Dysmicoccus wistariae (Previously Pseudococcus cuspidatae)

The taxus mealybug is thought to occur throughout the Northeastern US, including Massachusetts, New York, Connecticut, New Jersey, Pennsylvania, and Ohio. Its distribution also reaches into the central United States (Johnson and Lyon, 1991). Weiss (1915) first reported this species from Rutherford, New Jersey on Taxus cuspidata brevifolia and Rau (1937) described it as a new species, and a likely introduction from Japan in 1915 on T. cuspidata. Adult females are 0.16 inches long covered with a white powdery wax. Females may appear like they have 4 longitudinal lines in this wax, beneath which the body appears red in color. 15 filaments (waxy protrusions) are found along each side of the body with a longest pair at the rear end which is approximately 1/3 length of the body (Hamilton, 1942). First instar nymphs are reported as the overwintering life stage in New Jersey. They may be found in bark crevices on the host plant. In April and May few live mealybugs are found. However, by mid-June the population may increase considerably (Hamilton, 1942). Adult female taxus mealybugs are present from June to August and give birth to live young in the early summer. Nymphs and adults have been reported in Massachusetts in June but no eggs or young nymphs were seen (Weidhaas and Shaw, 1956). The exact life cycle and timing for this species is not fully understood. Weidhaas and Shaw (1956) call for further study of the life cycle of this insect, but Hamilton (1942) reports that live young are produced by this species (no eggs are laid). A single generation may occur per year in Connecticut and points northward; however, in New Jersey and points south, two or three generations per year may occur (Johnson and Lyon, 1991). There is discrepancy on this, however, as Weidhaas and Shaw (1956) report two generations per year possible in Massachusetts. Adults are reported to disappear on plants by September (Hamilton, 1942). Yew (Taxus spp.) are the primary host plants. Others in the above list are rarely impacted by this insect with the exception of possibly dogwood (Cornus spp.) where large populations have sometimes been reported (Johnson and Lyon, 1991). The taxus mealybug may be confused with the Comstock mealybug (Pseudococcus comstocki; also introduced into eastern North America from Asia) which may sometimes be found on Taxus spp. The two may be differentiated by the following: the taxus mealybug has a red body and red fluid when the body is squished; the Comstock mealybug has a brown body and brown fluid when squished. The Comstock mealybug also produces an ovisac, and the taxus mealybug does not (Hamilton, 1942).