This study shows the impact of a small incursion of a pest fruit fly species in one of our horticultural districts would be substantial.

Mediterranean fruit fly, also called medfly and scientifically Ceratitis capitata is one of the most destructive pests known. It is considered able to infest most of the temperate and subtropical parts of the world. It has a wide host range, including many types of fruit, vegetable, ornamental and weed species grown in New Zealand. The life cycle is rapid and the breeding prolific. A single infested fruit can be the origin of a new infestation.

Exports of horticultural produce from New Zealand earned $2.3 billion in 2005. Over 90% of fresh fruit and vegetable exports by value are of produce that could host medfly.

A small incursion of medfly was found in Auckland in May 1996 via routine checking of monitoring traps. The Ministry of Agriculture and Forestry (MAF) successfully eradicated the pest. Export markets imposed restrictions on New Zealand produce from the Auckland area which lasted 8-12 months or longer.

This study was prepared to find the likely cost should such an incursion have occurred in a major fruit growing district. It follows on from a similar study in 1998 which modelled the impact of an incursion in the Bay of Plenty.

The market restrictions applied to the Auckland incursion were modelled as if the incursion occurred in one of the three major fruit growing districts of the Bay of Plenty, Hawkes Bay or Nelson. The timing is for the incursion to be found just before harvest. Market restrictions are modelled to occur for 12 months for a 15km radius zone. Fresh fruit fly host produce from this zone is excluded from export markets except Europe and Western Australia, which have medfly and imposed no restrictions in 1996.

The ability to export produce from the incursion zone to European Union markets provides significant mitigation of the impacts, particularly for the major crops of apples and kiwifruit.

Disrupting market plans would cause loss of revenue. Additional costs would occur for insect proofing, packaging changes, transport and adjustments to shipping programmes, for export, domestic and processing crops. Re-assigning produce to packhouses and markets, depending on whether the orchard was inside or beyond the incursion zone, would create significant logistical challenges and stress on top of the usual stresses of harvest.

Access the PDF of the report here: Fruit Fly Final Report 2007