What would you do if South American weeds were blocking your local Australian waterways? In the case of the cabomba plant, scientists are enlisting the help of the weed’s natural enemy, the tiny South American cabomba weevil.
Cabomber (cabomba caroliniana) originally came to Australia as an aquarium plant in 1967 and has since spread throughout the lakes and rivers along the country’s east coast. It grows up to 5 cm (2 inches) per day and forms clumps that displace local flora and fauna, block sunlight from reaching deeper depths, increase the cost of water treatment, and make it impossible. If not, it makes boating and other recreational activities difficult.
Large amounts of weeds are currently removed from water bodies by mechanical means, but doing so is an expensive and laborious process, and vegetation quickly returns to problematic levels. Putting it this way, scientists at the Australian National Science Organization CSIRO found that the Kabomba weevil (swimmer afraid of water).
Native to several South American countries, this aquatic insect gets its name from the fact that it is only about the size of a grain of rice and eats nothing but kabomba.
That said, to ensure safety, CSIRO scientists raised three generations of weevils in captivity and provided 17 Australian aquatic plants closely related to cabomba. The weevils showed no interest in other plants and ate only cabomba throughout their lives.
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Imported weevils batches were initially isolated and individually tested for parasites and pathogens. After passing that test, they were bred in captivity and produced a recently released population in Kabomba-infested Lake Kruwomba, north of Brisbane.
Only time will tell how effective insects are at controlling weeds. Meanwhile, many of the weevils are bred for use in other lakes.
The project is funded by the water company Seqwater and the Australian Government Ministry of Agriculture, Forestry and Fisheries. The research is led by Dr. Kumaran Nagalingam of CSIRO and Dr. David Roberts of Seqwater.
Source: CSIRO
