Clever cochineal culls crippling cactus

A tiny insect has saved a weed-infested paddock north of Eulo by controlling a coral cactus infestation.

Minister for Agricultural Industry Development and Fisheries Mark Furner said the biological control agent, cochineal Dactylopius tomentosus, was released to tackle what had been described as possibly the worst coral cactus infestation in Queensland.

“Biosecurity Queensland officers released the cochineal insect in February 2017 in a very large and dense infestation of coral cactus at Moama Station, north of Eulo,” Mr Furner said.

“A visit to the site in November 2018 found that almost all coral cactus plants within a 120 hectare paddock had been completely killed and that the insect had spread onto scattered coral cactus plants several hundred metres away from the core infestation.

“This fantastic result, which allows the land to be used productively again, mirrors outcomes at numerous other sites, including Longreach and Hebel, where the insect had controlled coral cactus within 21 months.”

Mr Furner said research had shown that one population of the cochineal Dactylopius tomentosus was found to be particularly effective against coral cactus.

“The cochineal was approved for release in Australia in 2016, following testing that showed the insect did not feed or attack other plant species,” Mr Furner said.

“Subsequently, the insect was released at numerous sites around the state including Barcaldine, Richmond, Moama, Wyandra and Thargomindah as well as in Western Australia and South Australia.

“Results from the trial sites provide hope for land managers across Australia that the insect is a useful tool to manage coral cactus.”

Mr Furner said coral cactus was one of eight Cylindropuntia cactus species targeted for biological control by Biosecurity Queensland.

“All eight species were introduced as ornamentals and have since escaped gardens and become major weeds impacting on agriculture and the environment,” Mr Furner said.

“Of particular concern, is that these cactus species have very sharp barbed spines which can impale and immobilize small animals and prevent larger stock from eating, resulting in a painful death.

“An important aspect of the research showed that different populations of the cochineal attack different species of Cylindropuntia cactus which allows for more effective targeting of infestations.”

Follow Biosecurity Queensland on Facebook and Twitter (@BiosecurityQld)

/Public Release.View in full here.