Clean your machine
A hitchiker's guide
Pest plants can be a major threat to the Bay of Plenty region’s farmland, wetlands, lakes and waterways. Seeds and small fragments of unwanted vegetation are easily able to spread by contaminated equipment and agricultural machinery. Transportation or the movement of seeds, root, stem and crown fragments propagate quickly once introduced and they can heavily impede on crops, pastures and waterways.
Many pest plant species compete with crops, outgrow native flora and fauna, are unpalatable to stock, and overcrowd and damage freshwater systems. Due to the nature of such species being out of origin, they therefore require regular and vigorous control methods.
Prevention is a useful tool in minimising the potential environmental and agricultural damage caused through the spread of pest plants. Seed, root or crown fragments that are buried in soil or present within crops, and which may come into contact with earthmoving, excavating, cultivating and harvesting machinery have the potential to establish new sites of infestation.
Major Pest Plants of Concern
The following pest plants are examples of the types of vegetation that can easily be spread by agricultural and excavation machinery. Learn to identify the following species and what you can do to minimise the spread of invasive pest plants.
Yellow Flag
Iris pseudacorus
A very leafy species which grows in clumps up to 1 m high, producing conspicuous yellow flowers in spring. Spread is by seed or by movement of the root system. Yellow flag can grow to form dense stands which exclude other desirable vegetation.
Asiatic Knotweed
Fallopia japonica
A tall, upright, shrub-like plant that can grow rapidly to 3 m in height. Once established, Asiatic knotweed forms a deep rooting system which can be difficult to remove. Asiatic knotweed forms dense stands which crowds out and shades all other vegetation and displaces native flora and fauna.
African Feather Grass
Pennisetum macrourum
A grass that forms in large clumps and has underground stems. The seed heads can grow to 2 m tall and it is a prolific spreader. African Feather Grass thrives in pastures, roadside, wasteland and urban areas. New colonies will arise from moved or broken root systems and form dense clumps which out-compete desired vegetation.
Senegal Tea
Gymnocoronsis spilanthoides
Usually restricted to marshy soils and still or slow-flowing water, which allows the plant to grow up to 1.5 m tall and creates a floating mat, extending from the margins of the water body.
Alligator Weed
Alternanthera philoxeroides
Forms dense mats of vegetation up to 2 m tall. It has a wide habitat range, capable of growing on saline and estuarine environments to relatively dry pastures.
Noogoora Bur
Xanthium strumarium
Fast growing summer annual – is a single stemmed plant amongst crops(maize) or a bushy plant in the open up to 2m tall. Spreads rapidly by attaching to animals, clothing or machinery. Fruit are egg shaped burs, 10-25mm long covered in hooked spines with 2 stout straight spines at the tip, in clusters on the stems and at tips of branches.
The plant is toxic to stock, can devalue wool and will out-compete pastures and crops.
What can be done?
- Learn to identify key pest plant species and what you can do to minimise the spread.
- Visually inspect all machinery used on site for organic matter, even small soil samples may contain seed, root or crown fragments.
- Ensure all tyres, tracks, undersides, grills and filters, and other machinery or equipment that has been used around the lake edge, rivers, streams, wetlands and drainage sites are thoroughly cleaned before leaving the site, and prior to entering new environments.
- Contractors may establish weed management plans to minimise the spread of pest plants in the Bay of Plenty Region.
- If you are concerned about identification of a plant, or if you wish to report an infestation, notify Bay of Plenty Regional Council on 0800 884 880.