Chionaspis pinifoliae (Fitch)

Chionaspis pinifoliae (Fitch), pine needle scale, is a common pest of conifers, especially in urban environments and Christmas tree farms. This insect is considered one of the most serious pests of ornamental pines in the U.S., especially mugo pine and Scotch pine (Johnson and Lyon, 1991; Miller and Davidson, 2005). In Québec, C. pinifoliae is an emerging pest of Christmas trees, but is not known to cause significant damage. Although not generally monitored by growers, C. pinifoliae can be an obstacle for export (Doherty et al., 2018). Morphological and biological similarities between C. pinifoliae and a closely related species, pine scale, C. heterophyllae Cooley, have led to taxonomic confusion. For example, there is a historical case of misidentification where a research program focusing on C. pinifoliae was found to have actually worked with C. heterophyllae when voucher specimens were reexamined (Nielsen and Johnson, 1973).

For the past two years, many Abies fraseri (Pursh) Poiret (Pinaceae) and Pinus strobus L. (Pinaceae) Christmas trees were rejected for sale in Florida because of contamination with C. pinifoliae. Rejected plant shipments were from North Carolina (FDACS-DPI sample numbers E2017-4458, E2017-4501, E2017-4688, E2018-6007, E2018-6128) and Canada (E2017-4743). These regulatory actions raised questions from Christmas tree producers and state Extension faculty at North Carolina State University (NC State) and the University of Florida. Shipments were rejected because of contamination with C. pinifoliae but literature indicated the species had been recorded in Florida since 1899 (Cooley, 1899; Merrill and Chaffin, 1923; Wilson, 1917; Dekle, 1976; Liu et al., 1989; Miller and Davidson, 2005). Each of these publications were based on records from the Florida Department of Agriculture and Consumer Services (FDACS) Division of Plant Industry (DPI) or the Florida State Collection of Arthropods (FSCA). Recently all of the DPI records and FSCA specimen slides reported as C. heterophyllae and C. pinifoliae were reexamined. All previous records of C. pinifoliae from Florida are either interceptions from other states or countries, or misidentifications of C. heterophyllae. In addition, only C. heterophyllae was found in a recent collection survey performed by Jerrold Moody (NC State) from Pinus sp. in the field in Lake County (E2018-278). Our findings provide strong evidence that C. pinifoliae does not occur in Florida.

Chionaspis heterophyllae is apparently native to North America including Florida (Miller and Davidson, 2005). Chionaspis pinifoliae has a relatively broad host range (reported on three host plant families: Cupressaceae, Pinaceae, Taxaceae) compared to C. heterophyllae, which is reported on only one host plant family (Pinaceae). Gwiazdowski et al. (2011) studied specimens from 320 North American localities including seven from Florida and 51 host species within the Pinaceae and found 10 cryptic species similar to C. heterophyllae and C. pinifoliae using morphological and molecular tools. In support of our conclusion, they also found only C. heterophyllae in Florida. Therefore, it is likely that quarantine activities carried out by DPI over recent years have helped prevent the establishment of C. pinifoliae in Florida.