The main threat to "B. brownii" is dieback caused by the introduced plant pathogen "P. cinnamomi", a soil-borne water mould that causes root rot. Studies of the effect of "P. cinnamomi" on "B. brownii" have found it to be "highly susceptible" to dieback, with specimens "frequently and consistently killed in the wild". As of 2007, all major populations of "B. brownii", and all but one minor population, are suffering from dieback. Moreover, all populations are in an area vulnerable to dieback, so even the uninfected population is considered under threat. According to Byron Lamont, "the demise of this species in the wild appears imminent."