A fuzzy-based index to identify suitable areas for host-parasitoid interactions: Case study of the Asian citrus psyllid Diaphorina citri and its natural enemy Tamarixia radiata

We developed a computational index to identify suitable areas for biological control using the interaction between an insect pest and its natural enemy. The index considers that environmental conditions should be suitable for the development of both insects and that the plants participating in the tritrophic system should be in the appropriate stage of development. In order to represent the uncertainty associated with empirical information and lack of data, we decided to use fuzzy sets theory to develop the index. We ran simulations for a specific case study and then validated them, classifying 54 locations in the state of Sao Paulo, Brazil, as areas of high suitabillity and low suitability for biological control of the Asian citrus psyllid, Diaphorina citri, using the wasp Tamarixia radiata. We constructed maps to provide a visual description of the interpolated data, using GIS (Geographic Information System). The index satisfactorily classified the areas, as confirmed by field data. The results suggest that in this state, the most effective period to use the parasitoid is September to March. The index can be easily used for different locations and species and has the potential to support biological control programs, helping entomologists and farmers to define the best period to use biological control.