A dissertation relating to the nature of potato diseases and their control in the world agriculture : with an appendix covering a laboratory study of cultural and physiological characters of a potato dry rot fungus, Fusarium coeruleum (Lib.) Sacc. : dissertation presented for M. Agr. Sc. [Master of Agricultural Science] with Honours, University of New Zealand [Lincoln College]

The importance of the potato crop in World Agriculture cannot be gainsaid. Unfortunately this major crop of ours in heir to a large number of diseases, both parasitic and non-parasitic, and consequently potato culture in most parts of the world involves a constant struggle against these forces of destruction. Although there has been an immense amount of work performed on Potato Diseases, resulting in the accumulation of a large and varied literature on the subject, little effort seems to have been made to bring this widely scattered material together so as to present a more or less complete picture of the pathological status of this vital food crop before those concerned with its culture, distribution and improvement. This has resulted in an under estimation of the actual alarming state of affairs as people are either apt to overlook the danger till it really assumes epidemic proportions or are likely to be under a false sense of security, thinking that if the danger is absent today, it will remain absent even tomorrow. In the present work an attempt has been made at the synthesis of our current knowledge about Potato Diseases and their control. The necessity of it was felt because of the fact that there is no comprehensive book dealing with this subject exclusively to cater for the needs of both the potato worker as the scientist and the farmer as the practitioner, with the result that if anyone wants have some definite information on any topic, he has frequently to perform the Herculean task of exploring a veritable ocean of literature on the subject. In the first place every one is not so favourably situated as to have an unrestricted access to all the relevant literature required, secondly, even assuming that he has such access, the time and energy involved in such a search is almost breath-taking; and lastly, very often than not he is confronted with a maze of conflicting views which make his task really stupendous. The object of this work is to obviate such difficulties as far as practicable. Throughout the preparation of these pages, the aim has been to condense the extensive literature available on the subject to the size of a handy volume for the benefit of both the research worker and the farmer. The magnitude of the task before the writer can be guessed from the fact that if one attempted to compile all the published papers even on one potato disease like Late Blight or Leaf Roll, it would alone consume several volumes like the present one. It was but natural that the data produced should be cut down to the barest minimum, consistent only with the central idea presentation and all details should be culled out without ceremony. However, in attempting to do so no pains have been spared to present only the most accepted and current ideas regarding the diseases and their control measures. The writer would have liked to be a little more critical than he has generally been throughout the survey, but this could not be done only for the limitations of space and time. However, brief criticisms have been added wherever they were though absolutely necessary or where the issue at hand seemed too much controversial. This will be found chiefly regarding the names and identities of bacterial and virus diseases and their causative organisms. The breeding prospects for the chief potato diseases have received particular emphasis, since breeding is now unanimously acclaimed to hold the key for future disease control. Some apology for including the geographical distribution of the diseases into this description is necessary, since at first sight it may give the impression of superfluity to many. It will enable farmers, workers, seed importing agencies and controlling authorities to comprehend the actual infected areas of the world and take suitable precautionary measures when importing seed or table stock from such regions. The bibliography will be found to include a few more references than would be warranted by the contents. This has been done to provide readers more access to relevant literature if they like to have more information on any particular matter. Many of these references in turn will provide additional lists for the more enthusiastic. Attempt has been made to quote authorities for the information given but this has not been possible in each and every case for obvious reasons. Moreover, a particular statement made by one investigator might have been made by numerous preceding and succeeding workers and so to avoid repetition, reference has been made to one, or at any rate, to only a few. This has been made expedient through the limitations referred to above, and for no other reason. The Appendix contains an account of the small research project of a preliminary nature conducted by the writer himself. This work on the Fusarium Rot of potato was undertaken to gain insight into some standard laboratory techniques used in plant pathology, and through the field covered is extremely narrow, it has nevertheless served the objective admirably