Australia and New Zealand
Africa
Europe
India and Pakistan
South and Central America
North America
Summary and conclusions
This session of the Symposium provided a unique opportunity for forest entomologists and forest managers from most major geographical regions of the world to become acquainted with each other's forest insect problems, to hear something of the strengths and weaknesses of the various forest entomological services, and to receive recommendations and opinions on how best these services might be improved or developed. Originally invitations were extended to 20 regions. Most major regions of the world were represented, but it was unfortunate that little information was received from such important areas as the U.S.S.R., China, southeast Asia, and Japan. This leaves a serious gap in this review of the world situation.
Some 19 reports were received and discussed during the Symposium. It is not possible to summarize each of these individually in the space available and the salient points have therefore been drawn together on the basis of geographical regions representing more or less common forest insect and ecological features. These are not discussed necessarily in order of importance.
Forest entomological research in Australia is of limited extent, reflecting the relatively small contribution that forestry makes to the economy of the country. However, forestry is increasing in significance and there are signs of forthcoming stronger support for research on forest insects. Australia has 12 million hectares of native forest and 200,000 hectares of planted conifers. It currently employs 6 to 8 professional forest entomologists, and, until recently, research was concentrated on insects of converted timber rather than those of living trees. While a large number of native forest insects are known, the list is probably far from complete. The need for an Australian forest insect survey has been stressed at many Commonwealth forestry conferences but as yet no central body exists with the resources necessary for such an undertaking. Forest insect problems are the responsibility of several state departments, while at the federal level, forest and timber insect research is carried out by the Divisions of Entomology and Forest Products of the Commonwealth Scientific and Industrial Research Organisation (CSIRO), and by the Commonwealth Forestry and Timber Bureau.
In New Zealand, which has 5.8 million hectares of native forests and 350,000 hectares of planted conifers, research and investigations in forest entomology are entrusted to the Forest Research Institute with a staff of three professional entomologists and supporting technicians at Rotorua. A Forest Biology Survey, established in 1955, and modeled on the Canadian Survey, consists of 12 observers located throughout the country. They inspect exotic plantations only and take samples of both insect and disease organisms. The Survey provides an early warning system for insects and diseases, while research is directed mainly toward the development of silvicultural and biological control measures. Inspectors of the New Zealand Forest Service inspect all timber imported and exported. It is largely because of these inspectors that a greater number of dangerous timber insects have not become established in New Zealand.
In Australia, native forests include many species of high commercial value and research is divided between their entomological problems, those of conifer plantations, and those of converted timber. Major problems are associated with outbreaks of defoliating insects on eucalyptus. Non-eucalypt species are damaged primarily by shoot-boring insects. Softwood plantations (Pinus spp.) experience minor damage from introduced bark beetles and case moths, and there is evidence that some native insects are adapting to pines. Great concern has attended the discovery of Sirex noctilio because of the threat that this species offers to large commercial plantations, particularly to those in South Australia. Major current research relates to Sirex and phasmatid problems.
In New Zealand, little entomological work has been carried out in native forests and concentrated on the exotic conifers, especially on Pinus radiata, the main timber producer. The major problems at present recognized in these plantations are Sirex noctilio, defoliators, mostlyg eometrids and tortricids, Hylastes aster on regeneration, several species of weevils and Lepidoptera causing damage in nurseries, seed insects, a number of wood borers, and several species of sapsucking insects, although the latter are not considered of major importance.
The entomological situation in New Zealand has no serious problems, at present, but it is precarious because of the even-aged monoculture of P. radiata and too few entomologists. Two spruce species cannot be grown partly because of a spruce aphid and the best exotics are P. radiata and Douglas fir.
In both New Zealand and Australia there is felt to be a great need for more co-operation in the international timber trade to prevent the exchange of dangerous insects. The exotic pine plantations are considered to be vulnerable to the introduction of serious pests that could be brought in from overseas. The thought was also expressed that short-term international exchanges of postgraduate students would be of value in broadening viewpoints and experience and providing a basis for more international cooperation.
