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Source: The News International [summ. Mod.DHA, edited]

Banana plantings in Sindh have been struck by Panama wilt, a soil-borne fungus that originated in Tando Allahyar district. The Agriculture Extension Department said not following standard operating procedures and not keeping infected plants under quarantine may lead to colossal losses for farmers. They believe the fungus exists in all the banana fields across the province.

Researchers pointed out that the fungus was first reported in the coastal district of Thatta in 2010-2011. But authorities did not take it seriously and it was spreading. Farmers even recall the deadly disease in 1988 when it destroyed many banana fields. Researchers are keeping a close eye on the situation. Since chemical agents are not effective in managing the disease, the only options are prevention, very early recognition and rapid containment of outbreaks to prevent an epidemic.

Earlier, Sindh farmers and researchers have also found other diseases, including bunchy top, which caused the destruction of bananas in different areas.

[Byline: Jan Khaskheli]

Communicated by:

[Panama disease
Panama disease of banana (PD, also called fungal or fusarium wilt) is caused by the soil-borne fungus _Fusarium oxysporum_ (previously f. sp. _cubense_). Symptoms include yellowing, wilting and streaking of pseudostems; affected plants die rapidly. The pathogen is spread by infected planting material, mechanical means (including human and insect activities), soil and water.

Disease management for PD is difficult and mostly relies on phytosanitation for pathogen exclusion. The fungus can survive in the soil for decades; consequently, crop rotation with non-hosts is not likely to control the disease effectively. No effective chemical or cultural control measures are available. Integrated approaches have been developed (ProMED post 20090419.1483), which may include cultural practices, certified clean planting material, and biocontrol agents (e.g. ProMED post 20160317.4102576). Constant vigilance is required in areas where the fungus is present to prevent flare-ups and recognise emerging new strains.

Several races of the pathogen exist, varying in host range. Strains affecting Cavendish cultivars (_Musa_ AAA group which includes most of the current commercial varieties, see link below), such as temperate (subtropical) and tropical races 4 (TR4), as well as a new strain of race 1 (ProMED posts 20210105.8075029, 20101223.4510), have emerged from Asia and Oceania. TR4, in particular, is of great concern worldwide and consequently development of TR4 resistant cultivars has become a top priority for many national banana industries.

Bunchy top
_Banana bunchy top virus_ (BBTV) is the type member of the genus _Babuvirus_. It affects only _Musa_ species and hybrids, including bananas and plantains (banana types mostly eaten cooked). BBTV causes one of the most serious diseases of these crops with symptoms of chlorosis, stunting and death of the host plant. The virus is spreading in Africa, Australasia, and the Pacific Islands.

BBTV is transmitted by the banana aphid _Pentalonia nigronervosa_ in a persistent manner. Infectious insects may be spread on plant material or by air currents. The virus is also spread with infected suckers but cannot be transmitted by mechanical means (such as cutting tools). Disease management is extremely difficult and may include vector control, removal of inoculum, use of clean planting material, as well as frequent scouting for new outbreaks. Eradication of established BBTV from a planting or natural cluster of plants is considered impossible; the only option is to kill off all plants in the group. Tolerant varieties can be used to enable some crop production in infected areas, but these cultivars may still support virus replication and thus serve as pathogen reservoirs.

There are 2 groups of BBTV isolates from different regions: the South Pacific and the Asian groups, suggesting that the virus has spread after the initial movement of its hosts from the Indo-Malayan region, where edible _Musa_ species originated. BBTV is closely related to _Abaca bunchy top virus_ (ProMED post 20191215.6842101) affecting _M. textilis_.

In Pakistan, race TR4 was first officially confirmed in Sindh in 2015 (ProMED post 20150402.3271568). There seems to be no information available on what strains were represented in any earlier reports of PD in the country. Bunchy top so far seems not to have been reported officially in Pakistan, but is known to be present in the region. Therefore, its presence in the country may well be expected.

Pakistan: and (provinces)
Sindh districts:

PD symptoms on banana:,, and

PD-affected plantations:,, and

Bunchy top symptoms on banana:, and

Bunchy top photo galleries: (whole plants), (leaves), (fruits) and (banana aphids)

Information on Panama disease:,,,, and

Information on race TR4:,,, and

FAO emergency project for TR4: and
_F. oxysporum_ taxonomy and synonyms: and

Information on BBTV:,, and

BBTV description and genetic groups:
Information on genus _Babuvirus_:

Virus taxonomy via:
Information on the banana aphid:

Cultivars and hybrids of banana and plantain: and
- Mod.DHA

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