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Trapping programme keeping Tairawhiti free from gypsy moths

SMALL green boxes have popped up on trees around the city, leading sharp-eyed locals to question their purpose.

The boxes are insect traps, which use secreted or excreted pheromones to lure other insects, in this case gypsy moths (Lymantria dispar).

“The gypsy moth surveillance programme (GMSP) conducts seasonal monitoring with pheromone traps placed on favoured hosts at locations considered to be high risk for the entry of gypsy moth, such as around international seaports and import sea container depots,” the Ministry for Primary Industries said.

About 30 of these traps have been placed around Gisborne.

GMSP runs annually from October to April, with more than 1500 traps placed around the country.

With an increase in trade such as incoming containers and cars from Asia, there is also a risk of pest interference.

The GMSP was developed in 1992 to provide early warning of incursions to enable eradication and provide verifiable evidence that New Zealand is free of this pest.

The programme targets all moth species of the genus Lymantria, including the Asian gypsy moth (Lymantria dispar asiatica) and the European gypsy moth (Lymantria dispar dispar).

The juvenile insects (larvae) of the gypsy moth can strip trees of their foliage, damaging and exposing them to diseases.

The presence of the gypsy moth in Tairāwhiti — and around Aotearoa — could damage tree species such as pine and apple, generate restrictions on industrial exports, affect garden crops, damage native bush, including the endemic black beech, and impose an economic and ecological burden associated with control and eradication programmes.

Teams placed the traps on potential host trees in a grid pattern designed to cover areas identified as likely points of entry for gypsy moth.

“Based on how strong the lure is, the traps are spaced at about 750 metres to ensure adequate coverage. Traps attract male moths.”

While Aotearoa is considered free from Asian and European gypsy moths, there was an incursion in Hamilton in 2003. After an intensive eradication programme (including aerial treatment) the moth was declared eradicated in 2005.

Any suspect specimens from the trapping programme are sent to Scion, a Crown research industry, for diagnostic identification.

TROUBLESOME PEST: These traps have been placed on trees around the city as part of the annual gypsy moth surveillance programme. Picture by Liam Clayton