A threat to the continued existence of Bermuda's cedars arose in the mid-1940s when the species was attacked by two species of scale insects, "Lepidosaphes newsteadi" and "Carulaspis minima", which were unintentionally introduced from the United States' mainland during the wartime construction of US airbases in Bermuda. By 1978, these parasites had killed 99% of Bermuda's cedars, some 8 million trees. However, the remaining 1% of the trees proved somewhat resistant to the scale insects, and efforts by Bermuda's Department of Agriculture, Fisheries and Parks to propagate scale-resistant plants throughout Bermuda have helped in protecting the trees from extinction.