A team of researchers at the Tasmanian Institute of Agriculture (TIA) are using 2500 wasps imported from Chile as their latest weapon as they continue attempts to manage a major pest to the apple industry, codling moth.
Codling moth is one of the most economically damaging pests of apples. In an unmanaged orchard the major pest can wipe out 50 to 90 per cent of the fruit, decimating the crop.
Codling moth also infect quince, pear, nashi, summer fruit, walnuts and chestnuts which if left unmanaged, can reinfest nearby apple orchards.
A research team including TIA Entomologist Dr Jon Finch recently released the wasp species Mastrus ridens at an apple orchard in the Huon Valley. It's part of the national PIPS 4 Profit program, funded by Hort Innovation using the apple and pear research development levy. The Pest and Disease Management component is a collaboration with partners at Agriculture Victoria, and several other regional partners across Australia.
Mastrus ridens is a parasitic wasp species that targets codling moth. As both originate from central Asia, Mastrus is a highly specialised natural enemy.
"The wasp specifically targets codling moth larvae by laying its eggs inside them, reducing the moth population naturally without the need for chemical pesticides," Dr Finch said.
"The wasp will seek out hibernating codling moth caterpillars and lays eggs in the cocoons. When the wasp eggs hatch the wasp larvae feed on the codling moth caterpillars, killing them."
Dr Finch said that by introducing Mastrus ridens into apple orchards, growers can decrease reliance on insecticides, leading to more sustainable and environmentally friendly pest management.
"The use of parasitic wasps helps prevent economic losses caused by codling moth infestations, which can cause significant fruit damage and lower apple quality," he said.
It's the latest effort to establish the species in Tasmania. They were previously released in the Huon Valley and researchers believe they had a significant impact on codling moth populations during each release year.
"Unfortunately, the wasps failed to establish a permanent population, possibly due to inbreeding in earlier lab populations imported into Australia," Dr Finch said.
"We're confident that this new importation of the parasitic wasp from our Chilean research partners will establish successfully."
The project will be ongoing for two to three years and researchers plan to move the wasps to other areas of the state that are battling codling moth.
Dr Finch said there's no biosecurity implications from importing the wasps.
"The species has undergone extensive testing to ensure it does not pose a risk to native insects or animals."
"This involved exposing Australian native insects to the new wasps to determine if they will attack them or not.
"The results showed that the wasps only attacked codling moths. Because of this we are very confident that the wasps are safe for the environment."
It's one of a number of projects TIA has undertaken to manage the major pest in recent years.
Researchers also partnered with local apple growers to pilot a controlled sterile insect release program that finished 18 months ago.
