.

October 4, 2007
Source: Dawn [edited]
<http://www.dawn.com/2007/10/04/nat23.htm>


A viral disease identified by agricultural experts as "poppy" has hit a major part of paddy crops in Thul taluka [Jacobabad district, Sindh] throwing the farmers into limbo.

Talking to Dawn, MPA (member of the provincial assembly) Mir Nasir Khan Khoso said that the disease, which dries the leaves of the paddy crop, is contagious. He said that the disease has caused 30 per cent damage to Irri and 50 per cent to Basmati, cited as cash crops for the country.

He said that no fruitful results could be achieved despite spray of almost all types of pesticides including poisonous ones against the fast spreading disease. The worst affected included agricultural fields in deh Madadpur, deh Sarki, and deh Korar, he added.

He said that the disease could not be controlled despite implementation of proposals and suggestions of the agriculture experts and it was increasing with each passing day. He also complained of non-serious attitude of the local authorities in containing the disease.

--
communicated by:
ProMED-mail
<promed@promedmail.org>

[The name "poppy" for a disease of rice is obviously local and not recorded in any official sources. There are at least 15 viruses known to affect rice with a number of insect vectors involved. Many rice viruses have become serious problems since rice cultivation has been intensified, and it is possible that a virus problem has arisen in the area.

However, the report of a "viral" cause may be an error and this report may in fact refer to bacterial leaf blight which has broken out in other parts of Sindh and Punjab. Bacterial leaf blight (BLB) of rice is caused by _Xanthomonas oryzae_ pv. _oryzae_. Severely infected leaves tend to dry quickly (like the symptoms described above). Disease management relies mostly on cultural practices and use of resistant host cultivars. For more information on BLB and the recent outbreak in Pakistan see ProMED-mail post 20071005.3293.

Chemical treatments are reported to have failed in the affected area. This scenario would fit either BLB or a virus: chemicals are usually not very effective for control of BLB, and in case of a virus they would only be effective if a potential insect vector was involved.

The International Rice Research Institute (IRRI) has developed a number of rice varieties and hybrids (_indica x japonica_ subspecies) suitable for a range of growing conditions. It is not stated which particular cultivars are grown in the affected area. Basmati is a long grain rice for which India and Pakistan are the largest producers worldwide. Basmati plants are delicate, prone to breaking, and have a relatively low yield, but produce high quality grains.

Map of Pakistan
<http://www.lib.utexas.edu/maps/middle_east_and_asia/pakistan_pol_2002.jpg>
Pictures of BLB symptoms on leaves and whole plants via:
<http://www.invasive.org/browse/subject.cfm?sub=11182>
Links
BLB disease information:
<http://www.knowledgebank.irri.org/riceDoctor_MX/Fact_Sheets/Diseases/Bacterial_Leaf_Blight.htm> 

Information on other rice diseases via:
<http://www.knowledgebank.irri.org/riceDoctor_MX/default.htm>
Review of rice viruses:
<http://arjournals.annualreviews.org/doi/pdf/10.1146/annurev.phyto.34.1.249?cookieSet=1> 

History and details of rice varieties:
<http://dacnet.nic.in/rice/Rice%20Varieties%20in%20India.htm>
Differentiation of _indica_ and _japonica_ subspecies:
<http://www2.tu-berlin.de/~china/deutsch/abstracts/ChenW.html>
IRRI:
<http://www.irri.org>
Information on Jacobabad, Sindh:
<http://en.wikipedia.org/wiki/Jacobabad_District> . - Mod.DHA]

[see also in the archive:
Bacterial leaf blight, rice - Pakistan (Sindh, Punjab) 20071005.3293]
 

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