Growing papaya
Common questions
Patricia Chay et al ., Department of Primary Industries and Fisheries.
This information has been extracted from the Agrilink Papaya Information Kit, which provides information on all aspects for growing and marketing papaya in Queensland.
Introduction
This section contains the most commonly asked questions about growing papaya in Queensland. The answers are as brief as possible. Where this is difficult and more detail is required, we refer you to other sections of the Agrilink Papaya Information Kit.
Varieties
What type of papaya do people buy?
The market for papaya is divided into different segments, based on fruit characteristics and how it will be eaten. There are yellow-fleshed papaya and red-fleshed papaya, small and large papaya, and both can be eaten either as fresh fruit or used as a vegetable. Once you decide which market segment you want to supply, then you can decide on the varieties to plant.
What variety should I grow?
Most papayas grown in Queensland are hybrid varieties or inbred lines. The variety you choose depends on whether you are in north, central or south Queensland. You should also consider what type of fruit your market agent prefers.
The more established yellow-fleshed hybrid varieties, Hybrid 1B and Hybrid 11B, and the red-fleshed Hawaiian Sunrise Solo, are popular commercial papaya varieties for north Queensland.
The yellow-fleshed hybrids Hybrid 29 and Hybrid 14 have performed well in the Yarwun area of central Queensland.
South-east Queensland growers have traditionally grown the yellow-fleshed PG and Richter Gold lines. Other recent but relatively untested red-fleshed papayas are becoming increasingly popular.
Where can I get seed or planting material?
Most papaya varieties are hybrid or specialist lines and are produced by professional seed producers. A list of commercial seed producers and nurseries is available from DPI&F.
Seed of Sunrise Solo has usually been sourced from the University of Hawaii.
There is growing interest in the use of tissue-cultured and vegetatively propagated material as planting material.
Money
What area do I need to grow to make a living?
A reasonable area for a family farm is 2 ha under production with about 10 ha available for rotation. A larger area, between 2 and 4 ha under production, is needed in lower yielding regions.
How much money can I make?
Returns from papaya vary according to supply and demand, and fluctuate widely between and throughout years. They can range from $4 to $45 per carton because of variations in supply and fruit quality. Papayas are severely affected by adverse climatic conditions, particularly strong winds, storms, tropical cyclones and floods, and these events will affect profitability.
Based on an average production of 6600 cartons per hectare per crop cycle in north Queensland and an average price of $15 per 13 kg or 30 L carton, you would expect a gross income of $99 000 per hectare. Assuming variable costs range between $55 000 and $86 000 per hectare, a gross margin of between $13 000 and $44 000 per hectare can be expected.
Farm overheads, living expenses and labour supplied by the grower or the grower's family are not included in a gross margin.
Growing the crop
What plant and row spacings should I use?
Most growers use a double row with 2 m between plants and 4 m between the centres of the double rows. In areas of high humidity and high disease pressure, a single row system with rows 3 m apart and plants 1.8 m apart in the row is recommended.
Should I use transplants or direct-seeding to establish the crop?
In south-east and central Queensland you should only use transplants. In north Queensland you can use transplants or direct-seeding. Avoid direct-seeding during wetter months.
What soil is best?
There is no preference for soil type for papaya. The most important considerations are surface and internal drainage. The minimum depth of free draining soil should be 50 cm.
When do I plant?
In coastal north Queensland most papayas are planted from March to May and September to November. In central Queensland and the Atherton Tablelands, planting is from March to May and in October. Papayas are planted between February and March in south-east Queensland, before temperatures get too cool.
What sex ratio should I use?
For dioecious lines (male and female flowers are on separate plants), the standard practice is to prune out excess male trees to achieve one male tree for every 10 female trees. For bisexual varieties you should aim for all bisexual plants and remove all female plants.
Can you sex plants before flowering?
No.
How long from planting to harvest?
Fruit can be harvested ten to 16 months after planting, depending on the time of year you planted and the district.
How long do papaya plants last?
