Out of Africa, possible cure for local weed problem

News release | 17-Oct-2018

There could be a breakthrough in the quest to find a biological control for the aggressive Navua sedge weed affecting pastures throughout Far North Queensland after a Queensland Government-led study to Eastern Africa.

Biosecurity Queensland Principal Entomologist Dr Kunjithapatham Dhileepan recently travelled to Africa to assess dozens of species of sedge and pinpointed a type of fungus as a possible treatment to fight the weed.

Navua sedge is an extremely aggressive weed affecting the beef, dairy and sugarcane industries in Queensland’s wet tropics.

“More than 500 beef producers, dairy farmers, crop and hay producers in the Atherton Tableland region alone are affected by the weed,” Dr Dhileepan said.

“It grows in thickets and replaces palatable tropical pasture species. Finding a natural enemy will be a significant benefit for Queensland’s agriculture industry.

“As part of the study, I looked at 36 sedge species at 75 sites in Kenya and Tanzania in partnership with research collaborators from the East African Herbarium, the National Herbarium of Tanzania and the University of Southern Queensland.

“We found a new species of fungal (smut) pathogen that attacks Navua sedge’s flower head and seeds. If further studies confirm that this fungus will only damage Navua sedge we’ll be seeking approval for its release in Australia.

“Future surveys are planned in West Africa to hopefully find even more useful pathogens.”

Dr Dhileepan said Biosecurity Queensland funded the African study in response to demand from industry for biological control agents for Navua sedge.

“Current management options for Navua sedge are mechanical and chemical, which are expensive and offer only provide short-term results,” he said.

“Biological control options are considered to be the most cost effective and long-term management option.”

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Media contact: DAF Media, media@daf.qld.gov.au