ProMED
http://www.promedmail.org

Source: The Indian Express [summ. Mod.DHA, edited]
https://indianexpress.com/article/cities/chandigarh/farmers-report-foot-rot-disease-in-basmati-experts-say-junk-saplings-grow-fresh-batch-8643676/

Rice farmers said they have seen foot rot on seedlings in the nurseries, but only in the basmati variety. The Punjab Agriculture Department said that to control the disease, treatment of seedlings is mandatory and should be carried out as early as possible. It is important to use disease-free, treated seeds and to destroy infected seedlings. Seeds and seedlings can be treated with trichoderma or fungicides. They advise to discard the infected seedlings and grow a fresh batch.

[Byline: Anju Agnihotri Chaba]
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Communicated by:
ProMED

[Fungal foot rot (also called bakanae disease) of rice is reported from rice growing countries worldwide, except for Australia. A different foot rot disease of rice can be caused by several species of bacteria in the genus _Dickeya_ (see previous ProMED posts in the archives). Since fungicides are suggested above, the fungal disease seems to be thought to be involved.

Bakanae is caused by _Fusarium fujikuroi_ which is now considered a species complex that can also affect other crops, including maize (_Zea mays_; kernel rot), sorghum (_Sorghum_ spp.) and sugar cane (_Saccharum_ species and hybrids; pokkah boeng, see ProMED post 20200717.7582937).

Bakanae can cause significant crop losses of up to 50% in rice and is emerging as a major problem in Asia. Symptoms on rice may include abnormal growth patterns (such as highly elongated tillers), reduced tillering, partially filled or empty seed heads. Diseased plants show yellow-green discolouration; their leaves dry up quickly, they may be distributed irregularly in a field. Infected seedlings with necrotic lesions on roots may die before or after transplanting from seed beds.

Plants get infected through roots or crowns, the infection later becomes systemic. Seeds are usually infected during the flowering stage, the disease is primarily seed borne. The fungi survive under adverse conditions in infected seeds and diseased plant parts. Disease management is difficult and may include use of certified clean seeds, fungicides (such as seed treatments or root dips), phytosanitation and use of crop cultivars with reduced pathogen sensitivity. Rapid development of new pathogen strains with fungicide resistances or ability to break genetic host resistance has been observed.

Traditional rice cultivars previously grown across northern India have largely been replaced by basmati (aromatic long grain) varieties. Some basmatis have shown higher sensitivity to certain pathogens (e.g. also to rice blast, _Pyricularia oryzae_; ProMED post 20160407.4145967).

Antagonistic fungi in the genus _Trichoderma_ have been shown to be effective as biocontrol organisms to suppress various fungal pathogens including soil-inhabiting species (e.g. ProMED posts 20160317.4102576, 20151109.3779551, 20130805.1864259). They are used as foliar applications as well as seed and soil treatments.

Maps
India (with states):
https://www.worldometers.info/img/maps/india_physical_map.gif

Pictures
Bakanae symptoms on rice:
https://www.krishisewa.com/images/articles/2014/june/dbrice1.jpg,
http://www.knowledgebank.irri.org/smta/images/stories/Module2/newdiseasesimages/bacanae/field.jpg,
https://media.springernature.com/lw685/springer-static/image/art%3A10.1007%2Fs42360-018-0091-2/MediaObjects/42360_2018_91_Fig2_HTML.jpg,
https://i.ytimg.com/vi/oh7VA5WQpmU/maxresdefault.jpg and
http://www.knowledgebank.irri.org/smta/images/stories/Module2/Seed%20infected%20with%20Fusarium%20moniliforme.jpg (infected seed)
_Trichoderma_ hyphens, microscopy:
http://life.nthu.edu.tw/~b831603/homework/image/background/trichoderma.jpg

Links
Information on bakanae disease:
http://www.knowledgebank.irri.org/training/fact-sheets/pest-management/diseases/item/bakanae
https://doi.org/10.1079/cabicompendium.25158,
https://www.dpi.nsw.gov.au/biosecurity/plant/insect-pests-and-plant-diseases/Bakanae,
https://doi.org/10.1007/s42360-018-0091-2 and
https://apps.lucidcentral.org/ppp/text/web_full/entities/rice_bakanae_disease_429.htm
Information on _Trichoderma_ spp. and use for biocontrol:
https://biocontrol.entomology.cornell.edu/pathogens/trichoderma.php,
https://doi.org/10.1007/s00253-010-2632-1 and
http://benthamopen.com/contents/pdf/TOMYCJ/TOMYCJ-8-71.pdf
All fungal taxonomy & synonyms via:
http://www.indexfungorum.org/names/Names.asp
Basmati rice varieties in India:
http://www.apeda.gov.in/apedawebsite/SubHead_Products/Basmati_Rice.htm and
https://business.mapsofindia.com/top-brands-india/top-basmati-rice-brands-in-india.html
- Mod.DHA