Establishment, Spread and Impact of Pareuchaetes pseudoinsulata (Lepidoptera: Arctiidae) an Exotic Predator

Following the failure of an earlier attempt in the 1970s, a renewed effort towards the biological control of the Siam weed, Chromolaena odorata using the arctiid moth Pareuchaetes pseudoinsulata began in 1989 at the Crops Research Institute (CRI), Ghana. The objective was to reduce populations of C. odorata to non-economically damaging levels in a sustainable and environmentally friendly manner to enhance biodiversity. The natural enemy, P. pseudoinsulata was imported, mass reared and released on C. odorata fields after two years of studies on its biology and host specificity. Post release studies indicate that P. pseudoinsulata established in Ghana in 1994 and has reduced the popula-tions of C. odorata/unit area from a mean of 85.0 % in infested fields to 37.0 % in areas under control. The Populations of other herb species have increased from 13.0 to 36.4% and grasses from 2.0 to 26.6%. Plant species diversity per unit area has also increased from an average of 3 in previously infested C. odorata fields to 6 in controlled fields. About 37.9 % of the total land area infested with C. odorata in Ghana is under varying degrees of control. The reduction of the competitiveness of C. odorata by P. pseudoinsu-lata has positively enhanced forest regeneration and biodiversity in Ghana. All correspondences should be addressed to J. A. Timbilla, Biocontrol Unit, Crop