Timing to control nightshade

On their mixed-farming aggregation of 3200ha they have developed a rotation of three years of cropping followed by three years of pastures to reduce weed, crop and livestock impacts. 

Although stock losses are rare, they have recently lost some valuable rams that were feeding in an infested paddock with the problem weed also causing ill-thrift. 

The Rowling family are one of the producer case studies highlighted in the first national guide for silverleaf nightshade with input from scientists, farmers, industry and community groups. 

Silverleaf nightshade is the hardest weed the Rowling partnership have to deal with, particularly due to its long flowering period and persistence.

They have been using the best management guidelines for 10 years by controlling seeding and running down the root reserves with the aim to reduce the numbers of scattered populations that can be spot-sprayed.

Surveillance searches for new patches have become part of the Rowlings normal farming operations and they have observed disease-affected plants, and some damage from grubs that eat berries. 

The Rowlings think that silverleaf nightshade has affected property values in the range of $125-250 per ha and if buyers are aware of the weed it can take a long time to sell the land.

Silverleaf nightshade is a Weed of National Significance (WoNS), with widespread infestations in New South Wales, Victoria and South Australia, and localised infestations in Western Australia and Queensland.

NSW Department of Primary Industries (DPI) principal research scientist, Hanwen Wu, said the highly persistent summer-active perennial invades crops and pastures and has caused yield losses of up to 75 per cent in the eastern states.

“The good news is silverleaf nightshade can be managed through timing and persistence in applying the controls,” Dr Wu said.

“We have developed a dual action approach to weed management, which offers improved long-term control options to deliver economic benefits for farmers and environmental outcomes for the community.

“The key element in managing silverleaf nightshade is to target both seeds and roots.”

As part of the national project, Dr Wu and his team established more than 350 on-farm trials across Australia, covering 95,000ha with 150 trials in NSW, from Nullamanna to Culcairn.