New biocontrol for damaging weed

By Country News

A bug from Texas and a mite from Argentina could help tackle one of Australia's worst agricultural weeds — silverleaf nightshade.

The two species have damaged silverleaf nightshade in their native countries without harming other plants, and Agriculture Victoria research scientist Raelene Kwong said they offered a promising solution to control the invasive pasture weed.

“The introduction of the lace bug and mite to Australia could save the red meat and grains industries millions of dollars through improved animal health, increased productivity and reduced control costs,” Dr Kwong said.

“Bio-control such as this provides an environmentally-friendly and self-sustaining approach that can reduce the need for costly herbicides, which can damage other crops, lose their effectiveness and are associated with health concerns.”

Silverleaf nightshade is a major problem for meat and grain industries in southern Australia, as it competes with other crops, depletes soil nutrients and is toxic to livestock.

Agriculture Victoria research scientists have undertaken pre-screening trials of the mite in Argentina and field trials of the lace bug are expected to take place in Texas in December.

If successful, they will be imported to the advanced quarantine facilities at the AgriBio Centre for AgriBioscience in Victoria.

There they will undergo screening against closely-related native, ornamental and crop species, with the results submitted to the Federal Government for a detailed import risk analysis.

This research builds on Agriculture Victoria’s biological control successes for pasture weeds, including the use of insects to control Paterson’s curse, which saved millions of dollars for Australia’s livestock industry.

Agriculture Victoria is also leading the Australian component of a new international biocontrol initiative to combat two other major agricultural weeds — serrated tussock and Chilean needle grass.

The research is part of the Federal Government’s Rural Research and Development for Profit program, conducted in collaboration with AgriFutures Australia, Meat & Livestock Australia, the Grains Research and Development Corporation and Primary Industries and Regions South Australia.