Bio solution for pasture pest

Irrigated lucerne growers in the Tamworth, Mudgee, Riverina and Hunter regions could soon have a safe biological solution to a major lucerne pest.

NSW Department of Primary Industries entomologist, Adrian Nicholas, solved an international dilemma, finding whitefringed weevil larvae were the culprits responsible for chewing holes in some subsurface drip irrigation pipes.

Now Dr Nicholas is researching a biological control for the whitefringed weevil.

"Weevil larvae burrow into the soil where they cause damage to lucerne plants by feeding on their roots," Dr Nicholas said.

"While they’re down there, they chew through subsurface pipes, making extra holes which reduce the efficiency of irrigation systems and create a costly repair problem
for farmers."

A laboratory observation chamber is being used to work out why weevil larvae chew plastic pipe.

"They may think that it’s a food source, they may be after water in the pipe or maybe they’re attracted to the plastic itself," Dr Nicholas said.

Once researchers have that answer, the next step will be to find a safe biological control which, they say, will protect both the pipe and lucerne plant.

"We should be able to control the larvae and that will prevent them from chewing lucerne roots, and will increase the longevity of the plants and productivity for growers," he said.

Farm trials are planned to test whether the pipes can be used as a distribution system for the new biological control.