Passionvine hoppers, also known as fluffy bums, have been in New Zealand since the 1800s but this summer they are everywhere.
At the Greymouth Nursery, John Phillips said it seemed every second phone call was about the airborne invasion.
"And not only on plants, they are on clothes too, the clothesline ... "
The pest was normally only seen in small numbers but this year, with different weather, their numbers had exploded.
For those whose gardens are under attack Mr Phillips recommended using insecticide, such as Mavrik or Success.
However, he urged caution over what insecticide to use in the vegetable garden.
While the insecticide might not eliminate the pest, it should help control numbers.
"It will pass in time ... they are busy laying their eggs for next year."
Landcare Research told the Greymouth Star "These are not moths, our moth expert says, they are homopteran sap-sucking insects. They are a well-established pest."
They have been in New Zealand since at least the 1880s and are also known in Nelson and Marlborough.
Landcare Research said the good weather on the West Coast would not have much difference to their numbers, but "we can’t answer that question definitively without research being done".
Hoppers can be found on herbaceous plants, shrubs and trees — the list is huge, but includes ferns and cabbage trees, pumpkin, sunflower, hydrangea, privet, eucalypt, privet and even cutty grass. As they feed on the plants they produce honeydew which makes the plants sticky and black from sooty moulds.
