The majority of modern insect extinctions are likely unrecorded, despite increasing concern for this hyperdiverse group. This is because they are either yet to be discovered and described, their distributions and host associations are poorly known, or data are too sparse to detect declines in populations. Here, I outline the likely extinction of an Australian mealybug, Pseudococcus markharveyi Gullan 2013, which was discovered and described less than 15 years ago but was highlighted recently as one of five most threatened invertebrates in Australia from recent bushfires. The synergistic threats of dieback disease (Phytophthora cinnamomi Rands 1922) and inappropriate fire regime as a consequence of climate change have decimated host plant populations of the critically endangered Banksia montana (George 1996) Mast & Thiele 2007 and the montane habitat of both organisms, thereby leading to the coextinction of the mealybug. Its loss occurred despite attempts at conservation management and illustrates the general insect extinction crisis that Australia, and the world, is facing. The majority of Australian mealybugs are not receiving the same attention as P. markharveyi. Many poorly known species either remain undetected, without formal names, or data on their distribution, abundance and critical habitat are too scant to assess their conservation status. I also discuss the diversity of Australian mealybugs more generally and their need for conservation.