A ProMED-mail post
ProMED-mail is a program of the
Date: Tue 15 Apr 2014
Source: Oheraldo [edited]
"Rice blast" has hit Salcete area [South Goa district] with large-scale destruction of paddy cultivation by the disease. While the disease had raised its ugly head in [several towns], Curtorim farmers were the worst hit, leaving them without any produce or return.
[Farmers said that] the agriculture department gave fungicide and pumps, but it has not worked. The farmers have suffered heavy losses.
Zonal Agricultural Officer Sandeep Fal Desai confirmed that the paddy cultivation is hit by the rice blast disease. "While the paddy recovered after farmers sprayed fungicide in [some of the towns], the situation turned worse in Curtorim," he confirmed. He said there's no provision for compensation when the crop is hit by a disease.
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ProMED-mail
[Rice blast is caused by the fungus _Magnaporthe oryzae_ (previously classified as a strain of _M. grisea_, synonym _Pyricularia oryzae_).
It is one of the most destructive diseases of rice worldwide, with potential yield losses of more than 50 percent. Symptoms include lesions on all parts of the shoot, as well as stem rot and panicle blight. When nodes are infected, all plant parts above the infection die, and yield losses are severe. When infection occurs at the seedling or tillering stages, plants are often completely killed. More than 50 species of grasses and sedges can be affected by related pathogens, but most strains isolated from rice can only infect a limited number of cultivars.
Symptom severity and spread of the blast fungus are influenced by climatic conditions. The disease is also favoured by high nitrogen levels (for example from fertilizers) and high humidity. The fungus is spread by infected plant debris, mechanical means (including insect activity), water and wind. Disease management may include fungicides and cultural practices but relies mainly on resistant varieties.
However, the fungus is highly variable, and this favours the emergence of new strains with increased virulence.
It is reported above that fungicides were not effective in only one of the towns (Curtorim). While it is not impossible that a new resistant pathogen strain may have emerged there, it appears more likely that the failure may be due to mistakes in the application or dosage of the chemicals.
Maps
India:
Goa:
Salcete area with location of Curtorim:
Pictures
Leaf:
Neck:
Leaf, collar, node, and neck:
Links
Information on rice blast:
(with pictures),
Perceived impact of fungal crop diseases:
_M. oryzae_ taxonomy:
- Mod.DHA
A HealthMap/ProMED-mail map can be accessed at:
[See Also:
2013
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Blast disease, rice - India: (TN) 20131231.2144256 Fungal diseases, rice - USA, India 20130905.1926343
2012
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Blast disease, rice - Nigeria: (KD) 20121105.1391776 Blast disease, rice - Australia: (NT) 20120217.1044294 Blast disease, rice - Malaysia: (KH) 20120103.0015
2011
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Blast disease, rice - Nepal: (JU) 20111111.3339 Blast disease, rice - Australia: (WA) 20110812.2442 Blast disease, rice - Philippines: (KA) 20110801.2311 Blast disease, rice - Kenya: (CE) 20110704.2025 Rice diseases - Costa Rica, Bangladesh 20110425.1289
2010
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Topics
Species