Conditions in a belt running across northern and central Africa were covered by reports on French- and English-speaking West Africa, and East Africa. Borers of living trees, both indigenous hardwoods and exotic softwoods, are common throughout this belt. Attention was drawn to two main problems encountered in West Africa which remain unsolved: the mahogany shoot borer, Hypsipyla robusta, and the iroko gall louse, Phytolyma lata, as well as ambrosia beetles. Present control methods are mainly silvicultural, but action soon becomes limited owing to economic considerations.
Conditions peculiar to Gambia, Sierra Leone, and Nigeria were presented in a statement. Initially, forest policies in all three countries aimed to encourage the growth and regeneration of a wide variety of indigenous species. In later years this policy was changed to place emphasis first on the establishment of indigenous species, and finally to introduce exotics planted as uniform stands, particularly in the northern savanna areas. Few indigenous trees have proved successful in plantations, especially because of depredations by various lepidopterous shoot borers. As in most of West Africa, mahogany shoot borers, Hypsipyla spp., are a serious problem. Ambrosia beetles, several of which attack living trees, damage and downgrade the wood. The several species of exotics that have been planted, Eucalyptus being an important one, are subject to attack from termites, scale insects, and a few shoot borers. Other than termites there are no known insect pests in West Africa that have limited the planting of exotics.
Research into pests of forest trees in West Africa has been limited. Surveys of insect pests of indigenous and exotic trees in plantations and nurseries have been made in Nigeria and are being continued. The suggestion was made that FAO might provide more technical assistance and there was a plea for work at an international level on shoot borers, particularly Hypsipyla, since this is a worldwide problem in the tropics.
The East African report was concerned mainly with Kenya, Uganda, and Tanzania, with minor reference to Zambia and Malawi. As in West Africa, a major problem is shoot borers of indigenous hardwoods. Hypsipyla spp. are a pest, but more important are Lamiid beetles of the subfamily Tragocephalini. A cerambycid Oemida gahani, is a major pest of exotic cypress plantations. Ambrosia beetles are also important pests. Despite large areas of exotic plantations of conifers and Eucalyptus spp., only minor outbreaks of defoliators have been observed.
Interterritorial surveys and research are carried out by the East African Agricultural and Forestry Research Organization entomologists in conjunction with territorial entomologists. In all there are four entomologists in East Africa to do this work. Surveys are directed mainly against borers and defoliators of plantations, while research is concentrated on Oemida, termites, and ambrosia beetles. On the international scene, exchange of information on problems of a similar nature was encouraged, and combined investigations of shoot borers were recommended. More frequent meetings of forest entomologists were encouraged.
In South Africa, the principal insect pests are associated with exotic forests, consisting mainly of conifers, but eucalypts, black wattles, and poplars are also grown. The several forest districts are widely separated. With the exception of black wattles and some eucalypts, insect attack is not continuous and rarely severe. Except for a few introduced species, the forest insects attacking exotic plantations are indigenous. There are about five forest entomologists in South Africa.
The indigenous bagworm is the most serious pest of black wattle and it is sometimes necessary to resort to aerial spraying to prevent severe defoliation. An introduced curculionid was brought under control by the introduction of a parasite from southern Australia. There are records of Sirex having been intercepted in South Africa, but none has been found in living forests.
Some foreign species of insects have been found in plantations of exotics. The danger of introducing foreign pests into South Africa is appreciated and a policy of prohibiting the entry of trees to prevent this is rigidly enforced. Continuing surveys of plantations to locate new introductions or outbreaks is also considered to be most important.
Europe has such a diversity of climates, forests, and working groups that it is preferable to treat the several regions separately. Accordingly, the European situation is discussed under the following headings: Nordic countries, United Kingdom, Western Europe, Central Europe, Eastern Europe, and Mediterranean countries.
