From Research to Reality

Ustilaginoidea virens

Overview

  • Scientific Name :- Ustilaginoidea virens
  • Type :- Fungal pathogen ( ascomycotina )
  • Disease caused :- False Smut of Rice
  • Host :- Rice ( Oryza sativa )
  • Plant part affected :- Spikelets
  • Symptoms :- Enlarged, velvety green balls replace the spikelets, later turning yellow-black

Basic Info

Ustilaginoidea virens is a floral stage fungal pathogen causing false smut of rice. It infects individual florets during panicle emergence forming grain like masses of clamydosopres. These smut balls reduce quality of grains and can also produce toxins called Ustiloxns which is harmful to humans and cattle.. Spread of this pathogen is favored by high humidity, moderate temperature, and excess nitrogen. It survives in soil or crop debris and spread through air borne conidia.

Taxonomy

RankClassification
DomainEukaryota
KingdomFungi
Phylum (Division)Ascomycota
SubphylumPezizomycotina
ClassSordariomycetes
SubclassHypocreomycetidae
OrderHypocreales
FamilyClavicipitaceae
GenusUstilaginoidea
SpeciesUstilaginoidea virens (Cooke) Takah.

Classification consistent across EPPO database and GBIF confirms placement under Ascomycota → Sordariomycetes → Hypocreales → Clavicipitaceae BioMed Central+3EPPO Global Database+3GBIF+3.

Despite its smut-like symptoms, U. virens is not a Basidiomycete (true smut fungus) but an Ascomycete—this is a frequent source of confusion

Key Points

  1. It is spread through asexual spores known as chlamydospores present in smut balls ( primary inoculum )
  2. It infects during flowering stage.
  3. It thrives in 90%<RH, 25-30°C Temperature.
  4. Secondary spread – airbrone – through conidia

Other Relevant Info

It produces toxic substance called Ustiloxns which is hatmful to humans and cattle.

Related Topics

  1. Chlamydospore
  2. False smut
  3. Foral pathogen
  4. Rice panicle disease

Reference Sources

  1. Plant pathology- R. S. Singh
  2. CABI. (2024). Ustilaginoidea virens (false smut). Crop Protection Compendium.
    https://www.cabidigitallibrary.org/doi/10.1079/cabicompendium.55958

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