Biocontrol using Cochineal Bugs
Biocontrol using Cochineal Bugs
Using insects to control Wheel Cactus in the Western Region
Collaborations -
Ref LP045-23
The issue
Combine a few good rain seasons and the Emu’s taste for the sweet fruit of the prickly pear, has seen an explosion of wheel cactuses in river country near Menindee. The cactus originally escaped from house gardens and has increased in numbers. They now cover almost 120ha. When recent riparian restoration works were being planned the cactus were identified as a threat to native plants and due to their proximity to the river and its fragile ecosystem, an alternative to chemical control was investigated.
The solution
The humble cochineal beetle was identified as an effective biological control agent for prickly pear. The original cochineal insects, and prickly pear plants, were brought to Australia on the First Fleet to start a cochineal dye industry. Varieties of cochineal insects look the same, but they are not, and will only thrive on their own, specific host plant.
Cochineal attach to the outside of the host plant and feed on the sap, effectively sucking the plant dry and killing it!
The impact
Western LLS has various colonies around the region and we were able to source the right variety for the Wheel Cactus infestation at Menindee. While the cochineal insects are very effective it will take them a while to establish enough numbers to start to be effective before we start to see a dramatic decrease in cactus population. This site will now be used as another breeding centre for this variety of Cochineal that will be used in other sites once it is established.
Key facts
- Biocontrol = natural enemies of a target weed
- Cochineal insects can be blown long distances by wind