Scientist’s study of pest life cycles contributes to Queensland fruit fly eradication

Specialist AgResearch expertise in population dynamics was used by MPI to assist eradicate the Queensland fruit fly from Grey Lynn in 2015.

“This was the fourth Queensland fruit fly detection in the last three years, and the only event which involved an establishing population,” says AgResearch population ecologist John Kean.

John has been a regular contributor of advice to MPI over the years for a variety of incursion events.

“Starting with painted apple moth over a decade ago, I have been using my skills in population dynamics to help the Ministry for Primary Industries (MPI) answer a range of questions that crop up during eradication programmes. Queensland fruit fly was one of over a dozen eradication programmes I have been involved in.

“I have also done a lot of work to assist with developing improved understand of the efficacy of the trapping grids used for early detection of Queensland fruit fly and how this might be increased.  For the eradication in 2015 input was provided to assist MPI with predicting development rates and the likely time of introduction, the life stages that might be expected at different times, and winter mortality.”

John’s research also supported MPI in concluding the programme and declaring achievement of eradication.

In recent years Queensland fruit fly developed to epidemic proportions in parts of eastern Australia, which included invasion into areas operating area freedom programmes for fruit production. It’s always been a problem for Australian growers and home gardeners, and recent withdrawal of two insecticides from use together with some unusual weather events has resulted in an increased pest management challenge.

“This is an insect best suited to the tropical/sub-tropical climate of northern New South Wales and southern Queensland, and it is robust enough to survive under cooler conditions,” says John.

“For New Zealand this means that the most ideal climate for the fly is probably Northland and Auckland, and that together with the concentration of international traffic is why most of the 3,500 fruit fly trapping sites are located there. For those of us further south the climate is marginal for Queensland fruit fly, but MPI operates surveillance traps nation-wide to demonstrate on-going country freedom.”

The threat of further incursions continues and is likely to grow with increased tourism and trade, so ongoing vigilance through the trapping network is required.

“Strong media interest in fruit fly detections, has contributed to making the New Zealand public more aware about biosecurity and its importance” says John.

“Understanding that one small piece of fruit brought back to New Zealand in luggage could harbour a pest that would decimate New Zealand horticulture exports is very helpful for getting people to make sure they are risk-free and contribute to maintaining the security of our borders.”