At least 15 years ago, we became aware of the failure of lantana to recolonise areas at Eurong where we had removed it. We then started to observe the thinning out of the lantana in the bush. As we examined ailing lantana bushes we observed saw leaves with rust, leaves with leaf miners and leaves that had been attacked by insects chewing them up.
Biological control of lantana is a long-term control option and has had mixed results. The objective is to reduce plant viability and prevent its further spread by stressing plants and reducing seeding processes. In some cases, it has resulted in die-back of the lantana plants.
Since 1914, 31 biological control agents have been introduced to Australia to try to control lantana. Seventeen have established, with several insect species causing seasonal damage, reducing the vigour and competitiveness of lantana in some areas. Of these 5 are bugs, 5 are moths, 4 are beetles and 3 are flies. In addition, rust is now also working.
Establishing biological control for lantana has been made difficult because Australia’s lantana is comprised of several hybrid cultivars that don’t exist in the native Central American habitat. Another obstacle in many areas is that the climate, especially cold winters knock back the populations of some insects. Some populations have been wiped out while it takes time for populations to rebuild when the weather warms up. Luckily enough predators seem to thrive in the more equitable weather on K’gari that is helping to control and reduce Lantana.
FIDO’s Happy Valley volunteer groups working in Happy Valley are now so confident of the impact of the biological control based on their observations, that they have dropped the priority of Lantana as a pest weed in Happy Valley. This is further evidence that biological control is working.
The biological control is working around Eurong where these weeds are more spaced out although is making little dent on the larger thickets. It is for this reason that FIDO has initiated “Lantana Attacks” to thin out the thickest lantana and give the biological agents more opportunity to work.
Article contributed by John Sinclair, FIDO