What does it look like?
Spiny Emex is a low-lying and hairless annual herb. It spreads from a dense rosette and has a thick taproot. The leaves are a dull green colour and are very similar to docks in shape.
Flowers are unassuming and are produced in clusters between the leaves and stem. Fruits (or burrs) are in clusters, with each of the three-cornered burrs forming in the forks of the leaves. When shed, ripe burrs settle with a single sharp spike pointing upward.
Why is it a problem?
Spiny Emex has hard and spiny fruit with three points. This fruit can injure animals and cause lameness, plus hurt humans too. Wool can be downgraded when it contains these seeds. Spiny Emex contains oxalate levels which are high enough to poison sheep if they eat substantial amounts.
Control methods
In Hawke’s Bay, control is achieved mainly by grubbing, as Spiny Emex is only found in small, isolated sites. It’s susceptible to Glyphosate, and hormone herbicides can be used at the rosette stage only - e.g. MCPA or 24D.
More information
In Hawke’s Bay, it’s only known to exist in two areas – just north of Napier on the coast and at Whakaki north of Wairoa
Related links
Notify Council
If you think you've found this pest, please get in touch with our Biosecurity Team at biosecurity@hbrc.govt.nz or call us on 0800 108 838.
Management Programme
Eradication Programme
An Eradication Programme attempts to reduce a pest's level of infestation to zero, across an infestation zone, over a specified time frame. To be successful; the rate of removal must exceed the rate of increase of the pest, reinvasion from other areas must be prevented, and all potentially reproductive individuals must be targeted. For these reasons, eradication programmes require robust design, efficient implementation, sufficient money, and trained field staff to be successful.
More informationUnwanted Organism
An unwanted organism is any organism that's capable of causing harm to natural or physical resources (like forests and waterways) or human health. A number of introduced pests in New Zealand are classed as unwanted.
More informationRules
Sections 52 and 53 of the Biosecurity Act (1993)
No person shall knowingly communicate, cause to be communicated, release, or cause to be released, or otherwise spread any pest or unwanted organism, in accordance with Sections 52 and 53 of the Biosecurity Act 1993
More information
