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BACTERIAL LEAF BLIGHT, RICE - PAKISTAN (SINDH, PUNJAB)

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Bacterial leaf blight (BLB) has attacked rice crops in the country as 

50 000 acres (20 234 hectares) of cultivated land in Sindh and large 

areas of Narowal, Sheikhupura, Sialkot, and Hafizabad districts of 

Punjab have been affected by the disease. The pest attack would 

definitely slash production of rice in the country this year [2007], 

which would eventually reduce foreign exchange earnings.



In a statement issued on Tuesday [2 Oct 2007], Chairman of the Rice 

Committee of Kisan Board Pakistan, Aman Ullah Chatha, stated that 

last year (2006-07) the area cultivated with rice crop rose 0.2 

percent to 258 000 acres (about 104 410 hectares), but production 

dropped by 2 percent at 5438 million tonnes against the target of 

5693 million tonnes. He said during the last 4 years, BLB had created 

problems for the rice growers but the agriculturists failed to 

eradicate it or overcome the disease.



He said the stockists had reduced the price of the rice variety 386 

from PKR 700 (USD 11.53) per 40 kg to PKR 575 (USD 9.47). So, like in 

the past they would again mint money and the growers would fail to 

get advantage of their crop, he remarked. He demanded the government 

take the necessary steps to stabilise rice prices, as the stockist 

mafia would again create artificial shortages like they did in the 

case of wheat.



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[Bacterial leaf blight (BLB) of rice is caused by _Xanthomonas 

oryzae_ pv. _oryzae_ (previously _X. campestris_ pv. _oryza_). It was 

1st noticed in Japan in 1884 and has since been reported from Asia, 

northern Australia, Africa, and the USA. The pathogen causes 

yellowing and drying of leaves, wilting of seedlings, and reduces 

yield. In Asia, millions of hectares of rice paddies are severely 

affected every year with reported yield losses of up to 60 percent. 

Mild strains of the bacterium are also known, for example in the USA, 

which do not cause any detectable yield loss.



Blight lesions caused by severe strains of the bacterium elongate 

over the entire length of the flag leaf, giving a striped appearance 

to leaves. Lesions caused by mild strains are usually only a few 

centimeters long. Various saprophytic fungi may invade the lesions, 

contributing to the damage. Panicles may be infected by the severe 

strains. Field patches infested with bacterial blight have a whitish, 

ragged appearance.



The bacterium is short-lived in soil and suspected to be seedborne, 

but also to be short-lived in seeds. Grassy weeds, infected plant 

material, such as rice stubble or ratoons, and contaminated 

irrigation systems are thought to be the primary pathogen reservoirs. 

The disease spreads by windblown rain and mechanical means (for 

example when transplanting seedlings) and is favoured by rain, high 

levels of fertilizer, high humidity, standing pools of water, and 

temperatures above 25 deg C (77 deg F).



A different pathovar (strain) of the same species, _X. oryzae_ pv. 

_oryzicola_ causes bacterial leaf streak of rice. It occurs in Asia 

and West Africa and yield losses of up to 30 percent have been 

recorded. Symptoms vary early on, but in the later stages of the 

disease look similar to BLB.



Variety 386 is a cultivar of basmati long grain rice suitable for 

rain fed cultivation in lowlands. India and Pakistan are the largest 

producers of basmati rice. Basmati plants are delicate, prone to 

breaking, and have a relatively low yield, but produce high-quality grains.



Map of Pakistan



Pictures



Links

and



Bacterial leaf blight, rice - India (Punjab) 20070824.2775

2005

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Flag smut, bacterial leaf blight, rice - India (Punjab & Haryana) 

20050927.2841]

...................................dha/mj/mpp