W. V. BENEDICT
W. V. BENEDICT is Director of the Division of Forest Pest Control, Forest Service, U.S. Department of Agriculture, Washington, D.C.
This paper was presented at the Symposium on Internationally Dangerous Forest Diseases and Insects organized by FAO with the support of the International Union of Forestry Research Organizations (IUFRO) and held at Oxford, England, from 20 to 30 July 1964.
The background to the organization of the symposium may be stated as follows:
(a) The present-day trend in silviculture is toward increased emphasis on forest plantations, involving higher investment for an expected higher production.(b) This trend, dictated by industrialization and legitimate claims for an increased and more rational production, typically leads to the establishment of extensive, even-aged forest stands consisting of one or a few species over large areas.
(c) In contrast to natural forests, plantations create conditions under which the risk of serious disease and insect attacks is much increased.
(d) Much effort and money are being invested in plantation forestry through site preparation, fertilization, tree improvement, etc. These investments can be materially reduced or lost through disease and insect attacks. These negative production factors require as much attention as do the positive factors, particularly because of their unpredictability.
The report of the symposium will be published by FAO.
Principles, procedures, and problems in the United States
Guiding principles
There are several guiding principles and considerations governing the control of forest diseases and insects that we follow in the United States. These principles, together with a brief discussion of each, include:
1. The pest in question must pose a major threat to the forest resource affected. After that has been established, there must be an effective method available for direct or indirect control; a favorable cost-benefit relationship in the control practice; and, if there are hazards in connection with the use of pesticidal chemicals, there must be effective safeguards.
We make careful assessments of each forest pest problem before deciding for or against control. These assessments include a thorough evaluation of the current and potential significance of the insect or disease situation, and of the ecological and economic considerations that relate to it. Our purpose is to determine the results likely to accrue as a result of control, and the damage or loss to be expected if control is not undertaken.
In our judgment, thorough and penetrating evaluations of pest situations are essential if control programs are to rest on solid foundations. It has been our experience that skimpy or superficial evaluations lead to control actions of questionable worth. We therefore consider factual assessments of pest problems as key factors in deciding for or against control programs. We believe they should be as technically sound and as comprehensive as it is possible to make them.
2. Application of control measures must be thorough and complete. Thorough and complete application of methods available for checking pest damage is vitally important in controlling forest diseases and insects. Pest control must meet the technical standards worked out and prescribed by research; otherwise, results may be less than satisfactory and the work done can, and often does, end up largely as wasted effort. This is a fact that forest managers in the United States can sometimes fail to appreciate. Certain details in some forest management activities can be neglected and still produce passable results. It is difficult for them to understand that this is not so in pest control. For example, the removal of 90 percent of Ribes plants - the alternate hosts of white pine blister rust - from an area may be time-consuming and costly. In spite of this, the effort can be largely wasted if the residual Ribes are sufficient to carry enough blister rust to destroy a pine stand. Likewise, an insect control project, which can be very costly, may produce little or no benefits if the residual insect population is sufficient to regenerate promptly and kill the trees under attack.
The point we strive to keep in mind is that control of the pest is the objective - not the mere destruction of large numbers of insects, pathogens, or host plants. In other words, pest reduction must be sufficient to prevent economic damage to the forest. This demands rigid adherence to technical standards.
3. Research must be dynamic and continuing. It is largely through basic and applied research that pest control methods are derived. Thus, pest control can progress no farther and no faster than research can provide the necessary control tools. To be most helpful to pest control, research must not only include basic studies about diseases and insects, but also methods improvement and developmental work attuned to the day-by-day problems encountered in control operations.
In the United States the public is becoming increasingly aware of the damage and loss caused by forest pests, and pressures are mounting for the prevention or reduction of this damage and loss. As awareness and pressures increase, they bring in their wake additional problems. For example, there is often a demand for control even though it may not be possible to satisfy completely that demand. Despite all the research that has been and is being done, there is much that we still do not know about the control of forest diseases and insects. For those of us responsible for control programs, this can and often does lead to difficult situations. While we always do all we constructively can to provide a control service, we are often forced to withhold approval for control work, even though it is badly needed, because we lack an adequate or safe method.
The increasing awareness of the importance of forest diseases and insects, and mounting pressures to cheek their depredations, are bringing a sense of urgency to forest disease and insect research in the United States, such as did not exist as little as ten years ago. The need to provide solutions promptly to the many technical and other problems confronting control organizations is being increasingly impressed on research staffs.
