Abstract:
Studies were conducted in two districts of eastern
Uganda from 1997 to 1999 to introduce and monitor the establishment of an
exotic parasitoid, Cotesia flavipes Cameron (Hymenoptera: Braconidae),
for the control of the stemborer Chilo partellus (Swinhoe) (Lepidoptera:
Pyralidae), and also to determine the stemborer species complex in maize and
sorghum. The study confirmed the presence of four important stemborers, two
pyralids Ch. partellus and Eldana saccharina Walker and two
noctuids, Busseola fusca Fuller and Sesamia calamistis Hampson.
Chilo partellus was dominant, constituting 53-88% of stemborers found
followed by B. fusca at 8-37 %. The most abundant local parasitoid
was the larval parasitoid Cotesia sesamiae (Cameron) (Hymenoptera:
Braconidae). The pupal parasitoids Pediobius furvus Gahan (Hymenoptera:
Eulophidae) and Dentichasmias busseolae Heinrich (Hymenoptera:
Ichneumonidae) were also recorded. Parasitism of Co. sesamiae on Ch.
partellus ranged between 0 and 13.1 %. The introduced Co. flavipes
was recovered from all sites in four consecutive seasons (between 1998 and
1999) causing parasitism of between 4 and 32.9 % on Ch. partellus.
Cotesia flavipes was also recovered from the indigenous stemborers
B. fusca and S. calamistis. This study indicates that Co.
flavipes has established in eastern Uganda.