 Banksia verticillata has been declared vulnerable under the federal Environment Protection and Biodiversity Conservation Act 1999 , and Rare under Western Australia 's Wildlife Conservation Act 1950 . A 1995 census yielded an estimated total population size of 4500 plants . Apart from dieback and aerial canker , frequency of bushfires and illegal picking have been cited as threats . Ongoing management includes monitoring of current populations , gathering more data on best response to fire , and restricting access to populations . Seed has been collected from many populations , but germination rates after ten years of storage are much lower than in Banksia brownii . <unk> is considered an option in the future , as is spraying with phosphite , particularly in the vicinity of Walpole . Used successfully on B. brownii but as yet <unk> with B. verticillata , phosphite boosts the resistance of both infected and uninfected plants , and also acts as a direct fungicide . Aerial spraying of phosphite boosts plant survival and slows the spread of infection , but must be carefully managed as studies have shown that foliar spraying of phosphite adversely affects root and shoot growth . 
