At sites where the flies are well established, seed production has declined dramatically and in some cases has virtually ceased, with only large bunches of galls evident on the trees, where seed pods once hung in abundance […].
Although this reduction in seeding will not cause an immediate decline in the density of existing thickets of black wattle, it will curb the invasiveness and rate of spread of the plants and thereby prevent the problem from escalating further. This will buy time while other control operations deal with the existing thickets and persistent and expansive bank of soil-stored seeds which typify black wattle and many other invasive tree species.
Tiny gall fly has a big impact on invasive black wattle, John Hoffmann
In Portugal, a biological control agent is being studied for the Sydney golden wattle (Acacia longifolia): Trichilogaster acaciaelongifoliae, a small Australian gall-forming wasp. The results obtained in these tests have led to the request for its release, and today the process is being analysed by the relevant authorities.
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