A new invader looping across Northern Australia
Northern Territory commercial growers, nurseries, travellers and backyard growers are urged to keep an eye out for a new plant pest that’s been detected in Australia this wet season.
An exotic moth species known as mango shoot looper (MSL) has been officially detected in the Northern Territory.
Increased surveillance has been ongoing since Mango shoot looper (Perixera cf. illepidaria) was detected in Queensland in September 2021, as there are 5 other species of loopers that are found on mangoes in the NT that MSL can be mistaken for.
A specimen submitted from an orchard in the Darwin Rural Area confirmed in early April 2022 that the plant pest is present in the Top End.
Mango shoot looper is an invasive pest from Asia which was detected late last year in the mango production area of Mareeba, Queensland, according to Biosecurity Queensland. It’s the first time the exotic moth has been detected in Australia.
This exotic pest is a threat to both the commercial mango industry, as well as backyard growers and hobbyists. Australian Mango Industry Association (AMIA) states that the Northern Territory contributes to 53.6% of the national mango production annually, closely followed by Queensland and then Western Australia.
Adult MSLs can fly and spread naturally in localised areas from tree to tree. Their spread may be enhanced by strong winds. Female moths are pinkish in colour and the males are very pale brown or pinkish fawn. Males and females have three rows of brown patterns on the wings the last two having dark brown spots interspersed along the length. Their wingspan is about 20 millimetres across.
Larvae which vary in colour from yellow, brown to black with a mottled “tiger” patterned appearance move onto the leaves to feed, when mature they can be up to 22mm in length. Larvae move in a “looping” fashion and can move to undamaged areas of the tree by suspending themselves on silken threads and dropping between branches.
The pupae have a distinctive elongated triangular appearance, they are initially green turning brown as they mature and are up to 9 mm in length. They are likely to be found in old spider webs as well as on the leaves. It is most likely that this pest will be a problem during the flowering season.
MSL may also be spread by human-assisted movement of infested plant material. It is good practice to implement biosecurity measures onto your property, to reduce and prevent biosecurity risks. Information about how to protect your crops can be found at: https://www.farmbiosecurity.com.au/industry/fruit-nuts/
While the MSL does not affect the quality of mature mango or lychee fruit, the pest may reduce yields and cause substantial stress on plants, and even death. In far north Queensland, the moth has been observed causing significant damage on mango plants, which includes totally stripping back flowers and damaging young fruit.
Due to having only been officially detected recently in the Territory, its broader impact, including distribution, is still being investigated. A sample submitted in late March 2022 was confirmed as being Perixera cf. illepidaria in early April 2022. Severe infestations may cause 80-100% leaf and flower damage on affected trees and significant crop losses due to damage to flowers and immature fruit if uncontrolled.
Management options for MSL are available and being communicated to industry as the prevalence of this plant pest is investigated.
The department is working with industry and interstate colleagues to glean information and share knowledge, to be provided at upcoming industry briefings and stakeholder forums.
Adequate control measures at the right stage of pest’s life cycle will keep its damage to minimum. There are existing chemicals that can be used to reduce this pest, along with integrated pest management (IPM) approaches that encourage parasitic wasps and flies to eat MSL at different stages of its life cycle.
These factors will help reduce any potential impact on the Territory’s mango trade, which makes up around half of Australia’s mango production.
There are around 50 commercial mango farms in the greater Darwin region that the department is working with as a priority to help manage this pest.
Additional information about the current management techniques can be found on the Australian Mango Industry Association’s website: https://www.industry.mangoes.net.au/resources/resources-library/mango-shoot-looper/
The Queensland Government also has information on this plant pest available online: Mango shoot looper | Business Queensland
If you suspect a Mango shoot looper infestation, you must report it by phoning the Exotic Plant Pest Hotline on 1800 084 881.
More information
For more general information on on-farm biosecurity measures to implement on your property please contact us on 08 8999 2118 or email plantbiosecurity@nt.gov.au
Additional information about this plant pest in the Northern Territory is available at nt.gov.au/mango-shoot-looper