical papaya production and prices is available in the RIRDC Report Emerging animal and plant industries: Their value to Australia.

Risks & Regulations

Risks/challenges

Papaya is a popular crop for new entrants to exotic tropical fruit production, as it provides a quicker financial return than most other tree crops, but there are a number of challenges. Papaya is susceptible to disease and rain can cause waterlogging, resulting in root rot and tree losses. Cyclones, floods and extended rain periods can cause significant or complete tree losses.

Papaya is a labour intensive crop that requires harvesting and packing at least once a week all year round. In north Queensland, harvesting and packing is required twice a week during most of the year.

The papaya is a fragile fruit that is easily damaged. Therefore, it needs careful handling to prevent skin blemishes and bruising. Even then, its fragility makes transporting it to markets a challenge.

The Australian papaya market is relatively small and can easily be oversupplied as new growers easily and quickly enter the market. There is a low level of consumer awareness of the fruit in Australia and the market size could increase, but this would depend on successful market development.

Regulatory considerations

The standard regulatory considerations that apply to all Australian farms, including laws applying to chemical use and management, occupational health and safety and transport (including machinery movements and the loading/unloading of harvested product), apply to papaya operations.

In addition there are a number of regulatory considerations specific to horticultural operations.

Before buying new land to plant orchards, a thorough investigation of the land’s suitability for a horticultural enterprise and its cropping or land use history, should be undertaken. This may include identifying a history of chemical contamination (and residue levels) as some export licences may be withheld on products grown on land where chemical residues exist. Potential disease risks should also be investigated. Some disease pathogens can survive in the soil for many years, so information about previous disease outbreaks will assist determining which trees are suitable for planting. This information can generally be obtained from the relevant state planning authority. Growers will also be responsible for regularly inspecting their orchards for notifiable pests and diseases and reporting any incidence to the relevant state agriculture department.

When planting new orchards and establishing additional on-farm infrastructure or access roads, liaison with the state government agencies responsible for planning, native vegetation laws and water licences will be necessary. Some land use applications will also need to be considered by the relevant local government authority.

Horticulture and food production businesses have strict requirements in relation to record keeping, registrations, and accreditations as well associated costs for e.g. quality assurance, food safety, safe use of chemicals, environmental performance and intellectual property. Websites like Freshcare may provide a starting point for understanding these requirements.

Image Gallery

Whole papaya with other tropical fruits

Papaya tree with fruit

A halved papaya (front) and a halved pawpaw (back)