The following documents are aimed at presenting features of host/parasite relationships in some fungal wilt diseases, many of those appearing to have no obvious counterpart in current literature. The present observations and interpretations will perhaps be considered by some as being counter current in an agitated ocean of thoughts when the necessity of conducting ultrastructural studies to solve pathological problems appears to hold second rank. Indeed, the fluttering pennant of molecular genetics on the flagpole of scientific research overcasts that of the more difficult to evaluate benefits of microscopic observations. It needs to be emphasized that without the foremost presence of the latter, the former may not have evolved and that, most importantly, without its in situ application, knowledge of molecular aspects would linger on as stereotypes and short of providing a better understanding of infection mechanisms, albeit valuable and technically interesting these aspects may be. The present documents may also be considered to represent a synthesis of our perceptions of the infection process in these diseases. The type and style of presentation adopted are personal (proposed by the senior author) and do not correspond to the usual format of most Journals. Hopefully, by grouping illustrations of proper size and magnification and with the juxtaposed corresponding text might permit the reader to more easily follow the presentation. Similarly, this type of presentation may help to obviate many of the criticisms that we have often been confronted with such as: “features difficult to see because of fragmentation and improper magnifications of photomicrographs; repetitions between text and legends to figures; over interpretations, seemingly due to deficiencies in the above mentioned” and so on, concerning some of our more challenging and most fundamental papers.

The varied illustrations now produced may help to show the value of “milking” the colloidal gold labelling techniques, in recollection of comments received by some reviewers in their evaluation of some of our data. We hope, furthermore, that people will better appreciate the value of illustrating in more than in one photograph and at sufficient magnification the features to be seen (judged to be necessary to hammer down essential details). A verse written by T.S. Eliot (In “Four Quarters”): “Only through time time is conquered” may be mimicked here saying: “Only through repetitions is new knowledge moulded”. The present documents may also partially satisfy persons requiring statistical analyses to become convinced of the importance of a problem showing that the features described were at least observed more than once (indeed, some of the features illustrated have been observed by examining hundreds of photographs, still in possession of the senior author). Moreover, by using a number of illustrations, the necessity of making cross references to them to show features will be minimized, and the reader will be left with the privilege of verifying how the points pinpointed in one illustration can be seen in the others

A few of the present illustrations are thus reproduced in larger sizes and greater magnification, and adding descriptions of new features, of a few previously published illustrations in the following Journals: Phytoprotection, New Phytologist, Canadian Journal of Botany, Microscopy and Microanalysis, Mycological Progress, in chapter 13, of “Defense Mechanisms of woody Plants against Fungi” (Springer-Verlag, 1992), and in some of the Proceedings of Scientific Meetings, as listed in the reference list.

Finally, confronted with some problems and questions that our observations might raise, some researchers may require to immediately having the answers to become convinced. Of course, the avenues of research often meet these cross roads of doubts and of the “I do not believe it”, which somehow are necessary for progress to occur, in as long as the lights of circulation do not tarry on red. One change to green might be to recognize that it is at least warranted to ask questions about existing incomplete or incorrect answers to previous problems, and as stated otherwise, according to Leon Daudet (translated from French by the author): “to reach doubt about doubt is the beginning of certitude”. However, the author does not necessarily adhere to Nietzche’s statements regarding doubt and certitude, except to say that too absolute a certainty should remain open to scrutiny.

P.S. Any person interested in pursuing research on some aspects of the present data is welcome to obtain any of the thousands of Epon-embedded samples (that will still be shelved for a while) of the diseases studied and of the various experiments made. The present documents, either in DVD or printed forms are available at a minimal price, to mainly cover costs of reproduction and mailing.

However, any surplus amount gratuitously received would apply to creating a Research Fund to promote and unify research on wilt diseases, particularly Dutch elm disease. A main objective of this Fund would be to grant scholarships to students interested to carry out work on concerted anatomical, histopathological and biochemical aspects of these diseases. Also, hopefully, by this means, closer ties of cooperation could be established between Institutes that are or were involved with projects on these aspects, in Europe (for example, the group of Prof. Gil and Dr A. Solla in Spain, Dr A. Santini in Italy, Dr E. Collin in France) as well as in America (USDA, Delaware Ohio, hopefully also as a continuation of Research undertaken by late Prof. Smalley at the University of Wisconsin, of that of Dr Wayne Sinclair at Cornell University, and so on). In Canada, Dr Louis Bernier, Laval University, is still conducting fundamental work on genetical aspects of the Dutch elm disease pathogen, and I believe that the work carried out by Dr M. Hubbes at the University of Toronto is worth being continued. Of course, any outbreak concerning this disease would favour progress in combating other wilt diseases and viceversa, valuable data concerning these other diseases would profit to the former.




Many people have diversely contributed towards fulfilling our investigations over the years. Their assistance has been acknowledged in the papers previously published and listing here their names and affiliation would be too lengthy. May it be mentioned that the work carried out by the senior author during his career as a research scientist and then as an Emeritus Researcher (until 2006) was with the support of the Laurentian Forestry Centre (LFC), Canadian Forest Service, Department of Natural Resources Canada, and as particular contributions in the present case. Grants from NSERC, Canada, to the senior author, and jointly with Dr Louis Bernier, « Université Laval », Quebec, from the Quebec FQRNT research grant agency (formerly FCAR), were also valuable contributions that allowed us to conduct certain aspects of the work concerning wilt diseases. The investigation regarding ultrastructural studies of initial bud proliferation on stems of Tillia cvs. was supported by the «Service de l’Environnement», Quebec City. Tests with a gold complex RNase were conducted with the participation of Dr N. Benhamou, « Université Laval », and that with gold complex antifimbriae also jointly with Dr Pierre Desrochers, Laurentian Forestry Centre. Special thanks are addressed to Ms Marie Simard (LFC) for the “colouring” of gold particles in the first pages of this work. A faithful assistance was provided by Ms Carole Devin (wife of the senior author) who has actively participated in the preparation of the articles. Her encouragement and support were greatly appreciated. Ms Sabrina Crevier kindly spent much of her leisure time carrying out the graphic work.

G. B. Ouellette
3413, de Sarnia Street
Quebec (QC) Canada
GIX 2K5

in cooperation with
H. Chamberland
519, Givot street
Québec (QC) Canada
G1B 3A1

P.M. Charest
Faculté des sciences de
l’agriculture et de l’alimentation
Université Laval,
G1V OA6

info@wilt-ism.net