4. Resource management and the public must be well informed. Adequate forest pest action requires that the forest resource manager and the public alike have a clear and realistic understanding of what can and what cannot be done to prevent or suppress damage and loss caused by forest diseases and insects. Much good in the overall field of prevention and suppression of pests can be accomplished where resource managers use all cultural practices known to be effective in minimizing pest damage. In considering the need for and possibilities of pest control, forest managers also should be impressed with the need to weight the multiple values threatened by a pest outbreak - wood, water, forage, wildlife and recreation. Before a pest control project is undertaken, it is highly desirable that the public be well-informed in advance of plans, procedures, and expected results.
5. The importance of getting along with people. This could hardly be called a principle but it is an important consideration in forest pest control. Knowledge about controlling pests is of little more than academic value if it is not put to use. This usually involves persuading people to do the things that need to be done and that you want them to do. Getting along with people, therefore, is an important part of pest control. It usually plays a role equally as important as an under standing of pathology, entomology, or forestry. In some cases it is more important. Everything we do is conditioned in large part by the reactions and attitudes of people.
Impact of diseases and insects on American forestry
Forest diseases and insects cause huge losses in the United States. For example, in an average year they kill an estimated 7,300 million board feet of valuable sawtimber. Growth impact, or losses in growth of surviving trees is estimated at 21,200 million board feet. These enormous losses occur despite efforts made each year to check damage by action programs in prevention and suppression.
What is the impact of these losses on United States forestry? Well, for one thing, disease has eliminated the American chestnut, one of our finest hardwoods. Disease also stands a fair chance of eliminating the American elm as a forest component. Among the softwoods, the highly prized white pines can be grown only on selected sites and at considerable cost because of blister rust and white pine weevil control operations. The balsam woolly aphid hangs like the sword of Damocles over our extensive stands of fir. To a greater or lesser degree, every tree species the forester deals with and all the silvicultural steps he uses to bring any tree crop to maturity arc affected by diseases and insects. American lumbermen frequently refer to today's tree harvesting in these words, "We don't make cutting plans. The bugs and the blights make them for us."
Procedures followed in forest pest control
The basic procedures used for controlling forest pests in the United States can be counted on the fingers of one hand - detection, evaluation, prevention, suppression, and eradication. Each is highly important and all are closely interwoven.
Detection. Prompt and through detection is the key to quick and effective suppression. In the United States we now inspect all forest lands for evidence of abnormal pest activity. Inspection is handled in two ways, first by utilizing to the fullest possible extent the observations of the man on the ground, and second by planned inspections of forests from the air or on the ground by trained forest pest control officers.
Evaluation. It is a well-established fact that not all abnormal disease and insect activity in the forest requires control action. Therefore, the immediate and potential significance of each pest situation must be evaluated to determine whether control should or should not be undertaken. Evaluations are of two kinds. First, the pest problem is assessed from the biological standpoint to estimate the likely damage and loss to the forest resource if action is deferred, and to appraise the benefits expected from prescribed control measures. Second, the economics of the situation are analyzed to determine the value of the resource at stake and whether or not there would be favorable cost-benefit returns from suppressive action.
In a biological evaluation, all available information on the biology and ecology of the pest is used as a basis for interpreting situations found to exist in a given infection or infestation. Insect populations and trends are measured, and the potential of diseases to spread and cause damage is analyzed. Estimates are made of the amount of damage the pest will cause if it is not suppressed and of the reduction in loss that can be expected from suppressive action. Measures available for checking the pest are reviewed and the safest, cheapest, and most effective ones are recommended in case the decision favors control action.
When the biological assessment indicates that a pest will persist, intensify, and seriously damage the forest, the second part of the evaluation is taken, namely, the economic analysis. This analysis determines the impact of the pest upon each forest value - timber, wildlife, recreation, water, forage, and scenery - and upon the forest environment as a whole. The objective here is to weigh all impacts, including an assessment of the means available for combating the pest, and reach a cost-benefit judgment.
Evaluations - biological and economic - are made by qualified pathologists, entomologists, foresters, and other scientists. While these evaluations are as good as we can make them, they are seldom as good as we would like them to be. We are striving constantly to improve them.
Prevention. We regard prevention as our first line of defense against forest diseases and insects. Our objective is to incorporate into the management of the National Forests those practices that are known to be effective in minimizing pest damage and to urge managers of other forest lands to do likewise. Unfortunately, in the United States today, there are distinct limitations to our doing all we would like to do in the prevention field. As a matter of fact, there are many gaps in our knowledge of just what to do to avoid disease and insect problems. Nonetheless, we do all that present knowledge and the economic situation enable us to do.
In all cases v here it is possible to do so, forest stands already attacked or likely to be attacked by insects and diseases are harvested. However, timber harvest as a prevention practice also has major limitations in the United States. For example, some affected stands or stands susceptible to pest attack arc inaccessible, some are without current market value, while others are set aside for recreational or other single-uses where timber harvesting is either limited or prohibited. Finally, of course, many pest problems cannot be solved by timber harvest or cultural measures.
