Blackberry infestations explode in Victoria

Repeated bushfires, followed by three wet seasons has led to an explosion in blackberry infestations that are blocking bush access.

Sue Donnelly tries to get her horse through a tangle of blackberries at Sheepyard Flat, in the Upper Howqua Valley.

Victoria’s blackberry infestations have spread across more than a million hectares, on the back of repeated bushfires, blocking forest tracks and access to rivers for anglers, horse riders and bushwalkers.

Victorian Blackberry Taskforce chair Lyn Coulston said spraying out such a vast and dispersed area was impossible, with biocontrol the only option.

But while eight strains of blackberry leaf rust fungi were released in 2008, Ms Coulston said no other potential pathogens or pests had been released since then.

While the leaf rust fungi have been successful in reducing blackberry biomass in open areas, they have had little impact under forest canopies, such as in forests and along creek lines.

The taskforce has previously reported that work on purple blotch disease, a promising biocontrol agent that is active in shady areas and kills blackberries, would be effective.

But research into the pathogen, which was funded by the federal and Victorian governments, ceased in 2012.

Ms Coulston said the taskforce needed community support in lobbying governments to revisit biocontrol, given the impact of blackberry infestations on native species and access to the state’s waterways and forests.

But a Victotian Department of Energy, Environment and Climate Action spokesman reported Agriculture Victoria and Meat and Livestock Australia jointly funded a $1.245 million research project that explores a cane-boring sawfly (Phylloecus faunus) as a potential new biological control agent.

But the last summarty report on the cane-broing beetle satted more funding was needed for host-specificity testing.

In the meantime VRFish chief executive Ben Scullin said blackberries created an impenetrable wall on either side of streams, particularly in Victoria’s north east.

“Once you’re in the river, you can be walking up stream (fly fishing) for a kilometre or so and not be able to get out,” Mr Scullin said.

Buckle Up Bush Rides owners Shelly and Paul Skvor said blackberry infestations were getting worse, as they spent ever more time clearing tracks to get their horses and clients into the forests of the Howqua and Wonnangatta Valleys.

“We spend a lot of time with whipper snippers and even chainsaws clearing blackberries and we always ride with a hand saw and secateurs,” Shelley Skvor said.

Bellarine Peninsula farmer and keen tail rider Sue Donnelly has been mapping infestations across central and eastern Victoria, with the help of locals.

“This year’s spring growth that I just witnessed, has exploded beyond comprehension,” Ms Donnelly said. “What I have seen has left me distraught and devastated and to think that there is in excess of two million acres (1.4m hectares) of blackberry infestation coverage in similar conditions across the high country.”

“I can’t believe I have to sit by and watch this environmental disaster, which is far worse in areas hit by bushfires.”