Citrus gall wasp
Adult citrus gall wasps are rarely seen as they less than 3mm in size. The adults are poor flyers but can be windblown from other citrus trees nearby. The adult wasps mate in early to late spring when the female implants her eggs in the citrus tree that she herself emerged from just days before. Often the larvae are already present in newly purchased citrus trees in spring. The wasp larvae grow within the soft stem tissue for 9 to 12 months until they too pupate and emerge as adult wasps the following year.
Damage: The wasp larvae grow within the citrus stems until late summer when gardeners start to notice unsightly galls appearing on their trees. These galls or calluses are formed in response to the presence of the feeding larvae. Galls cannot be ‘cured’ or reversed. Old galls are unsightly but are also empty as the adult wasp will have left through the tiny exit holes. Developing galls can be removed but this may also mean the loss of developing fruit at the end of the infected stem. Citrus gall is more damaging to younger citrus trees than older trees.