Euonymus scale, Unaspis euonymi (Comstock): host preference, and distribution of native and imported natural enemies in Virginia

Abstract

Studies were conducted in 1992 and 1993 to determine which of six Euonymus species and cultivars would sustain the highest populations of Unaspis euonymi (Comstock), as a food source for Chilocorus kuwanae (Silvestri). Analysis of data collected from field-grown plants and container-grown plants indicates that Euonymus japonicus (Thunb.) 'Albo-marginatus' would sustain the highest populations of U. euonymi.

In 1992 and 1993, surveys were conducted to determine the presence of existing natural enemies in Virginia as well as to determine the establishment of the imported predator, Chilocarus kuwanae. In 1992, C. kuwanae and parasites from the genera Aspidiatiphagus and Encarsia was found at several locations in Virginia Beach. In 1993, C. kuvanae was recovered in seven of the twelve Virginia counties surveyed. Either Aspidiotiphagus or Encarsia were found in nine of the twelve counties. A single specimen of Cybocephalus sp. was recovered from a sample taken in Fredericksburg.