Introduction, propagation, and liberation of two parasitoids for the control of spiraling whitefly (Homoptera: Aleyrodidae) in Taiwan.
The spiralling whitefly (SWF) (Aleurodicus dispersus Russell), a polyphagous insect pest, was first discovered in southern Taiwan in 1988. A total of 539 adults of Encarsia ?haitiensis Dozier and 40 adults of E. guadeloupae Viggiani was introduced from Hawaii to Taiwan on 10 December 1995. After being screened for three generations in a quarantine room at TARI, these parasitoids were field released in central, southern, and eastern Taiwan. Overall, a total of 57 032 adults of E. ?haitiensis and 66 929 adults of E. guadeloupae, respectively, were released from April to December 1996 and again from March 1997 to February 1998. These parasitoids were recovered after about 12-24 days (after 3 months at Wufeng) following the first release in 1996. However, field surveys conducted in 1998 and 1999 revealed that only E. guadeloupae had become established. Although the population density of E. guadeloupae reached 0.21 to 0.77 pupae per leaf on Psidium guajava L., the 4th instar nymphs and adults of SWF still increased from 0.48 to 3.19 per leaf from September to December 1997. The population density of E. guadeloupae ranged from 0-68% of that of SWF on Euphorbia pulcherrima Willd., Terminalia catappa Linn., Acalypha wilkesiana Muell.-Arg., and Bauhinia racemosa Lam. from September 1998 to June 1999. The parasitoids were found to be ineffective at controlling SWF on E. pulcherrima along roadsides in Chutien, Pingtung Hsien. The methods and procedures for the mass rearing of SWF and its parasitoids are also presented in this paper.