The cottonycushion scale, lcerya purchasi, in Florida

The cottonycushion scale was described by Maskell (1878) from specimens sent to him by Dr. Purchas from Auckland, New Zealand. The host was kangaroo acacia and the insect was named for Dr. Purchas. At that time only one other species was known in the genus Icerya (Maskell 1878). This scale is apparently native to Australia and made its way to California on acacia plants around 1868 or 1869, and in about ten years was causing damage to citrus groves in southern California (Ebeling 1959). The measures taken to control the cottonycushion scale in California were to change the methods of insect control and research; first in California and later in the whole United States. These new control methods led to the use of biological control and legislative quarantine (Ebeling 1959).

The following account of the introduction of this scale insect into Florida is largely taken from Gossard (1901). The ladybug, Rodolia cardinalis (Mulsant), was introduced into California in 1888 for the biological control of this scale (DeBach 1973). In 1893 the owners of a nursery in Keene, Florida (Pinellas County) sent an inquiry to someone in California about the possibility of the ladybug being used to control other scale insects in Florida. Apparently interpreting this as a request for the ladybug the party sent a shipment of ladybugs and included some cottonycushion scales as food for the ladybugs. The nursery owners who either didn’t see the scales or assumed they would be of no consequence, left the packing container near a citrus tree which eventually became infested. Florida now had the dreaded cottonycushion scale to contend with. The originally infested Florida trees were destroyed, but infested trees again appeared in late 1898. However, this was presumably from a new introduction from a tramp peddler of nursery stock in about 1895 (Gossard 1901).