Suppression. Destructive forest insects and diseases are brought under control in a number of ways. To the extent that it is possible to do so, parasites, predators and pathogens are relied upon to help keep pest populations in check. Unfortunately, biological controls are often ineffective in preventing outbreaks of forest pests, and usually they operate much too slowly to be of much value in suppressing an epidemic.
Where other methods of control are not adequate to provide the needed degree of pest suppression, pesticidal chemicals are called upon. Taking all our pest problems into consideration, we are forced to rely heavily on pesticides today and we will probably have to continue to do so for many years to come. These materials also have their limitations. For example, they may endanger desirable animal and plant life; they rarely can be counted upon to correct the basic cause of pest outbreaks; and their benefits are often temporary. There is a growing trend in pest control in the United States to integrate chemical, biological, and cultural control measures, so that all measures complement one another. To the extent that this can be done, it usually provides safer, more efficient, and longer-lasting benefits.
Eradication. Most of our control efforts are directed against native forest pests, or against firmly established foreign pests. There is no effort to eradicate such pests. This does not mean, however, that eradication does not have a place in our program. As a matter of fact, complete eradication down to the last spore or last specimen is considered highly desirable in situations where an introduced disease or insect has been detected while it is still confined to a relatively small area and is still in its incipient stages of development, or where it has become firmly established in only a small part of its host range, and it is deemed desirable to keep it out of new territory.
Prompt detection of incipient infestations of newly invading pests is a prerequisite for the success of eradication. Of equal importance are rigid federal and state quarantines to prevent spread while eradication programs are underway or while eradication techniques are being worked out. Concurrently, a suppression program is developed within the generally infested area to reduce pest abundance, thus preventing loss and minimizing the chance of long-distance spread. Eradication, to be successful, requires the closest possible co-operation between federal and state governments and other interested groups. It requires full support of all, and a strong determination to press the eradication campaign with speed and vigor, with no compromise in planning or in following a course of action that will locate and destroy the very last remnants of the pest.
Organization for controlling forest pests
The Forest Service, U.S. Department of Agriculture, is the principal agency in the federal government responsible for handling forest pest control in the United States. Before explaining the Forest Service pest control organization, it would be helpful to review briefly the Forest Service organization itself.
The work of the Forest Service is divided into three major fields of responsibility: protecting and managing the national forests, which total 187 million acres; conducting all federal forestry research; and directing federal co-operative programs enacted by Congress for assisting the states and private owners in protecting and improving state and private forests, and in promoting good forest practices on the 435 million acres of nonfederal forest lands in the United States.
In discharging its responsibilities for these broad national programs, the Forest Service maintains a small staff at its Washington headquarters. It has decentralized the responsibility for carrying out its many activities at ten regional headquarters, 154 national forests, 805 ranger districts, 11 forest experiment stations, one forest products laboratory, and 80 research locations.
In the central office at Washington, D.C., and at regional headquarters, the work of the Forest Service is organized into major functional divisions, such as timber management, range management, wildlife management, water management, recreation management, and protection from fire and from pests. Research activities are grouped into similar functional divisions in the Washington office and at regional experiment stations.
In the Washington office there is a Division of Forest Pest Control and a Division of Forest Protection Research. In addition, pest control units are located in each of our ten regional offices, and insect and disease research scientists are located at each forest experiment station. In some cases, pest control officers are attached to the supervisor's staff on a national forest, and research pathologists and entomologists are also stationed at some of the larger research locations.
The Washington office provides overall direction to survey and control activities on all classes of forest ownership, public and private; develops policy prescribing the circumstances under which control is undertaken and how it will be done; reviews and acts on suppression project proposals; allots funds; inspects field work; prepares and justifies budgetary statements for annual appropriations; and maintains liaison with other forest service divisions and other agencies concerned with pest control.
The Division of Forest Pest Control operates under laws enacted by Congress to protect federal lands from damage by destructive diseases and insects and to assist the states and private owners in protecting their forest lands from these pests. Under these laws, the federal government pays the entire cost of pest control on federal lands and shares from 25 to 50 percent of the cost on nonfederal lands, depending upon the nature of the pest problem.
Regional pest control personnel, consisting of 118 professional entomologists, pathologists, and foresters are responsible for providing pest detection and control service for all classes of forest lands.
Pest control on the national forests is under the direction of district rangers and forest supervisors, with technical leadership and assistance provided by pest control officers at regional headquarters.
Pest control on other federal lands, such as national parks, public domain lands, and Indian reservations, is under the direction of the land managers, with technical assistance provided by pest control personnel of the Forest Service.
Pest control on nonfederal lands is under the direction of pest control units of state organizations, usually in the office of the state forester. Technical and financial assistance is provided the states by the Forest Service.
