Optimal Conditions
Lemon trees in temperate to sub-tropical conditions
Signature
Swellings or ‘gall’ on the limbs of the citrus plant.
Prevention
Such is the migratory nature of gall wasps that unless we all pruned and rid our trees of every single wasp at exactly the same time, they will inevitably strike back. But measures to reduce infestation include hanging sticky yellow traps and avoiding over-fertilising our plants in early spring, as the young delicate stem growth is the ideal breeding ground for its eggs.
Coping
Seasonal pruning and discarding of the affected limbs, making sure not to put unhatched galls in the compost. If you can't see pin head sized exit holes on the gall, there are still unhatched eggs inside it. Best to dispose in the bin or burn these limbs
Eradicating
Nearly impossible. Regular management is the only measure and it is another pest we have learned to live with.