Papaya plants last from two-and-a-half to four years, depending on the region. Commercial plantations are ploughed out when the trees grow too tall for easy picking or when too many trees have died from disease.
Can I grow papaya organically?
Yes, but pests and diseases can be very hard to manage. You should consider a drier or more isolated environment if you want to grow papaya organically.
Why should I mound papaya?
Mounding will improve soil drainage and decrease the incidence of root rot. Mounds are particularly important in high rainfall areas.
Can I ratoon my crop?
Trees can be ratoooned, depending on the weather and providing they are growing strongly and no more than 20% of the plantation is lost from dieback and Phytophthora. In coastal far north Queensland, ratooned trees often subsequently die from root rots. Ratooning is generally more successful in drier production areas.
Fertilising
How much fertiliser do I use?
Fertiliser requirements differ greatly between production regions and this is mainly due to different growth rates, climate and soil conditions. It is difficult to recommend an amount of fertiliser without using tissue and soil analysis.
As a general rule, the following amounts (kg/ha of the element) are applied to bearing trees each year.
Table 1. Nutrient requirements for bearing trees in different growing regions
|
South-east Queensland |
Central Queensland |
North | |
|
Nitrogen (N) |
120 |
200 |
300 |
|
Phosphorus (P) |
30 |
32 |
50-150 |
|
Potassium (K) |
90 |
200 |
570 |
Other nutrients such as calcium and magnesium, and the trace elements boron and zinc, are often required. Trace elements are very important. Pay particular attention to boron.
Irrigation
How much water do I apply?
Papayas require good soil moisture but cannot withstand waterlogging.
The actual amount required depends on:
- the environment; (The rainfall for a district/region will influence the amount of irrigation required, as will the water-holding capacity of the soil. The rainfall distribution throughout the year will also influence the amount of irrigation required.)
- stage of growth; (Different growth stages, related mostly to plant size, require different amounts of water.)
- irrigation system.
Use a soil moisture measuring device such as a tensiometer to decide how often and when to water.
Which irrigation design do I use?
Both drip irrigation and microsprinklers are suitable for papaya. We recommend you use an irrigation consultant to design your system.
Spraying
What chemicals are registered for use on papaya?
Many chemicals are registered for control of pests and diseases in papaya. Make sure that papayas are listed on the chemical label or that the National Registration Authority has a current permit in place before you use any chemical on your plantation.
Problems
Why won't my plants set fruit?
Poor fruit set may be caused by poor pollination, over- or under-watering, nutrient deficiency or other plant stress. Cold weather can affect flower development on bisexual plants. Occasionally virus diseases cause this problem.
Why don't my fruit have seeds?
Fruit do not set seeds if they are not pollinated effectively.
Poor pollination can be caused by:
- not enough male plants; (At least 10% male plants are needed to ensure there is enough pollen is available for good pollination.)
- wet weather and windy conditions;
- the overuse of insecticides, which can affect insect pollinators.
Marketing
Where can I sell papaya?
Papaya grown in Queensland can be sold in all Australian states and territories except Western Australia. Western Australia currently prohibits entry of Queensland papaya for pest and disease quarantine reasons. Fruit consigned to Tasmania, Victoria, South Australia and certain areas within New South Wales must be produced and treated under specific Interstate Certification Assurance (ICA) schemes.
What is Interstate Certification Assurance?
Interstate Certification Assurance (ICA) schemes outline the conditions under which other Australian states will accept Queensland produce. They detail the pest and disease treatments and fruit protocols that must be achieved before entry is permitted. Entry requirements may differ from state to state and between papaya varieties.
How do I sell my fruit?
There are three main markets for papaya:
- Central-agents and merchants in wholesale markets in major metropolitan centres.
- Regional-agents and merchants buying for large regional cities and towns.
- Local-flea markets, direct supply, roadside stalls.
Growers usually market independently to the central market agents or merchants.
There is potential for group marketing and directly supplying supermarket chains.
Depending on your marketing method, you may need to implement one or more components of a quality assurance or food safety scheme.
What components of quality assurance and/or food safety do I need?