Entomologists and pathologists at regional headquarters and research workers at the forest experiment stations keep in close touch because their respective spheres of responsibility are closely interrelated. Personnel assigned to survey and control activities are kept currently informed on the latest research findings, and research personnel are kept informed on survey and control problems. The research and nonresearch officers frequently take part in planning, conducting and evaluating pilot tests of promising new materials, methods, or techniques for preventing or suppressing forest diseases and insects.
Federal-state-private co-operation
The pest laws under which the Forest Service engages in surveys and control of forest diseases and insects recognize that pests pay no heed to property boundaries and often attack intermingled properties of different owners over extensive areas. While these laws do not require participation by states and landowners, they do provide for co-operation by affected groups. This cooperation is voluntary, and the Forest Service works out co-operative plans for combating pests well in advance of any specific need for control actions. Cooperation is arranged by memoranda of understanding or by co-operative agreements between federal and state agencies. In these, the roles and spheres of responsibility of each participant are defined. It is the responsibility of the states to arrange needed participation by private owners. Co-operative agreements are supplemented by annual work plans outlining the specific financial arrangements and job assignments during a given year.
The Forest Service also co-operates with nonownership groups who are concerned in one way or another in pest-control ventures, such as federal and state fish and game agencies, quarantine and other regulatory authorities, water pollution officials, recreation and other conservation groups, and health authorities. Co-operation of these groups with the Forest Service is especially important when proposed control or eradication operations involve use of chemical pesticides. In providing for such co-operation it is important to do it well in advance of the time the action needs to be undertaken, in order that arrangements for reviewing all aspects of control along with assessments of side effects can be completed.
Problems in using pesticides for controlling forest pests
As mentioned earlier, pesticides are used extensively for suppressing forest insects and to a lesser extent for controlling diseases in the United States, particularly when cultural or biological measures fail or are unavailable. Our experience shows that when chemicals are applied properly at minimum dosage rates and with adequate precautions, they can be used safely and effectively for controlling forest pests. During the past decade we have applied pesticides by aircraft to some 16 million acres of forest land without significant damage to other values.
We recognize, of course, that certain hazards not fully understood may exist in connection with using some pesticides, especially the persistent chlorinated hydrocarbons. Pesticide residues in small quantities have become widely distributed in air, water, and soil in the United States. The possibilities that minute amounts of these residues in plants and animals might cause long-range impacts to wildlife and human health was widely publicized in the United States in 1963. One of these publications emphasized the threat of a "silent spring" for the nation's bird, fish, animal, and even human populations. This publication and others stimulated numerous investigations into the uses of pesticides, including investigations by Congress. The result of these publications was a rapid accumulation of adverse publicity about the hazards and misuses of pesticides. There was an avalanche of inquiries directed to users of pesticides by a public that had suddenly become alarmed over possible pesticide hazards.
The American public sought reassurance from pesticide users and manufacturers that mankind, his bird and animal friends, and beneficial insects, were not about to be exterminated along with destructive insects and diseases. Inquiries coming to the attention of the Forest Service reached such a volume that for a three-month period it was necessary to devote full time to answering them. This was of critical importance in 1963 because we were confronted with a need to spray aerially 1.7 million acres of forest land to control outbreaks of the spruce budworm, hemlock looper, and other defoliators in 15 states.
The question was raised as to whether to go ahead with or cancel all spraying plans. The United States Forest Service decided to spray because we were convinced that it could be done safely. Never in the history of forest pest control in the United States have more people observed and monitored our work. Aided by the precautions taken in spray application, we not only accomplished our objectives, but did so without significant damage to fish, wildlife, or other values.
Looking back on the developments in 1963, we feel optimistic about the future of pesticides in forest pest control. We think, however, that we can expect some tightening of regulations governing pesticide uses. We also think we can look for expanded research into the unanswered questions surrounding their use and for the development of safer pesticides as well as nonchemical controls for destructive pests. More studies will undoubtedly be made concerning the amounts of chemicals in the air, water, and soil, and their effect on man, wildlife, and fish.
There will be, we are sure, more attention given to educating the public regarding safe uses of pesticides. All these actions should result in a greater safety in the use of pesticides than now exists. We are optimistic that we can carry on successfully even with tightened restrictions.
In conclusion, we would like to re-emphasize that the rate at which losses from destructive forest diseases and insects in the United States will be reduced in the coming years will depend upon: the rate of progress in research; the extent to which old-growth timber is harvested; new developments in the utilization of pest-infested and infected material; the extent of conversion of the wild forest to managed tree farms; and our success in better co-ordinating and tightening up co-operative control among federal, state, and private forest landowners. The most important of these is, we are sure, the rate of our progress in research. Herein lies the key to the problem, for those of us who have responsibility for control can move forward no faster than research can provide the means.
