Noogoora Bur
| Botanical Name | Xanthium strumarium |
|---|---|
| Family | Asteraceae |
| Origin | Native of America |
Identification
Annual herb to 2.5 m high. Stems rough to touch with short stout upward-directed hairs, green and usually blotched or streaked purple. Stem is spineless. Leaves ovate or triangular, 50 - 150 mm long with 3 - 5 lobes and coarsely toothed. They are dark green above, paler below, covered with small bristles and hairs, with 3 prominent veins. Brown burs 7-25 mm long, covered with hooked spines and ending in 2 diverging stout straight spines. Each bur contains two brown, grey or black seeds.Habitats
Temperate regions, usually in fertile soils, occurring as a weed of cultivation, cropping and along roadsides. Often found close to water courses and areas where soil has been disturbed as this activates long-dormant seed if the land has been previously infested.Impact to Biota and Ecosystems
A strong invasive plant with a rapid growth rate means it competes with crops and pasture. Seeds last many years in the soil and may germinate when soil is disturbed. Young plants are toxic to sheep, cattle and pigs. Can cause dermatitis to humans and animals.Dispersal Routes, Vectors, Infestation Sources
Spread by seed in burs. Burs are spread because of the spiny hooks and can attach to animals, clothing and bags. Burs float and are moved by water. Noogoora bur can be abundant after spring and summer floods.Management
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Management |
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| Physical Control |
Early control is essential in order to prevent the formation of burs. Hand pulling plants before burs set is recommended. |
| Disposal |
Plants should then be incinerated to kill seeds. |
| Chemical Control |
Glyphosate at 100 ml/10 L water plus 20 ml organo-silicone pentetrant, applied in spring/ early summer to young actively growing plants. Herbicides used in controlling annual weeds in maize at recommended rates are suitable. |
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Biological Control |
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| Recommended Approach |
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Further Comment
Noogoora bur has been found in maize paddocks in the Waikato and Bay of Plenty. In 2006 two new sites were found in the Bay of Plenty between Tauranga and Te Puke.