Nun moth

Lymantria monacha

With a taste for conifer trees, the nun moth could pose problems for our forestry industry. During an outbreak, the caterpillar can strip a pine tree, stunting its growth or even killing it.

About the nun moth

The nun moth is related to the gypsy moth and painted apple moth. Unlike these species, its main hosts are conifer species, like pine, spruce, larch, and fir trees. It's native to Asia and Europe. Its range extends from Japan to Portugal.

The caterpillars can strip a tree of all its needles or leaves, which reduces the tree's growth. During an outbreak, caterpillars can kill trees. Over the last few decades, the frequency of outbreaks has increased.

Global distribution of the nun moth

World map showing distribution of nun moth.

Why this is a problem for New Zealand

We know the nun moth has a range of host trees. From scientific experiments done in America, we know the nun moth grows well when eating radiata pines. Our forestry industry could face serious problems if this moth established in New Zealand.

Map of New Zealand showing where the nun moth could establish

How it could get here

The female moths can lay between 70 and 300 eggs in many small clusters. They mostly lay their eggs in cracks and crevices, like in bark on trees and on fence posts. (We don't allow bark into the country unless it been thoroughly treated).

Whenever travelling to New Zealand, always declare any wooden products in your luggage. If you fail to do so, you could face a $400 fine.

When and where to watch for it

The nun moth is most likely to arrive in New Zealand after an outbreak overseas. Although the moth lays its eggs in summer, they don't hatch until the following spring.

The caterpillars blend in well on a conifer branch. If you find a hairy caterpillar camouflaged on a conifer tree, call us.

How to identify the nun moth and its caterpillar

Hairy caterpillar with small spots down its back
Nun moth caterpillar. Image: Creative Commons by Hectonichus

The caterpillars are hairy, brown, and found on conifers. They start out about 0.5cm long and are up to 4cm long in their later life stages (instars).

Adult nun moth. Image: Creative Commons by Lukas Jonaitis

The adult moths can range from light to dark. Their forewings are usually banded with black and are quite striking. They only live about a week.

Their wingspan is 4cm to 5cm.

If you think you've found it

The hairs on a nun moth caterpillar aren't known to cause irritation, but you should be careful handling any hairy caterpillars. Some species can cause an itchy or painful rash.

 


Note: This information is a summary of the nun moth's global distribution and potential impacts on New Zealand. 

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