News & Media

September reminder to prune trees to remove citrus pest

Released on

Released on:
Thursday, 12. September 2019 - 12:00

The damaging pest citrus gall wasp will soon be emerging from its nests, prompting a reminder to Perth gardeners to check and prune infested citrus trees this month.

The Department of Primary Industries and Regional Development and WA Citrus are encouraging residents, particularly in the suburbs of Morley, Dianella, Eden Hill, Lockridge, Bayswater and Bassendean, to be vigilant for the pest.

WA Citrus biosecurity representative Helen Newman said citrus tree owners needed to implement control measures on their property to limit spread of the destructive wasp.

“We have recently seen some significant infestations of citrus gall wasp in backyard trees,” Ms Newman said.

“Citrus gall wasp forms distinctive galls on stems which look like woody bulges up to 250 mm long and 25 mm thick.

“The best way to treat heavily infested trees at this time of year is to prune them.

“Citrus trees will recover from a hard prune and your tree will produce a healthy crop the following year.

“Pruning of infested trees has to be done soon, as wasps begin emerging from the galls in late September.

“Each wasp lays up to 100 eggs so pruning heavily infested trees will stop thousands of wasps emerging and spreading.”

Galls and removed plant material should be shredded and solarised, burnt or deep buried.

Ms Newman also reminded residents to limit movement of citrus plants in order to avoid spreading the pest.

“From late September to April, signs of infestation can be hard to see, so if moving a potted citrus tree during this time, prune before you move. Check again in April for galls and prune if necessary,” she said.

It follows a recent report of an infested potted tree being moved 25km north-west from Beechboro to Carramar, closer to commercial orchards.

Further information on citrus gall wasp control is available on the department website.

Anyone wanting to submit photos to check for this pest, or report the presence of citrus gall wasp at their property can report it using the department’s MyPestGuideTM Reporter app (choose the ‘Citrus gall wasp’ project) or to the Pest and Disease Information Service on (08) 9368 3080, padis@dpird.wa.gov.au

Before and after images of a citrus tree infested with citrus gall wasp
Before and after images of a citrus tree infested with citrus gall wasp, which was pruned heavily in August 2018. The tree, pictured in September 2019, is now free of citrus gall wasp, is flowering and will produce fruit soon.
Before and after images of a citrus tree infested with citrus gall wasp
Before and after images of a citrus tree infested with citrus gall wasp, which was pruned heavily in August 2018. The tree, pictured in September 2019, is now free of citrus gall wasp, is flowering and will produce fruit soon.
Citrus tree infested with citrus gall wasp
A citrus tree infested with citrus gall wasp.

Media contacts:

Jodie Thomson, DPIRD media liaison           +61 (0)8 9368 3937