Beetles eat blue heliotrope
From the February 2009 edition of Agriculture Today.
A small black beetle with red stripes is demolishing blue heliotrope in the Capertee Valley.
The blue heliotrope leaf beetle won’t eradicate the weed, according to district agronomist, Jenene Kidston, but can be expected to help reduce plant populations, and reduce its impact on farms and the environment.
In 2003 NSW Department of Primary Industries (DPI) began a biocontrol program by releasing the blue heliotrope leaf beetle (Deuterocampta quadrijuga) on George and Bruce Richardson’s property, "Euralla" on the Nile River at Glen Alice.
"In the first few years I was pretty disappointed. We released the beetles and didn’t ever see them again," Mr Richardson said.
NSW DPI biocontrol officer, Peter Proctor, continued to breed the beetle in shade houses in Mudgee.
In 2005 and 2006 more beetles were released in the valley.
"In the summer of 2007 farmers started to notice beetles on blue heliotrope plants," Jenene Kidston said.
"In 2008 beetle numbers had increased to the point where they are having a serious impact on the plants on the Richardson’s property.
"Plants are still there but the beetles have stripped all their leaves, weakening the plants and reducing their ability to flower and produce seed."
Ms Kidston says the Richardsons are now taking an integrated approach to managing blue heliotrope.
Their plan includes healthy competitive summer growing pastures, herbicides where necessary, careful grazing management and blue heliotrope leaf beetles to weaken the plants and reduce flowering.
The beetles are now spreading throughout the valley.
Wendy Williams of Wiraki Alpacas has identified the eggs, larvae and adults on plants on her property, 18 kilometres from the Richardsons’ release site.
Beetles have also been identified on properties in the valley where they have not been released.
"It’s great to see the beetles spreading like this," Ms Kidston said.
"They only eat blue heliotrope, so they have to seek out blue heliotrope plants for food."
Contact Jenene Kidston, Mudgee, (02) 6372 4700, jenene.kidston@dpi.nsw.gov.au
