Techniques of improved quarantines
Other forest products
Plant protection organizations
The need for effective plant quarantines between continents, regions and countries and even within countries is no longer considered to be a debatable subject. The disastrous results of having accidentally introduced exotic pest organisms into new environments throughout the world have been documented on many occasions. The natural control mechanisms made up of predators, parasites, and inherent host plant resistance seldom are found in new environments; thus, introduced species are often much more destructive in new habitats. Secondary invaders in one region may become primary pests in another, as Sirex noctilio F. has done in New Zealand. Closely related host species and varieties of crop plants may be more susceptible to attack, and may range over wide areas of the land mass and thus create a control problem of great magnitude. It is thus in the public interest that individual countries have legal authority, utilizing biological knowledge to prevent the entry and spread of exotic pests injurious to plants. Along with legal authority it is essential that resources in competent technical staff and laboratory facilities are available to translate the biologically significant discoveries into more effective programs.
McCubbin1 (1954) outlines four requirements for an effective plant quarantine:
1. The establishment of a national organization. Because of the complexity, immensity and the long-sustained nature of the effort, only a national organization can command the means for dealing with such a worldwide problem. The national organization must, of necessity, provide resources for studying foreign pests and compile accurate information on life histories, distribution, host plants, host range and possible means of introduction. Much information has already been compiled but, as McCubbin stated so appropriately, "it may be exasperatingly barren of details that the quarantine official would wish to know." It is, therefore, essential within the national organization that provision be made for research to clarify those problems that are specific to quarantine.2. A system of control over the importation of pest carrying materials.
3. Provision for a national pest survey.
4. Provision for internal plant pest control.
1 McCUBBIN, M. A. The plant quarantine problem. Copenhagen, Ejnar Munksgaard, 1954.
The Symposium brought into sharp focus the multitude of problems and the difficulties confronting those organizations charged with preventing the introduction of and limiting the spread of pests and diseases of forests and forest products moving in international trade channels. In his Paper, "The intercontinental spread of forest pathogens," V. J. Nordin, expressed an appropriate working philosophy for the entire Symposium: "Effective quarantines are the first line of defense against international spread of forest pathogens. Every year that introductions are delayed by quarantine barriers means that we shall have more time to perfect disease control through silvicultural, chemical, and genetic approaches; every year's delay permits the refinement of quarantine procedures based on research findings; every year's delay provides opportunities to establish and improve eradication machinery and methods, and every year's delay gains time to implement recommendations based on co-ordinated international co-operation."
The International Plant Protection Convention, Rome, 1951, recognized the need for international co-operation for controlling pests and diseases of plants and plant products and for preventing their spread across national borders. Member countries agreed to establish measures that would ensure closer co-ordination of those measures directed to these ends. The principles adopted in 1951 were directed primarily toward agricultural plants and commodities and have, therefore, not provided adequately for many commodities of interest to forests and forest products protection.
The dispersal internationally of destructive organisms of forests may be either natural or artificial. Generally speaking, natural dispersal by wind, water, birds, etc., is considered to be beyond the control or regulation of man; it is important, nevertheless, that the part played by these agencies should be known. The artificial dispersal agencies, on the other hand, have been responsible for most, if not all, of the instances where wide natural barriers, such as oceans, deserts, and mountain ranges, have been overcome. It is not possible to document precisely the exact time or vehicle of transfer of each and every exotic Pest introduced into various countries, but sufficient data have been compiled to specify the major risk areas and materials.
Along with the increase in volume, speed, and complexity of international trade and traffic, the problem of plant quarantine has become more difficult to administer as well as more essential. No parts of the world are more than a few hours separated by jet aircraft, and ships travel from continent to continent in a few days with improved facilities for the safe shipment of fresh commodities, all of which contribute to aiding the safe arrival of produce as well as organisms associated with them. It is only in the area of artificial dispersal of plant pests that the quarantines can take effective action. Because of the large volume of raw and manufactured forest products, capable of carrying pests and diseases, moving in international trade channels, it is considered virtually impossible to provide complete inspection and/or treatment. Nevertheless, each country should be prepared to provide as much protection for the country purchasing its products as it expects from the country from which purchases are made.
The plant quarantine requirements of each country will, of necessity, vary depending on climate, the type of forest and other ecological conditions peculiar to the country concerned. In general, however, the establishment and enforcement of plant quarantine restrictions should be based on the following principles, proposed by the Working Group on Forest Insects and Diseases, North American Forestry Commission, May, 1963, and endorsed by the Symposium:
1. The pest concerned should be of such a nature as to offer actual or expected threat to substantial interests.2. The quarantine should represent a measure for which no other substitute involving less interference with normal activities is available.
3. The objective of the quarantine, either for preventing an introduction or for limiting spread, must be reasonable of expectation.
