Complex Diseases - Terms, Problems and Examples : Disease/Environment Interactions in Forest Decline. Proceedings of a Workshop of the Working Party Disease/Environment Interactions in Forest Decline IUFRO 7.02.06, Vienna, Austria, March 16-21, 1998

1999

S. 43-48

15 Lit.

Unselbständiges Werk

200085320

Terms are used in our discussions and publications to characterize e.g. certain symptoms, cause(s) - disease-relationships etc. etc. The use of terms facilitates the mutual understanding, - as long as everybody knows and recognizes the same definition. This is the primary crux of the problem, because the definition and understanding may change (from time to time ynd from author to author); further, some - not well defined - "terms" as "Waldsterben" become "ear-worms". The discussion on complexity of diseases reaches back to the early years of scientific forest pathology (HARTIG), but still we are eager to search for monocausal relationships. The expression "complex diseases" stimulates to remember and to consider multiple causes leading to forest decline phenomena of stands or/and species in certain regions. Discussing declines there has to be considered that three subcomplexes are involved: The constitution and condition of the host(s), the same for the biotic factors and the variation of abiotic influences. In connection with these invluences the question of time-lag (between initial influences and the development of symptoms) has to be included into considerations and conclusions. During the recent past some terms were confused very often, e.g. vitality and vigour - esp. in German publications. The difference is discussed. To illustrate some aspects of complexity the host-site-pathogen relationship will be discussed with the examples Melampsora allii-populina, Cenangium ferruginosum and Gremmeniella abietina.