BIOLOGICAL-CONTROL IN THE PHYLLOSPHERE - REALISTIC GOAL OR FALSE HOPE

There have been few successes to date for biological control of foliar pathogens in nature. Progress has been slow, possibly because biocontrol in this habitat is more difficult to attain than that elsewhere. More likely it is because research has been inadequately supported and endeavors have generally been conventional, fragmented, insular, and inconclusive. Significant advances will not be made until the leaf environment and epiphytic microbial communities are much better understood. Four general principles that may help to consolidate research efforts are: i) Success hinges on knowledge of species interactions and of the forces shaping the phyllosphere community (i.e. studies in synecology are needed); ii) colonization of a biocontrol agent is analogous to successful invasion of an introduced species; iii) fitness in the laboratory does not equal fitness in nature; and iv) improvements hinge on knowing the mechanism for biocontrol.