Bunbury gardeners urged to be alert for citrus pest

South West green thumbs have been urged to check their citrus trees for a destructive pest before moving them, after a citrus gall wasp was recently found in a plant at a Bunbury nursery. The Department of Primary Industries and Regional Development and industry group WA Citrus have also recommended Bunbury residents who have recently bought a citrus tree to check it for the pest. Citrus gall wasps damage trees by producing galls — which look like woody bulges — that weaken the branches, and gardeners are being encouraged to prune the branches before relocating their trees to avoid the risk of spreading the pest to commercial orchards. Galls are most visible at this time of year, making infested trees easier to spot, according to WA Citrus biosecurity representative Helen Newman. “We remind people to check citrus trees for galls, and prune as needed, before they move them — any infested material must be treated,” Ms Newman said. Ms Newman said moving trees during the spring-summer period was risky because the pest was often hard to see and could unknowingly be spread. Gardeners have been encouraged to check their trees and take necessary measures, before the wasp starts emerging next month. “Each wasp lays up to 100 eggs so pruning heavily infested trees and correctly disposing of infested material will stop thousands of wasps emerging and spreading,” Ms Newman said. Those pruning their trees need to treat the material before disposal otherwise wasps could still emerge, DPIRD research scientist Rachelle Johnstone warned. “If people are unable to prune now, horticultural glue can be used on the galls to trap and kill the wasps as they emerge.”