NORDIC COUNTRIES
Within this region various types of forests occur ranging from predominantly deciduous woods in the South to mainly coniferous forests in the north. Defoliator insects are of relatively minor importance, but outbreaks occur occasionally. Hylobius abietis has developed into a serious pest of seedlings all over the Nordic countries, and for a number of years in succession spruce forests have been attacked by Dendroctonus micans. Damage by secondary insects, notably bark beetles and various cerambycids, is a chronic problem on sawn timber and pulpwood.
Owing to the wide variety of forest types in the Nordic countries, insect problems are of many kinds and close co-operation has been established between entomologists in Denmark, Finland, Norway and Sweden. There are 5 institutions dealing with forest entomology and between them they employ about 19 forest entomologists. Organized co-operation began in 1955, when work on the pine weevil, Hylobius, was initiated. Since then, 15 meetings have been held. The meetings and organization are strictly informal. At the meetings insect situations, programs, and progress statements on studies are presented.
UNITED KINGDOM
Forests in Britain occupy some 7.5 percent of the land area, mostly single species plantations of Pinus sylvestris and introduced conifers. Government forestry in Britain started in 1919 and entomological experience on the whole is therefore limited to nursery and polestage crops. As the crops reached about 35 years, insect problems began to develop. In felled areas, Hylobius and Hylastes are common pests of transplants. Adelges spp. have proved to be serious pests of young planted Abies, and have precluded the wide use of this valuable volume-producing genus. Bupalus piniarius has attained outbreak proportions. Some sawflies, bark beetles, and ambrosia beetles are considered potential pests.
Research is mainly carried out by the Research Branch of the Forestry Commission. Other institutions engaged in pertinent research are Aberdeen University, Rothamsted, Edinburgh University, and the Nature Conservancy. Insect surveys are not a feature of forest entomology in the United Kingdom, but special surveys are carried out for specific insects.
In the field of international co-operation there was indicated a need for long-term records on insect abundance to aid epidemiological studies, distribution maps of major pest species, and more meetings between entomologists from different countries.
WESTERN EUROPE
The only formal report from western Europe covered forest entomology in the Netherlands. In recent years the yields from forest crops have not been able to keep up with increased costs because timber values have hardly gone up and land values have increased with the growing demand for space in this heavily populated country. On the other hand, there is an ever increasing need for recreational forests. This suggests that mixed forests of high aesthetic value should be developed and that the cost should take into account recreational as well as financial returns. In forests of this type, chemical control should be used sparingly because of possible adverse side effects.
A strong plea was made that forest insect survey organizations should be set up in all countries, and their findings published to enable workers to compose a broad overall picture of insect conditions.
Although there was no formal report from France, it was pointed out during discussion that in the past there has been little interest in forest entomology in France, but that this attitude is now changing. Although there is little tree mortality caused by insects, there is concern about insect-caused loss of growth of poplars and pines.
CENTRAL EUROPE
Switzerland, Austria, and the Federal Republic of Germany were covered in a report for this region. The original hardwood forests of the lower part of Central Europe have changed considerably in the past two centuries due to increased planting of commercially superior monocultures of conifers, such as spruce and pine. However, these have proved particularly susceptible to insect attack. Severe outbreaks of pine and spruce defoliators have posed serious problems for several decades. Although used only as a last resort, between 1925 and 1951 more than 280,000 hectares of German forests have been sprayed from the air. The current trend is for re-establishing a more natural forest composition to reduce the hazards of insect damage.
The detection and appraisal of large-scale insect outbreaks is the responsibility of regular insect surveys conducted on a regional basis. Insect collections are sent for identification to regional Institutes of Forest Protection, three of which are located in the Federal Republic of Germany, one in Austria, and one in Switzerland. Long-term population dynamic studies of defoliators are in progress to provide a better understanding of the underlying causes of insect outbreaks.
