Silverleaf nightshade Strategic Plan - Weeds Australia

Vision /Aspirational GoalThe vision of this strategy is that new infestations of silverleaf nightshade in Australia will beminimised through increased surveillance and eradication, and that the impacts of existing coreestablished infestations will be reduced through improved management, capacity, motivation andcoordination.1 THE CHALLENGEFigure 1. Established core infestation of silverleaf nightshade – there are currently no economicoptions available to reduce infestations like this.Silverleaf nightshade is a summer-growing perennial weed from the Americas that grows to 60cmhigh and invades disturbed habitats. It was introduced to Australia accidentally and now severelyreduces crop and pasture productivity over a wide area. It is one of the world’s worst weeds ofarable land and occurs in many countries. The major asset at risk is the productivity of the entiremainland cereal cropping belt of southern Australia from southern Qld, through NSW, Vic and SA,to WA. This area underpins our agricultural export base and domestic food security. Onceestablished it is extremely difficult to kill, due to a perennial root system that can extend to a depthof 4m. It has been in Australia since at least 1901 and extensive established infestations now coverover 350,000 ha in SA, NSW and Vic across a wide range of soil-types and annual rainfall. Thereare also less extensive infestations in WA and Qld. It continues to spread within the importantAustralian cereal cropping production zone, primarily by seed transported by livestock and farmproduce, and also by root and stem fragments. Examination of a map of potential distribution ofsilverleaf nightshade in Australia (Fig. 3) shows that some areas of southern Qld and large parts ofarable WA are at risk. Large-scale distribution maps do not, however, show the potential for clean,highly productive paddocks on the same farm as a recorded infestation, or on nearby farms, to becolonised. There is still a serious risk for very large areas of clean, productive, arable agriculturalland to be infested in SA, NSW, Vic and WA.New infestations can be locally eradicated, if discovered and treated quickly. Once infestationsbecome established (Fig. 1) and spread to cover larger areas (c. >10ha) eradication is verydifficult. These infestations continue to spread by clonal root growth (c. 2m per year), and by5