The level of quality assurance or food safety needed depends on the requirements of the retailer of your fruit and your agent or merchant. The most stringent conditions are being imposed by the major chain stores. Most agents or merchants will require you to be part of an Approved Supplier Program.
The requirements of an Approved Supplier Program may differ slightly between agents or merchants, which, in turn, depends on the requirements of their customers. If you are supplying fruit direct to a regional chain store you will probably need to implement an HACCP-based quality management system. The best advice is to ask your agent or merchant or retailer for details of their requirements.
What storage temperature is best?
The best storage and transport conditions for ripe papaya are 13°C with a relative humidity of 90%.
How do I ripen fruit?
Papaya is ripened using ethylene gas under controlled conditions in special ripening rooms.
How do I pack papaya?
The fruit are packed in a single layer box. Thirty-litre cartons are generally used for yellow papaya and 18 L for red papaya. Inside the box the fruit is protected from damage with poly socks or paper wraps. Cardboard or polystyrene cartons are used.
Quarantine
What quarantine regulations govern papaya?
The Plant Protection Act 1989 prohibits the movement of papaya plants from south-east Queensland into other parts of Queensland. This is to help prevent spread of the lethal papaya ringspot virus (PRSV). Fruit movement within Queensland is not regulated. Interstate Certification Assurance (ICA) schemes outline the conditions under which other Australian states will accept papayas.
Pests, diseases and disorders
For more details, the causes and treatments, if any, refer to the Problem Solver in the Agrilink Papaya Information Kit.
How do I control black spot?
Deleaf older diseased leaves regularly and follow with strategic sprays of registered protectant and systemic fungicides incorporating a wetting agent. Begin the control program in February and continue spraying until October.
Where do I obtain biological control agents for scale?
Biological control agents for scale can be bought from suppliers of beneficial insects.
Why are my seedlings dying?
The soil-borne organisms Pythium, Rhizoctonia or Phytophthora are common causes of seedlings dying. Damage from herbicide sprays, applying too much fertiliser, too much or too little water, salinity and frost will kill young seedlings. If the seedlings are chewed off at ground level the culprit could be cutworms.
What are the spots on my leaves?
Several pests and diseases will cause spots on papaya leaves. Spots could also be due to spray burn.
Why are my plants wilting?
Lack of water or too much water is the main cause of plants wilting. Root rot disease is aggravated in very wet conditions. Severe fruitspotting bug damage will cause plants to wilt. Plants suffering the advanced stages of dieback will also wilt.
Why are my seedlings cut off?
Pests such as cutworm, grasshoppers or vermin chew through the young stalk and cut off papaya seedlings.
Why are my bottom leaves yellowing?
A range of problems can cause yellowing of the bottom leaves. These include diseases, insects, nutritional factors, herbicide damage and environmental conditions. Over- or under-watering and poor drainage can also cause the same condition.
Why are my leaves deformed?
Deformed leaves can be attributed to insects, diseases, nutritional levels or herbicide spray drift.
Why are my leaf margins brown?
The two major causes of leaf margins turning brown and dying are over-fertilising and excessive soil salinity. Tissue testing and water analysis will diagnose the cause.
Why do my crown leaves shrivel and die?
Dieback is the major cause of crown leaves shrivelling and dying. This disease is more common in central and southern Queensland, particularly during the dry spring and autumn months. Fruitspotting bug also attacks crown leaves, causing similar symptoms. Powdery mildew can also cause similar symptoms in crown leaves.
Why are my leaves mottled?
The most common causes of mottled leaves are the virus diseases mosaic or ringspot, a fungus disease called powdery mildew, or severe infestations of two-spotted mite underneath the leaves. Herbicide spray drift can also cause a mottled effect on the leaves.
Why are my leaf stalks and stems cracking?
Fruitspotting bugs feeding on leaf stalks and stems will cause them to fold in around the feeding site and then crack open. Very severe infection by the brown spot fungus can also cause this problem.
Why are my roots lumpy, bumpy or gally?
Root-knot nematode causes root swelling and galls. Control is not normally warranted. Attention to maintaining good plant vigour will keep the problem under control.
