News & Media

Home gardeners look out for citrus gall wasp

Released on

Released on:
Friday, 7. May 2021 - 10:15

The Department of Primary Industries and Regional Development and industry group WA Citrus are appealing to gardeners, especially those in citrus production areas, to inspect their trees and implement control measures to reduce the threat to their tree’s health and the WA citrus industry.

Citrus gall wasp can damage citrus trees by forming distinctive galls on stems, which look like woody bulges up to 250 mm long and 25 mm thick. The galls weaken branches, eventually making them unproductive if left unmanaged.

WA Citrus biosecurity representative Helen Newman said residents living in or near citrus growing areas, from Moora/Dandaragan down to Manjimup, and in isolated regions such as Carnarvon and Kununurra should take steps now to help protect orchards.

“Now is a good time to check trees and remove galls before the cool weather sets in,” Ms Newman said.

“The wasps lay eggs in branches from September to December, and galls become visible from February.

“In the southern region, it may take longer for galls to become visible as they are slower growing in colder areas, therefore it is important to check trees in winter and again in spring to ensure none have been missed.

“Purchasing and moving trees during the spring-summer period can be particularly risky for spreading the pest unknowingly as the galls are not visible from eggs laid in spring.”

Ms Newman said pruning out gall-affected branches was essential for controlling citrus gall wasp.

“For Perth gardeners, working with your neighbours to manage gall wasp in your area will have the most success.

“If all citrus tree owners check and treat their trees, it should help prevent a wasp reinfestation in following seasons,” she said.

DPIRD research scientist Rachelle Johnstone said it’s best to remove galls before 30 June and dry them out in the sun before placing in green waste or verge collection.

“Galls removed after 30 June need to be treated before disposal to ensure larvae do not survive,” Ms Johnstone said.

“Galls can be treated by shredding or mulching, or ‘solarised’ by placing them in a well-sealed plastic bag and left in the sun for at least four weeks.

“Home gardeners in the metropolitan and regional areas are reminded to pay close attention to their trees and report suspect detections so DPIRD can keep track of the spread of the pest.”

To report the presence of citrus gall wasp, send a photo and your suburb using the department’s MyPestGuideTM Reporter app or contact the Pest and Disease Information Service on 9368 3080, padis@dpird.wa.gov.au

Further information on citrus gall wasp control is available on the department’s website at www.agric.wa.gov.au/plant-biosecurity/citrus-gall-wasp-control

Citrus gall wasp forms distinctive galls on stems, which look like woody bulges up to 250 mm long and 25 mm thick. Gardeners are being urged to prune and treat infested trees now.
Citrus gall wasp forms distinctive galls on stems, which look like woody bulges up to 250 mm long and 25 mm thick. Gardeners are being urged to prune and treat infested trees now.

Media contact: Megan Broad/Donna Coleman media liaison   +61 (0)8 9368 3937