The most serious disease you may experience is a mosaic virus which stunts the plants. This causes yellow mottling and distortion of the leaves, blending down of petioles. It causes death of the tree. You will see that such diseased plants yield little or not at all. You will discover that in some areas of Nigeria it is now almost impossible to grow pawpaw on the account of the virus. This mosaic appears to be very virulent. It is caused by the vector.
Aphis spp and in Hawai, a major pawpaw producing nation, the vectors are myzus spp. The vector of the bunchy – top virus is the leaf hopper, Empoasca papaya.
Pythium spp cause a collar – and foot-rot when pawpaws are grown under water logged conditions. Anthracnose colletotrichum spp cause spotting of ripe fruits.
Mites are the most serious pests of pawpaws some birds also damage the fruits.
Exercise 10.1
Almost every part of pawpaw plant is useful one way or the other. List the major uses of pawpaw:
- The fresh fruits are eaten throughout the world for breakfast and in fruit salads.
- They are used for making soft drinks, jams, ice cream flavouring, crystallized.
- They are canned in syrup.
- Unripe fruits are cooked as a substitute for marrow and for apple source
- Papain is prepared from the dried latex of the immature fruits.
- Used in meat- tenderizing preparations
- Used in manufacture of chewing gum and in cosmetics - Young leaves are sometimes eaten as spinach
- Seeds are used as a vermifuge, counter – irritant and abortifacient
3.1.11 Production
Much of the pawpaw crop in the tropics is consumed locally, as it is difficult to transport the fruits satisfactorily over long distances. Fresh fruits are exported by air and in cold storage by sea from Hawaii to the United States, but little fresh fruits reaches other temperature countries. Pawpaws are now being canned and this market will probably increase.
Tanzania has become the leading producer of pawpaw in the world, with maximum production of about 200,000 tons per annum smaller quantities are produced in Uganda. The production in Nigeria does not meet even domestic requirement in large cities. The Chief importer of papain is the United States.
Market is very sensitive to over production.
Exercise 102
You can describe pawpaw fruit as a delicacy, loved by many people all over the world. What is the chemical composition of this fruit?.
The edible portion of fresh fruit contains approximately:
Water - 88%
Sugar - 10%
Protein - 0.5%
Fat - 0.1%
Acids - 0.1%
Ash - 0.6%
Fibre - 0.7%
Pawpaw fruit is a rich source of vitamin A and has some vitamin C. The latex contains the enzymes papain and chymopapain, both of which have protein – digesting and milk clotting properties.
4.0 CONCLUSION
We have seen through this unit that pawpaw belongs to a small family, caricaceae with four genera. You have learnt that the pawpaw we know belongs to species Carica papaya which is cultivated throughout the tropies for its edible fruits.
Pawpaw fruits are use for food; for making soft drinks and desserts. Unripe fruits are cooked as a substitute for marrow and for apple sauce. Papain is prepared from the latex of pawpaw. This papain is a proteolytic enzyme used in meat
tenderizing preparations etc. You have learnt that young leaves of pawpaw are used as spinach. Seeds of pawpaw are used as a vermifugu, counter – irritant and abortifacient.
You can propagate pawpaw by seeds, vegetatively by cuttings or by grafting.
5.0 SUMMARY
You have learnt through this unit that pawpaw can be cultivated in Nigeria. You must have also known that pawpaw has many uses and that it has been known even as domesticated crop. You now know that pawpaw is a short – lived, quick growing, soft – wooded tree, 2-10m in height the chemical composition of pawpaw. You are now in a position to propagate pawpaw from nursery to the orchard, through weed control, harvesting, storage of fruits, pests and diseases with their control measures. In Nigeria, pawpaw is produced mainly for domestic consumption but has a future in exportation.
6.0 TUTOR MARKED ASSIGNMENT (TMA)
Pawpaw is a very popular tropical fruit that is eaten as favourite all over the world. Describe the production of the tree crop under Family Genus Uses; Fruits;
Chemical composition; propagation and major diseases and pests.
7.0 REFERENCES AND OTHER RESOURCES
Purseglove, J.W. (1968) Tropical Crops Dicotyledons I. Longmans, Green and Co. Ltd London and Harlow
Module 3