The red tomato spider mite Tetranychus evansi is likely to have originated from South America. It has spread recently as a new invasive pest of solanaceous crops in many parts of the world. In Benin, the first outbreaks were reported in 2008 with significant damage on tomato and African eggplant. Thereafter frequent outbreaks have been regularly observed in all vegetable production areas where yield losses of up to 100% are reported. This is a real challenge for desperate farmers who rely on chemical pesticides such as pyrethroids alone or in combination with organophosphates.
A first survey carried out in 2013 by IITA researchers in key agroecologies in Benin revealed T. evansi as the only mite found without any associated predatory mites. With the establishment of the Biorisk Management Facility (BIMAF), a specialized research and training platform on the premises of the IITA-Benin Station, IITA and its partners (National University of Agriculture in Benin UNA, icipe) advocated the classical biological control approach using the predatory mite Phytoseiulus longipes to control T. evansi. Thus, P. longipes was introduced to Benin from icipe, Kenya, in July 2016 and tested under quarantine conditions in the acarology laboratory at IITA.
A second field survey was undertaken in 2016 in vegetable production sites including abandoned tomato fields and revealed local predatory mites in association with T. evansi. Interspecific competition tests between the local predatory mites and P. longipes will be done with the active participation of farmers before the exotic natural enemy is released.
Ginette Azandeme-Houmalon: Acarologist (Université Nationale d’Agriculture, Benin)
Ghislain Tepa-Yotto: Entomologist, BIMAF coordinator, G.Tepa-Yotto@cgiar.org