Home gardeners in regional areas are being urged to check their citrus trees for unusual woody growths following the recent detection of citrus gall wasp on a tree in Geraldton.
The Department of Primary Industries and Regional Development (DPIRD) 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 millimetres 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.
DPIRD research scientist Rachelle Johnstone said it was best to remove galls before June 30 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 shedding 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 MyPestGuide Reporter app or contact the Pest and Disease Information Service on 9368 3080, padis@dpird.wa.gov.au.