Field dodder: report sightings of this pest vine

A 2018 import of berseem clover seed to New Zealand contained a small amount of 6 other plant species including a pest vine called field dodder. We need your help to check if the vine is growing in any clover pasture.

How field dodder got to NZ

A quantity of berseem clover seed (Trifolium alexandrinum) imported in late 2018 has been found to contain seeds of 6 other plant species.

One of these other species – field dodder (Cuscuta pedicellata) – is not approved to enter New Zealand. It is a moderate biosecurity risk. But there is a low likelihood that it will establish here.

What's being done about the pest vine?

As a precaution, all the berseem clover seed is being traced and resulting crops checked for any sign of field dodder. Most of the berseem clover seed containing other seeds has been destroyed. Biosecurity New Zealand is working with those who bought it and the grain industry to find and destroy the rest.

Biosecurity New Zealand has done tracing and monitoring and has considered possible options if any field dodder germinates and grows.

The risk to NZ from the unwanted seeds

Field dodder is not currently present in New Zealand. It is a moderate biosecurity risk. There is a low likelihood that it will become established here.

The other 5 species in the berseem clover seed are already present in New Zealand. Their biosecurity risk is low.

If any of the berseem clover seed has been further mixed with other seed mixes, its biosecurity risk is low and it can be planted. The crops should still be monitored for any sign of germinating field dodder.

How to identify field dodder

Field dodder is an annual parasitic vine with many thin yellow/orange branches that wind around its host in a dense tangle. It draws water and nutrients from its host through numerous small penetration organs called haustoria.

The host will lose hair from its stems and have its leaves reduced to tiny scales.

Herbicides are usually ineffective against field dodder.

Field dodder images side by side
Images courtesy of Assoc. Prof Irum Muktar (Minjiang University)
Field dodder close up capture
Image courtesy of Dr Mohammad Shahid (International Center for Biosaline Agriculture)

What to do if you find it

If you see any field dodder amongst berseem clover pasture:

  • take a photo
  • collect a sample
  • record the location
  • freephone our pest and disease hotline – 0800 80 99 66.

Who to contact

If you have questions about the information on this page, email info@mpi.govt.nz

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