Exchange of information is maintained through annual meetings of the German Society for Applied Entomology. However, it was suggested that information compiled by regional groups should be more widely distributed and that there be closer co-ordination of some basic research projects on population dynamics.
EASTERN EUROPE
The report from eastern Europe included Eastern Germany, Poland, Czechoslovakia, Hungary, Romania, and Bulgaria. From the aspect of forest entomology these countries represent an interesting region with a great variety of forest types and corresponding insect problems. The northwestern parts of this region were influenced by ideas of German forestry, so monocultures of even-aged conifers are dominant. This influence decreases to the southeast where the forests have been left more natural.
In the monoculture forests the major pests are a number of defoliators, bark beetles, and plantation pests. In the mixed beech/fir forests, a complex of insects causes die-back of fir. Oak forests in the Carpathian Mountains suffer periodic outbreaks of the gypsy moth, and oak in the lower Danube and Prut are also damaged by gypsy moth, scale insects, and a number of other species. Gypsy moth is also a problem on oak in the Bulgarian mountains, The ambrosia beetle, Trypodendron lineaium, has become a serious general pest.
Problems in eastern Europe are investigated at a number of institutes. There is one of these in Eastern Germany, two in Poland, two in Czechoslovakia, one in Hungary, and one in Bulgaria. Most problems are studied from the Standpoint of chemical and biological control, and population dynamics.
Forest entomologists from the institutes in eastern Europe meet each year to discuss problems and research results. There is a feeling that it would be useful to establish closer contact with similar entomological groups in west European countries. It was suggested that the new IUFRO Working Group in Forest Entomology could play an important role in developing international exchange of information.
MEDITERRANEAN COUNTRIES
In the eastern Mediterranean countries of Greece, Turkey, Cyprus, and Israel, the main problems are ambrosia and bark beetles, nursery grubs, and defoliators and shoot moths of pines. Matsucoccus is a potential threat to pine forests. Oaks and poplars are attacked by a number of defoliators.
In the western Mediterranean, especially in Spain, three species of defoliators are important, and two species of defoliators and shoot and tip insects are of concern in the extensive planted pine forests.
The importance of the Matsucoccus problem in southern Europe was stressed. There are several species and it was suggested that a co-ordinated approach be taken in studying their biologies and control.
There are few forest entomologists and well-equipped laboratories in this region. To date, the entomologists have been concerned with surveys and extension work.
It is of interest to note that during the Symposium the Mediterranean entomologists banded together to form a permanent regional working group with the object of meeting periodically to exchange information, and, if possible, develop co-ordinated research and survey programs.
In India, the most important forest insect problems are concerned with the growing of teak, which has a number of defoliators, and Shorea robusta (sal), and with the protection of freshly felled timber and stored wood from infestation by wood-boring insects. Insecticides have not been used on a large scale. Insect material collected by forest officers and other government departments all over India was systematically examined, special attention being paid to the classification of immature stages of Coleoptera and Lepidoptera. A large collection, containing over 20,000 species and over 2 million specimens has been built up. Courses in forest entomology are given at the Indian Forest College and the Northern Forest Ranger College.
In West Pakistan, the growing of Shisham trees in irrigated plantations is made difficult by a defoliator, and wood produced in plantations and elsewhere is attacked by powder post beetles. In East Pakistan, felled logs of "Sundri," growing in the mangrove forests, are attacked by an ambrosia beetle and several other kinds of beetles. Many of the insect problems in both East and West Pakistan are not well known. In view of the increased demand for timber, forest protection has become important. In order to evaluate losses to the forests caused by insects, a survey of insect fauna was started in January 1963, through financial assistance from the United States.
Unfortunately only one report - from Argentina was received to cover the South American situation. South America has a large number of forest pests and its main problems are of two kinds:
(a) species attacking plantations, composed largely of exotic pines and eucalyptus;
(b) insects of forest products.
