Weed Seed: Raphanus raphanistrum (Wild radish)

Family

Brassicaceae

Common Name

Wild radish

Regulation

Primary Noxious, Class 2 in the Canadian Weed Seeds Order, 2016 under the Seeds Act.

Distribution

Canadian: Occurs in all provinces but not in the territories (Darbyshire 2003^Footnote 1, Brouillet et al. 2016^Footnote 2).

Worldwide: Native to northern Africa, Europe and western Asia and the Caucasus. Introduced in North and South America, elsewhere in Africa and Asia, Australia and New Zealand (USDA-ARS 2016^Footnote 3). It occurs throughout the United States, except for the central region (Kartesz 2011^Footnote 4).

Duration of life cycle

Annual, winter annual or biennial

Seed or fruit type

Seed, often in a pod segment

Identification features

Size

• Seed length: 2.5 - 4.5 mm
• Seed width: 2.3 - 3.5 mm
• Pod segment length: 4.0 - 5.5 mm
• Pod segment width: 2.5 - 3.0 mm

Shape

• Seed oblong to oval
• Pod segments are cylindrical; barrel-shaped

Surface Texture

• Seed reticulate surface with small, shallow interspaces
• Pod segments smooth or strongly ridged

Colour

• Seed reddish-brown with a darker area at the hilum
• Pod segments yellow or greyish-brown

Other Features

• Pods break up at maturity into one-seeded, cylindrical segments

Habitat and Crop Association

Cultivated fields, abandoned fields, gardens, grasslands, meadows, orchards, woods, cliffs, riverbanks, beaches, dunes, roadsides, railway lines and disturbed areas (Darbyshire 2003^Footnote 1, Warwick and Francis 2005^Footnote 5). In Canada, a weed of hay, cereals, corn, canola, clover, peas, lupins, potatoes, strawberries, onions, bulbs and hops (Warwick and Francis 2005^Footnote 5).

General Information

Wild radish seeds may be dispersed as a contaminant of commercial cereals, as pod segments are a similar size to grains (Warwick and Francis 2005^Footnote 5).

Mature seedpods usually fracture into one-seeded pod segments and approximately 10% are released as seeds (Warwick and Francis 2005^Footnote 5). Seed is also dispersed by water and in the gut of many animals including birds and cattle. Seeds may remain viable in the soil for 15-20 years (CABI 2016^Footnote 6).

Similar species

Radish (Raphanus sativus)

• Radish seeds are a similar shape, colour and have similar surface reticulations as wild radish.
• Radish seeds (length: 3.3 - 5.0 mm; width: 2.8 - 5.0 mm) are generally larger sometimes have a pointed hilum end, slightly compressed and the surface reticulations are heavier than in wild radish.

Photos

Similar species