Why do my plants fall over?
The most common cause of young seedlings falling over is chewing by cutworms that eat through the stem. In older plants, root systems can be damaged and weakened by root rot or nematodes. Strong winds will blow affected plants down more easily. Some varieties are more susceptible to damage than others.
Why is my fruit going rotten?
Papaya fruit are susceptible to field and postharvest fungal rots. Any damage to green fruit can allow the growth of fungal diseases in the fruit. Pest or vermin feeding or mechanical damage of green fruit could cause this injury.
Fruit flies will lay eggs in ripening fruit. If you cut this fruit open the presence of maggots will indicate fruit fly attack. Attention to field and shed hygiene and dipping fruit in a fungicide solution will help to minimise the problem.
What are these circles on my fruit?
The papaya ringspot virus-P causes circles on the fruit. This virus is currently restricted to south-east Queensland and quarantine restrictions are in place to try to stop the disease moving throughout Queensland. If you suspect that you have papaya ringspot virus, contact your local office of the DPI to confirm the problem.
What are these spots on my fruit?
Fungi, insects and environmental factors can all cause spotting on fruit.
Why are my fruit deformed?
Fruit can be deformed and scarred as a result of severe powdery mildew. Cat-face and overcrowding of the fruit occur during cold weather. Cat-face, resulting from abnormal development of bisexual flowers, causes fruit to develop longitudinal ridges. Boron deficiency causes fruit that looks very lumpy and bumpy.
Why are my trees dying?
Depending on your location, the most common causes of premature tree death are dieback in south-east and central Queensland and Phytophthora root rot and dieback in North Queensland.
Why do my trees drop fruit?
The most common reasons for fruit drop include severe environmental conditions such as hot dry weather and boron deficiency.
What causes the lumps in papaya flesh?
The cause of lumps in papaya flesh is unknown. It is possibly a physiological problem related to growing conditions.
Why are my leaves falling off?
Heavy rain, waterlogging, heavy incidence of leaf spot diseases or poor nutrition can all cause leaves to fall.
What causes dieback?
Dieback-infected plants have been found to contain a virus-like organism called phytoplasma. Research work is being conducted into this disease.
How do I prevent root rot on replant ground?
The current recommendation is to avoid replanting on Phytophthora-infected sites. Seventy-five centimetre high mounds in single rows and improved drainage within the block will also reduce the incidence of disease.
General
Is there a papaya grower organisation?
Yes. Refer to the Agrilink Papaya Information Kit for details.
Further information
The complete Agrilink Papaya Information Kit, produced by the Agrilink Information Unit of the DPI&F, provides information on all aspects of growing and marketing papaya in Queensland.
The kit includes the following sections:
- Before you start
A checklist of things you need to know before you start growing the crop. - Common questions
The 20 or so most commonly asked questions about growing the crop. - Growing the crop
Our guide for establishing, producing and marketing the crop. - Key issues
Detailed information on the key decisions affecting the crop. - Problem solver
A picture series of the common problems and how to solve them. - Contacts and references
A list of industry organisations, product suppliers, and further reading. - Index
An A to Z index to help you find information quickly. - Your information
A place to store your special information.
Contact Agrilink on our Infoline on 1800 677 640, by e-mail to agrilink@dpi.qld.gov.au or via the Agrilink web site www.dpi.qld.gov.au/agrilink/ to order the kit or for further information on the Agrilink series.
For commercial enquiries on papayas, contact:
DPI&F Business Information Centre. Phone 13 25 23 (Queensland residents, 8.00 a.m. to 6.00 p.m. weekdays). Non-Queensland residents: Phone (07) 3404 6999. Email: callweb@dpi.qld.gov.au .
Information contained in this publication is provided as general advice only. For application to specific circumstances, professional advice should be sought. The Department of Primary Industries and Fisheries, Queensland has taken all reasonable steps to ensure the information in this publication is accurate at the time of publication. Readers should ensure that they make appropriate inquiries to determine whether new information is available on the particular subject matter.
Last updated 19 December 2005