Plantations are difficult to establish because of some species of ambrosia beetles that attack living trees. Pinus radiata plantations are defoliated by several Lepidoptera. Borers, mostly cerambycids, are the main problem in forest products.
A special report on a severe outbreak of the southern pine beetle in Honduras demonstrated the need for the initiation of forest protection services in Central and South America. More than 20 million cubic meters of high quality pine have been killed, and the remaining stands are threatened with destruction. This is the most extensive and most damaging epidemic of the southern pine beetle that has ever been recorded. It is too large and moving too rapidly for the available manpower to cope with, and it is probable that the epidemic will have to run its course.
Forest entomology throughout South and Central America is generally not highly developed. There is a lack of biological knowledge of insects and a serious shortage of forest entomologists. For example, there is only one qualified forest entomologist in Argentina. There are insufficient funds available to train staff, but two forestry schools in South America may eventually produce some entomologists.
This review covers Mexico, the United States, and Canada. In North America, insects rank high among all causes of timber mortality. Although their importance varies between different parts of the continent, the most destructive groups of insects are bark beetles, defoliators, terminal feeders, seed and cone insects, wood borers, wood products insects, and sucking insects. For many years a large segment of the North American forest economy has been supported by virgin stands. As these are harvested there is a corresponding increase in area of second growth stands, the establishment of more and more plantations, and the development of seed orchards, seed production areas, and superior parent trees. These have produced changes in the emphasis of forest entomology. There have been no signs of a reduction of impact caused by forest insects and, indeed, the impact can be expected to increase.
From the standpoint of volume of timber killed, bark beetles perhaps rank first in importance and, in general, they are most damaging in western North America, from Canada through the United States into Mexico. Among these are beetles of the genera Dendroctonus, Ips, and Scolytus. As a group, the defoliators rank second in importance. Budworms, loopers, tussock moths, tent caterpillars, and several other species kill many trees and reduce the growth rate of others. The boreal forests of Canada in particular seem predisposed to several serious in sect pests, the spruce budworm, Choristoneura fumiferana, being a prime example. A third group consists of insects that feed on the terminal parts of trees and these are particularly important as they damage young trees in plantations. Because of the increase in plantations, the demand for quantities of high quality seed is increasing rapidly and has focused attention on the, destruction caused by cone and seed insects.
The problems created by indigenous pests is compounded by the steady appearance of insects from Europe that have proved to be very destructive in their new environment. Outstanding examples are the larch sawfly, European spruce sawfly, balsam woolly aphid, European pine shoot moth, and the winter moth.
Research in forest entomology has been underway in the United States for about 60 years. The U.S. Forest Service currently has more than 80 scientists, based at 10 forest experiment stations, engaged in basic and applied research. Research is also conducted at a number of universities and by a number of private timber companies. The U.S. Forest Service also employs about 80 entomologists who are engaged in forest insect surveys and control work. This organization works closely with the states and private industry in co-operative aspects of surveys and control. Many of the state forestry services are adding forest entomologists to their staffs and some have formed their own survey organization. Forest pest action committees have been formed in many parts of the country to consider insect problems and plans for control.
Recognition of the importance of forest entomology in the United States has resulted in a rapid increase in financial support by federal, state, and private agencies, and has produced a shortage of forest entomologists. This, in turn, is reflected in the greater emphasis being given by more universities on providing better training in forest entomology and related subjects.
Since the appointment of the first full-time entomologist in Canada about 50 years ago, the science and practice of forest entomology have developed and expanded at a significant rate. Forestry is of extreme importance to the economy of Canada, and its extensive forests are attacked by many pests. There are about 120 forest entomologists in Canada. Three are associated with provincial government departments, three teach at universities, one is a consultant, and the remainder are employed by the Canada Department of Forestry. The complexity of forest insect problems has led provincial authorities, who are constitutionally responsible for the administration of forest resources, to depend primarily on the Federal Department for detection and evaluation surveys, research, and technical advisory services.
