THE EFFECT OF HERBIVORY ON THE INTERACTION BETWEEN THE CLONAL PLANT TRIENTALIS-EUROPAEA AND ITS SMUT FUNGUS UROCYSTIS-TRIENTALIS

The interaction between the smut fungus Urocystis trientalis, the plan t Trientalis europaea, and two herbivores (scale insects and voles) wa s studied in a two-year experiment. The results show that both the sca le insects and the voles preferred smut infected shoots to healthy sho ots. Fencing out the voles resulted in a significant increase in host density and a significantly higher disease level than were found in co ntrol plots. Thus, the data suggest that the voles may not only reduce host densities, but may also have a cleansing effect by the consumpti on of diseased shoots. The importance of including herbivores in studi es of interactions between parasitic fungi and their host plants is di scussed.