4. The economic gains expected should outweigh the cost of administration and the interference with normal activities.
5. The quarantine should be based solely on biological grounds and should not be imposed as a means of limiting trade for economic reasons.
6. The quarantine should place no more restrictions on normal trade than is necessary to afford the needed protection.
7. Quarantine restriction should be kept under continuous review and should be modified promptly when conditions permit. For example, the eradication of a pest concerned or the development of new treatments or other safeguard techniques would permit the safe movement of material that it had been formerly necessary to exclude.
PROPAGATING STOCK
Recognizing that most plant protection organizations have not given as much attention in the past as is warranted to forest propagation stock, for example, seeds, plants, scions, cuttings, etc., the Symposium attempted to provide maximum safety guide-lines. Past experience has provided many instances of careless introductions of relatively mature plants, plants with soil and generally uncertified and uncertifiable materials that have had serious consequences. Studies made of the avenues of entry of pests in commerce by many plant protection organizations represented at the Symposium have shown rooted plants with soil balls, or adhering soil, constitute the greatest of all pest risks. Practically every stage of insects, plant diseases, and nematodes may be found associated with plants shipped in this manner.
The Symposium agreed that it is highly desirable that all countries, in the interest of protecting both exotic and indigenous forests, should adopt realistic policies to reduce to a minimum the risk of pest introduction.
It has long been recognized that seeds constitute the safest possible means of transferring propagation material. It was noted, however, that there is a lack of information on seedborne diseases in forests and, therefore, precaution should be taken to provide for, and require, that the seed be thoroughly cleaned so as to remove all possible infective debris and, if necessary, disinfection by fumigation and/or fungicidal dressings. Although there are few known forest diseases that have been shown to be transmitted by seed, this phase of forest research has not been given the amount of attention it perhaps warranted. Orton2 (1931) reported that agricultural workers have shown at least 477 pathogens (bacteria, fungi, viruses, and nematodes) to be seedborne. More research in this area should therefore be undertaken.
2 ORTON, C. R. Seed borne parasites: a bibliography. W. Virginia Agric. Exp. Sta. Bull. 245, 1931.
Other means of introduction should be used in limited quantities to permit post entry quarantine. Cuttings are the safest of many alternate means of plant introductions, but even these may carry stages of fungal, bacterial, and viral pests arid diseases that can only be detected by close examination during active growth.
Logs, poles, pulpwood, partially processed and completely finished wood products represent varying degrees of threat as vehicles of pest transmission. Any of the unprocessed items with bark attached are potential carriers of bark beetles and borers. In addition to the inherent potential risk, detection by ordinary inspection methods is virtually impossible. Crating material and dunnage on ships have traditionally been provided from low grade and cull lumber stocks. No other commodity was subjected to as much criticism by the Symposium. It was felt that two alternatives were available to remedy the situation: either treatment by fumigation, kiln drying, or upgrading the class of materials used. It was pointed out that it seemed worthless to demand special requirements for crating and packaging, if these might be reinfested from infested dunnage during the voyage.
Since the volume of raw or partially manufactured forest products is so great, the industry itself must be urged and encouraged to adopt an inspection procedure by selecting and grading its products for export, so that it can comply with the phytosanitary requirement of importers.
Since political boundaries seldom represent distinct ecological regions, pests introduced into one country may constitute a threat to many adjacent countries. Therefore, FAO was instrumental in suggesting and encouraging the establishment of regional plant protection organizations. The purpose of these was to standardize the safeguards against pest introductions and thus provide mutual assistance directed toward that end.
A number of regional organizations are now in existence, such as the European and Mediterranean Plant Protection Organization, the Inter-African Phytosanitary Organization, the North American Forestry Commission and the Plant Protection Commission for Southeast Asia and the Pacific Region. Good progress has been made in providing for more uniform safeguards for larger geographical and ecological areas.
As a result of the attention given to the establishment of plant protection organizations with the enactment of adequate legislation, both facilities and efficiency have been improved. However, there are many areas in which improvements and greater efforts are required. Quarantine enforcement is often handicapped by difficulties of detection and methods of treatment. This is particularly true with virus diseases and nematodes. The role of the latter is virtually unknown, yet their presence associated with rooted propagating material is well documented. Research directed toward quarantine improvements in all phases, including detection and treatment of suspect material, should constitute an integral part of all plant protection organizations.
The extent to which the forest resources of the world continue to be renewed to meet the ever increasing demands for wood products and fiber, depends upon the wisdom and efficiency provided for their protection. Intensive educational programs on an international scale are required if co-operation by the public in general is to be obtained. The World Health Organization has led the way in providing worldwide realization of the risks involved in the international transmission of infectious diseases. Perhaps plant protection organizations throughout the world might learn from, and adopt some of their techniques.
