Frequently Asked Questions

Could didymo spread to lakes throughout New Zealand?

Yes. Although didymo prefers a river environment with clear water flowing over stable substrate at depths sufficient for light penetration to drive photosynthesis, blooms have been found in South Island Lakes. Lake Wakatipu, for example, contains visible didymo on some parts of the lake shore.

What other pests are likely to invade waterways?

Aquatic weeds like Hydrilla, Hornwort, Salvinia and Lagarosiphon.

For Taiwan - can you plant before pre-plant survey results are known?

Yes, at the grower’s risk. If PCN is found the production site will be removed from the programme.

What are the main symptoms of avian influenza?

The main symptoms to look for in poultry are:

  • Sudden and unexpected deaths
  • Rapid spread of disease throughout the flock
  • Depression and loss of appetite
  • A drop in egg production
  • Nervous signs such as unusual head or neck posture, convulsions
  • Swelling and blue combs and wattles
  • Coughing, sneezing and diarrhoea
What is Tuber brumale (Winter Truffle)?

It is an edible truffle which is associated with oak and hazel trees. It occurs naturally in France and Italy and in other parts of Europe.

What will happen to me if I am caught carrying fruit in the restricted area?

You are allowed to carry fruit within the wider zone but not allowed to remove it from the area. If you live in the inner Zone A, you should not take whole fruit and veges from your house at all. The Ministry does have the power to stop you.

What does Gum leaf skeletoniser look like?

Gum leaf skeletoniser goes through four different life stages, each looking very different from the other:

Gum Leaf Skeletoniser Moth

  • Eggs are about 1 mm in diameter and are laid in groups of 100 to 200 in parallel rows on young leaves. The eggs are yellow-green at first and turn brown as they develop.
  • Caterpillars are hairy and coloured pale yellow with black and grey markings. Older caterpillars have a distinctive 'hat' on their heads.
  • Cocoons are usually formed under bark or in leaf litter and are rarely seen.
  • Moths are dull grey with silver-grey forewings and a wingspan of 20-30mm.

Two gum leaf skeletoniser life cycles are completed each year, one in summer and one in winter. For more information on the biology of this insect, see the Uraba lugens Factsheet Link to PDF document (181 KB).

How did didymo get into the New Zealand river system?

We will most likely never be able to determine exactly how didymo first entered the river system. The most plausible method of introduction was the unintentional transport of microscopic didymo on recreational or industrial equipment from affected areas overseas. DNA evidence suggested didymo was introduced from North America on fishing equipment.  

My business has lots of daily foot traffic. Do I need to maintain a visitors record?

Depending on the facility and if risk goods are present:

If a facility is able to control access (eg customer and couriers are coming to one area to pick-up and drop-off items) then a visitors book might not be necessary.

In general, there should be no public access where uncleared risk goods are held.

Why do I have to clean items that have been in contact with water between EVERY river?

Didymo is hard to detect in its microscopic form, so it is invisible in some waterways. People need to treat all waterways as if they might have didymo. People need to Check, Clean, Dry everytime they use a waterway.