| Sarocladium oryzae | |
|---|---|
 | |
| Rice flag leaf sheath and head infection symptoms of sheath rot | |
Scientific classification | |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Sordariomycetes |
| Order: | Hypocreales |
| Family: | Sarocladiaceae |
| Genus: | Sarocladium |
| Species: | S. oryzae |
| Binomial name | |
| Sarocladium oryzae (Sawada)W.Gams &D. Hawksw., (1976) | |
| Synonyms | |
| |
Sarocladium oryzae is a plant pathogen causing thesheath rot disease ofrice andbamboo blight ofBambusoideae spp. inAsia.
Sarocladium oryzae hasconidiophores which are irregularlypenicillate and slimy, 1-celledconidia.[1]
It was previously known asAcrocylindrium oryzae. For forty years prior to 2005, the industrial strain used to manufacture the antibioticcerulenin was known under theinvalidly published name "Cephalosporium caerulens", but a subculture of the originalC. caerulens strain KF-140 was subsequently shown to be conspecific withS. oryzae.[2]
Inaxenic culture,S. oryzae produces 0.3–0.627 micrograms ofhelvolic acid and 0.9–4.8 micrograms ofcerulenin per milliliter of culture medium.[3] The level of helvolic acid correlated with a higher incidence of sheath rot disease. Rice grains from infected plants were found to contain 2.2 micrograms helvolic acid and 1.75 micrograms of cerulein per gram of infected seeds, which inducechlorosis and reduce the seed viability and seedling health.[4]
The disease is found in rice plants usually injured by insects or other diseases. Hot (20–28 °C (68–82 °F)) and humid (wet) weather favour the disease. It is also associated with virus-infected plants.[5] Early symptoms are oblong to irregular spots, with gray centers and brown margins. Spots or rotting occur on the leaf sheath that encloses the young panicles. There is discoloration in the sheath. In severe infection, all or part of the young panicles do not emerge and remain within the sheath. Unemerged panicles will soon rot and produce powdery fungus growth inside the leaf sheath.[5]
Infection occurs on the uppermost leaf sheath at all stages, but is most damaging when it occurs at late booting stage.[5]
Partners of theCABI-led programme,Plantwise including theGeneral Directorate of Agriculture in Cambodia have suggested reducing the density of planted crops to 25 by 25 centimetres (10 in × 10 in) and removing infected stubble and weeds from the field. They also recommend application of fertilisers including potassium,calcium sulphate andzinc sulphate during the tillering stage to strengthen the stem and leaf tissues.[5][6]
TheBureau of Rice Research and Development, Rice Department, of Thailand recommends using disease-free seeds and plants, avoiding monocropping with any one variety of rice (planting at least two varieties in the same field), and regular monitoring of fields.[7]
This article incorporates text from afree content work. Licensed under CC-BY-SA (license statement/permission). Text taken fromPlantwise Factsheets for Farmers: Rice Sheath Rot -Cambodia, General Directorate of Agriculture (Cambodia), CABI.Plantwise Knowledge Bank.
This article incorporates text from afree content work. Licensed under CC-BY-SA (license statement/permission). Text taken fromPMDG: Rice Sheath Rot - Cambodia, GDA, Phnom Penh, Cambodia, CABI.Plantwise Knowledge Bank.
This article incorporates text from afree content work. Licensed under CC-BY-SA (license statement/permission). Text taken fromPMDG: Dirty Panicle on rice - Thailand, Bureau of rice research and development, Rice Department (Thailand), CABI.Plantwise Knowledge Bank.
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