In spite of the importance of microorganisms in the success of tri-trophic interactions, their role has been overlooked in the past. Microorganisms might be pathogens, mutualists or symbionts of at least one of the partners of the interaction. Today, understanding what are the costs and the benefits of microorganisms is a central part of the study of tri-trophic interactions. This knowledge might pave the way to the development of new and sustainable control strategies. The development of Zebra Chip represents a good example: this disease affecting Solanaceous was described for the first time in 1994. It is today one of the worst emergent diseases in the US and its control might necessitate the understanding of the relationship between the vector and the pathogen or between different microorganisms in the vector or the plant.  

Results/Conclusions

Microorganisms are often let out of the equation when studying tri-trophic interactions in spite of their effects on every partner. The understanding of their importance in the outcome of the interaction might open the way to new management strategies.