Banana is extensively grown in the lower part of Sindh where the soil and climatic conditions are favorable for its successful cultivation. The total share of Sindh province alone in its cultivation in the area is 87 per cent and 89 per cent in production.

Major districts in Sindh where banana is grown are Thatta, Hyderabad, Badin, Mirpurkhas, Sangar, Nawabshah. Recently its cultivation has been extended from Khairpur to Sakkur. Mostly Basrai variety (Cavendish dwarf) and William Hybrid are grown in Khairpur.

Previously, the disease problem was not serious in Pakistan as compared to other parts of the world such as Australia, Panama, Surinam, Central America, India and Colombia. In December 1988, some unknown disease was reported from the Thatta district at Gorabari and Mirpur Sakro. It received public attention in April 1989 when the disease has damaged more than 50 per cent of the banana crop in that area.

Now the disease has spread in the districts of Thatta, Hyderabad, Tharparkar and Nawabshah and covered more than 90 per cent of the area in individual fieldsI. In 2001 the disease appeared with low intensity in Karachi, Mirpurkas and Sakkur and other districts. About 50-60 per cent of the crop has been damaged. The disease has now spread over more than 50 per cent of the total area.

A single vector transmits BBTV semi-persistently; the honeydew that the aphid produce attracts the banana black aphid, and the black ants, which live mutually with black aphid. Black aphid appears in the months of September to December. Sometimes the damage caused by BBTV disease is overlooked due to the apparent losses due to Fusarium wilt and Sigatoka diseases, and banana plants are considered to be free from BBTV.

BBTV is widespread in tropical and subtropical Asia. It was first reported in Fiji in 1889 and Taiwan in 1900. Nohara also reported it in Okinawa, Japan, in 1968. In almost all these countries except for the islands located in Micronesia, banana plants were found to be infected with BBTV. The existence of BBTV was newly confirmed by ELISA (enzyme linked immuno-sorbent assay) tests in Indonesia (1989). Symptoms:The first symptoms of the virus consist of darker green streaks on the lower portion of the midrib, and later on the secondary veins of the leaf.

The symptoms can become more pronounced in the months of February to October. Removing the “white fuzz” or wax covering the midrib makes it easier to see the streaking clearly, often referred to as “morse code” streaking. As infection progresses, streak symptoms become evident on the leaf blade. Suckers that develop after infection are usually severely stunted; resulting in leaves “bunched” at the top of the stem. Leaves are usually short, stiff, erect and more narrow than normal. Leaves display marginal yellowing or chlorosis and necrosis or burning.

These plants will not produce any fruit. The virus is spread by the banana black aphid, which can acquire the virus after about an 18-hour feeding period and can retain the virus for about two weeks. During this time, an aphid can transmit the disease after feeding for about two hours on a healthy plant. Disease symptoms appear approximately one month after infection.

In Sindh the most prominent feature for disease spread is through infested suckers/stools.

Control: Complete control of the aphid vector and proper removal of diseased mats are the most important factors for disease management. The first step in disease management is effective aphid control. The uses of contact, systemic insecticides are suggested because of their residual anti-aphid activity. Regular inspection of the fields to locate bunchy top infected plants, spraying them with kerosene oil only after the suspected mat is entirely rooted out followed by cutting, removal of infested mat out of field and burning have been advocated as in Australia (Dale, 1987) and at Asim Agriculture Farm Tando Allahyar, Sindh.

Furthermore, quarantine laws should be revised and strictly enforced on the import of new suckers and on the movement of infected suckers within the country. With the use of tissue culture techniques disease free planting material (suckers) can be produced and used for new plantation.

Conclusion: Systems for the integrated control of virus disease of banana have five basic objectives:

1) development of a production system for virus-free seedling;

2) protection of seedlings from the attack of viruliferous vectors;

3) elimination of virus sources;

4) development of highly trained and skilled manpower, and

5) development of highly advance communication networks within the country. Various techniques are currently available for achieving these objectives and are applied in a number of countries in this region. However, these have not been achieved and practiced in our country.