Parasitism of the leaf-beetle Mesoplatys ochroptera Stal (Coleoptera: Chrysomelidae)

Abstract

Th e leaf beetle , Mesoplaty s ochropter a Sta Ê l has recentl y becom e a seriou s pest of Sesbania sesban (L.), a nitrogen - W xin g leguminou s tre e being eagerl y adopte d by farmer s in short - rotatio n plante d fallow s for soil fertilit y improvemen t in easter n Zambi a and elsewher e in Souther n Africa . Survey s were conducte d to identif y parasite s of M. ochropter a during the rain y seaso n in 1998 , 1999 an d 200 0 at severa l site s in the Easter n Provinc e of Zambia . Durin g the thre e years of rearing , no egg or pupa l parasitoid s wer e recovere d from M. ochropter a . In contrast , two natura l enemies , the braconi d parasitoi d Perilitu s larvicid a van Achterber g and the entomoparasiti c nematod e Hexamermis sp. wer e recorde d fo r the W rst tim e fro m bot h larva l an d adul t stage s of the beetle . P. larvicid a is one of the onl y parasitoid s recorde d as attackin g and emergin g fro m bot h the larva l and adul t stage s of the sam e holometabolou s insec t host . Parasitis m by the braconi d and the nematod e wa s low even durin g the pea k populatio n of the beetle in farmer ’s W elds . Apparen t parasitis m due to P. larvicid a was 4.5 and 5.5 % in larva e and adults , respectivel y. Hexamermis sp . infection s were recorde d in 7.3 % of the larva e and 0.3% of the adults . Both parasit e specie s wer e als o foun d in beetl e population s on wild Sesbania spp. Th e potentia l for biologica l contro l of th e beetl e is discussed