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Wild Oats

There are two types of wild oats – spring (Avena fatua) and winter (Avena sterilis). Spring wild oats are the most common type in Irish tillage soils. Occasionally, fields can have a mix of spring and winter wild oats. 

Avena Fatua (Spring Wild Oats)

  • Awns are present on the third seed within the spikelet.
  • Seeds separate when mature and shed singly.

Figure 1. Spring Wild Oats

Avenua Sterilis (Winter Wild Oats)

  • Awns are absent on the third seed in a spikelet.
  • Seeds remain attached when mature and shed as a unit.

Spring Wild Oats: Key Features

  • A population of 1 plant per m2 has the potential to cause a yield loss of 1%.
  • Predominately spring germinating, but sporadic and unpredictable emergence patterns (i.e. a proportion of seedling may germinate between September and May and complicates control options).
  • Seeds can survive in soil for several years and are therefore unaffected by seed burial depth.
  • Light promotes seed germination.
  • Most seeds emerge from the top 10 cm of soil, but some emerge from greater depths (15 to 25 cm).
  • It flowers from June onwards and sheds seed from July.

A single well-tillered plant can produce up to 200 seeds.

Scorecard Wild Oats (pdf)

Spring Wild Oats: Identification

  • Leaf blades twisted anti-clockwise, which is apparent even at the 2-4 leaf stage.
  • Fine hairs along the edge of the leaf blade and sheath.
  • Ligule long (6-8 mm) and serrated.
  • Loose drooping panicle.
  • Leaves rolled in shoot.

Figure 2. Spring Wild Oats Identification

Figure 3. Spring Wild Oats vs Winter Wild Oats