Pawpaw tree does well in climate that has a rainfall of about 1000mm with attitudes below 2100 m above sea level. Temperature should be between 21-30 degrees centigrade. Soil is not a big issue as long as it can’t be water logged and has a pH of between 6.0 -6.5.
Propagation
- Make holes of 1cm deep 15cm apart and put your 4-5 seeds then cover them.
- Give the seedlings 2-3weeks to germinate, you can reduce the seedlings to 3-4 after germination and give the seedling 4-5 weeks. At this time the seedling will be about 20cm tall and ready for transplanting.
- Plant seedlings in a 60cm deep 60cm wide hole at a distance of 3m apart. Mix 18kg of manure and 60g of double phosphate fertilizer and add it to the soil
- Top dress the seedlings with 40g 0f CAN fertilizer each. Remember, you will have to always add 200g of CAN or ASN each year for the next 4-5 years(economic period)
Intercropping
Papaya grows best when planted in full sunlight. However, it can be planted as an intercrop under coconut, or as a cash crop between young fruit trees such as mango or citrus. Low growing annual crops such as capsicums, beans, onions and cabbages are suitable good intercrops.
Manure and fertilizer
- Apply manure at the rate of 40kg per tree before the rains begin every year. It should be applied around the plant basin and incorporated well into the soil.
- Apply 40g of CAN per tree two months after transplanting in the first year. If possible apply a split application of 60g CAN per tree at the beginning of the long and short rains. After which 200g of compound fertilizer can be applied per tree per year at the beginning of the rains.
Major Pests
- Fruit flies -The flies usually deposit their eggs in ripe fruit. Developing larvae cause rotting of ripening fruits.
Control-Fruit should be harvested at the mature green stage. Over ripe and infested fruit should be buried.
- Red Spider Mites– Mites suck the plant sap, leading to poor plant growth and blemishes on the fruit. Serious infestations occur during long dry periods
Control-Use recommended miticides
- Root-knot nematodes– Cause root swellings or root galls, resulting in yellowing and premature abscission of the leaves. Infestation by nematodes reduces growth and yield.
Control-Do not replant pawpaw in the same field.
- Birds- They feed on the ripe fruit.
Control-Harvest when the fruits are physiological mature)
Major Diseases
- Damping-off and Foot rot– caused by soil-borne fungi, and result to rotting of roots, stem and fruits.
- Powdery mildew– As the fruits develop, the white mould disappears leaving grey-scarred areas. (Use sulfur based fungicides)
- Papaya ring spot virus (PRSV) – virus is spread by aphids and it is also mechanically transmitted. Severely infected plants do not flower and they die young. Infected fruits develop characteristic line patterns, which form rings and remain green when fruits ripen. (Destroy infected plants, doo not intercrop with host plants e.g. cucurbits).
- Anthracnose -causes fruits to rot and makes them unmarketable
Control-Immersing fruits in warm water at 400 C for 20 minutes can control the fungi infection).
- Rhizopus– It is a common postharvest disease of the pawpaws and is important only during storage and transit (sanitation in and around the packing area).
General pest and disease control-Integrated pest Management is the recommended that includes good cultural practices, biological and chemical control.
Harvesting
The stage of physiological development at the time of harvest determines the flavour and taste of the ripened fruit.The appearance of traces of yellow colour on the fruit indicates that it is ready for harvesting. Fruits harvested early have longer post harvest life, but give abnormal taste and flavour. The fruits also tend to shrivel and suffer chilling injuries when refrigerated.
Post harvest handling
- The fruits should be handled carefully and should not be stored for many days. Under ripe fruits may be stored for almost 3 weeks and then removed to room temperatures to complete ripening. Fully ripened fruit can only be stored for 2 – 3 days at room temperature.
- The fruit is twisted until the stalk snaps off or cut with a sharp knife. Yields per tree vary from 30 to 150 fruits annually, giving 35 to 50 tons of fruit per ha per year.
Challenges in production
The major problem faced in papaya production is significant post-harvest losses along the marketing chain. Factors such as fungal diseases, physiological disorders, mechanical damage, or a combination of these are the leading causes of post-harvest losses
Lack of quality planting material/seed is a serious draw back in production Most often farmers plant poor quality pawpaw of low market value and in some cases diseased material is used hence reducing economic lifespan of the orchard.