The emphasis placed on continuing detection and appraisal surveys is perhaps the most distinctive feature of forest entomology in Canada. The survey has been in progress since the midthirties and is operated on an integrated national basis. The research program may be considered under three headings:
(a) broad faunal or bio-taxonomic studies often con ducted within the framework of the survey program;
(b) problem-oriented projects of a bio-ecological nature that often emphasize a strong quantitative base;
(c) discipline-oriented projects providing general sup port or establishing principles.
Mexico has a shortage of trained manpower to cope with its forest insects. Bark beetles constitute the main problem and losses in the past few years have constituted 50 percent of all those caused by insects and diseases. Salvage, sanitation measures, and chemicals have been used to combat these outbreaks, which have brought home the need for a control organization and trained personnel.
Timber owners and managers in North America are much less willing than in the past to accept insect-caused losses as inevitable. Chemicals play an important role in insect control and will probably continue to do so, but intensive research programs are in progress to determine the underlying causes of insect outbreaks and to explore the greater use of biological and silvicultural methods to reduce insect damage.
The North American Forestry Commission, formed in 1961 under the auspices of FAO, includes a special working group in forest entomology and pathology. A program of mutual interest to the United States, Mexico, and Canada is currently being developed. Three international work conferences have been active for some years in the eastern, central, and western parts of North America. These usually meet once a year and have provided good contacts between workers from the United States and Canada. Although not primarily international in nature, the Southern Forest Insect Work Conference also exchanges information with the other groups.
Several important features and needs relating to the international world situation in forest entomology emerged from the reports presented and from discussions relating to the establishment of a permanent Working Group on Forest Entomology within IUFRO. Most of these, were formally recognized in resolutions approved by the final plenary session of the Symposium.
Possibly one of the most significant revelations was the great imbalance in distribution of forest entomologists throughout the world. This ranges from well-staffed and well-equipped services in some countries, with comprehensive balanced research and survey programs, to an acute shortage of forest entomologists in other important forest regions of the world. On the other hand, it was made abundantly clear that there are many serious forest insect problems throughout the world not receiving adequate attention. In order to help correct this imbalance there is a challenge to well-endowed countries to provide means for general and specialized training to forest entomologists from developing countries. It was also suggested that countries needing help and advice could be aided by the appointment of a qualified forest entomologist to the Forestry and Forest Products Division of FAO. More rapid progress might also be made if close co-operation were developed with agricultural or other appropriate research organizations, particularly in regions of limited resources.
There also emerged from the reports evidence of the desperate need for more information on the identification, biology, ecology, and control of important pests in many parts of the world.
The possible spread of noxious forest insects is a cause for concern, especially in those countries having large areas of even-aged monoculture exotic forests. International trade has and will continue to distribute insects that are a potential hazard to the forests of the countries receiving them. Any reasonable steps to reduce this movement to a minimum are obviously worthwhile.
It became clear from the regional reports that a great deal of information of the status and distribution of insects and new introductions does exist but much of it does not reach a form that can be widely distributed or appreciated. In view of the plea made by many delegates for the exchange and dissemination of information, it is hoped that countries having such information will recognize its international value.
It was learned that there exist several international regional working groups. Good examples are those operating in the Nordic countries, eastern Europe, and North America. Their advantages were extolled and it was felt that as the network of such groups increases, the problem of worldwide communication and cooperative effort will diminish. It is of particular interest that during the Symposium forest entomologists from the Mediterranean countries arranged to form a working group and meet regularly.
The Oxford Symposium provided a concrete and satisfying example of the benefits that can be derived from close collaboration between FAO and IUFRO, organizations which are mutually complementary in many respects. The advances made in the organization and definition of a working group on forest entomology within IUFRO should provide a better basis for future collaboration. This should prove useful in lessening losses caused by forest insects and to this end it was suggested that another Symposium be organized within the next decade.
