REPORTS of citrus gall wasps in Kalamunda have been recorded by DPIRD with the end of June marking an important deadline for residents to control the pest.

Citrus gall wasps can damage citrus plants and reduce fruit productivity as the bumpy and nodular growths they cause disrupt water and nutrient flow in trees.

Any galls pruned before June 30 can be disposed of in green waste, but galls pruned after this date should be treated to ensure the wasp does not emerge from the pruned gall.

Prunings made before June 30 will ensure the developing wasps die inside the galls as the pruning dries out, but galls pruned after that date must be solarised by sealing them in plastic and placing them in the sun.

WA Citrus biosecurity representative Helen Newman said it was expected the populations were growing and spreading throughout Kalamunda following reports of the pest in the area.

“We no longer collect reports on citrus gall wasps from the metropolitan area, as it is considered an established pest,” she said.

“Our focus is now on keeping this pest out of regional towns near commercial citrus orchards

“The wasp doesn’t fly well, so it usually spreads to other nearby trees when egg-laying space on the infested tree is limited.

“It can, however, be carried on the prevailing wind like the strong easterlies, which will further its spread.

“If there is uncontrolled citrus gall wasp in an area, it is likely that it will establish quickly.

“If managed well, residents will be able to enjoy productive citrus trees for many years to come.

“Once citrus gall wasp becomes established in an area, it is difficult to manage and is an ongoing battle for home gardeners.”

According to a WA Citrus fact sheet, citrus gall wasps have one life cycle each year, laying up to 100 eggs under bark of new green shoots, which hatch in two to four weeks.

The larvae then burrow into plant stem, causing the woody galls from which they emerge as adults in spring.

Wasps emerge from September to December, living three to seven days as adults during which time they are very difficult to control.

“You must work with your neighbours to successfully manage the pest,” Ms Newman said.

Citrus gall wasps may be reported to the MyPestGuide Reporter app or biosecurity@wacitrus.com.au