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
To reduce the infestation level of the subject, or an organism being spread by the subject, to zero levels in an area in the short to medium term.
Unwanted 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.
Rules
Sections 52 and 53
Sections 52 and 53 of the Biosecurity Act 1993, which prevent the communication, release, spread, sale and propagation of pests, must be complied with.
Taxonomies
TypePlants
GroupPerennial
HabitatLand
Management ProgrammeEradication ProgrammeUnwanted Organism
RulesSections 52 and 53
