Predicting the establishment of pest reservoirs, and therefore pest infestation in sugarcane agroecosystems, is a challenge for the implementation of integrated pest management (IPM) programs. The objective of this work was to develop a Decision Support System that suggests plant species, located in a production area, that host a pest. A Knowledge Based system on Biological Interaction (KBBI) was then developed and coupled to DECIPESTS, a DECIsion support system for PEST management in sugarcane. KBBI compiles biological interrelations listed in the scientific literature, at three trophic levels (plant, pest, and natural enemy). DECIPESTS is based on IPM expertise and field observations and identifies the potential causes of insect pest infestations. KBBI and DECIPESTS both use Cogui software to handle and combine pieces of knowledge. According to observed damage, DECIPESTS informs on the potential pest. In return, KBBI suggests the wild and cultivated plants that are able to host the pest. The comparison with a local floristic inventory enables the determination of pest reservoirs. Applied to a case study in Senegal, KBBI and DECIPESTS showed for instance that Eldana saccharina can be hosted by nine wild plant species located in the irrigation canals: Typha domingensis, Sorghum verticilliflorum, Phragmites australis, Paspalum scrobiculatum, Echinochloa pyramidalis, and four species of the Cyperus genus. KBBI also showed that this species can be hosted by Zea mays and Oryza sativa, two neighbouring cultivated crops of socio-economic importance in the area. This latter result indicates that the management of Eldana saccharina has to be tackled jointly by local farmers to be successful. While DECIPESTS uses a tactical approach to identify possible causes of pest infestation, its combination with KBBI makes it a strategic tool to enhance IPM strategy at a local scale.