mirids in Amazonian Ecuador
The most important
insect pests are of cocoa are mirids (Heteroptera: Miridae), also known
in Ghana as Sankonuabe. Current surveys indicate 25-30% of the national
acreage in Ghana has significant mirid damage, giving annual losses estimated
at 100,000 tonnes. Four species are present in Ghana with Distantiella
theobroma and Sahlbergella singularis being the major species.
They occur at low overall densities but often aggregate in "pockets"
where conditions are particularly favourable, e.g. a break in the shade
of mirids can be achieved with four sprays of insecticide during the main
mirid season but insecticide spraying for control also kills natural enemies
of mirids and other pests. This can lead to secondary pest outbreaks and
the use of cocoa insecticides on non-cocoa crops poses problems risks
to health. Thus, CABI scientists (Drs
Oduor and Moore) and their
collaborators in Ghana are searching for a safe, effective biopesticide
alternative using fungi pathogenic to mirids. Extensions of this work
into Cameroun that involves training of Camerounian scientists.