by
J.G. Mwangi and J.G.D. Ward
Forest Health
Management Centre
Forest Department,
Box 30241, Karura, Muthaiga
Kenya
A new Forest Health Management Centre (formerly known as the Integrated Forest Pest Management Centre) has been created under the Ministry of Environment and Natural Resources in Kenya. The Centre will enhance protection of forests by addressing the problems which cause losses to Kenya's forest resource, Regular monitoring and early problem identification will result in prompt remedial measures. Where knowledge gaps exist, research will be encouraged.
* * * * *
From about 1930 to 1979, pest management in Kenya was carried out by the Research Section of the Forest Department. This Research Section was incorporated into the new Kenya Agricultural Research Institute (KARI) after the split of the East African Community in 1977. In 1986, forestry research evolved from KARI into an independent institute known as the Kenya Forestry Research Institute (KEFRI). KEFRI was placed under the Minister of Research, Science and Technical Training, whereas the Forest Department remained in the Ministry of Environment and Natural Resources.
This separation of forestry functions under two different Ministries resulted in a lack of expertise in the Forest Department in the applied aspects of Forest Insect and Disease Management. Field officers in the Forest Department stopped routine reporting of forest pest status on their districts but pests continued to remain active in the forest.
The most damaging pest outbreak occurred when the cypress aphid, Cinara cupressi, first appeared in Kenya in 1990 and 10 000 ha of industrial cypress plantations were lost. The Government of Kenya was quick to establish a National Aphid Project to coordinate all national activities related to research, information and control of the aphid. This project was funded by the Government of Kenya with assistance from FAO, UNDP and the World Bank. As a part of the Project Master Plan, an operational, integrated forest pest management programme was envisioned. Subsequently, through the FAO/UNDP Project KEN/91/005, a consultant was invited by the Government of Kenya to draft a charter for the establishment of a Forest Pest Management Centre in 1993. The Charter was approved by the government in 1994 but the centre was renamed the Forest Health Management Centre, to address a wide range of problems which affect the health of forests, not just insects such as cypress aphid.
The mission of the Centre is to ensure that healthy forests continue to be grown by enhancing protection and proper forest management practices in Kenya. Industrial plantations presently comprise about 167,000 ha and indigenous forests comprise about 5 million ha of Kenya's forest estate. Most of the indigenous forests have poor stem form and are more useful for water catchment protection, preservation of biodiversity, beekeeping, etc, than for production of timber and other wood based products. Total land area under forest cover is only 3% and is not increasing. Hence, the importance of optimising tree growth by farmers and communities on their lands. The Centre's mission therefore, also covers agroforestry programmes.
The Centre's goals are described in the following sections:
Research findings contained in technical publications are often like a theoretical driving manual for a learner who will not be able move a car even after he memorizes every word that is contained in the manual. A learner driver will need to be shown how to practise the theory before he can drive effectively. Likewise, the Centre will show the Forest Department and others how to make use of this knowledge. Hence, the Centre will act like a bridge between researchers and field officers while enhancing technology transfer.
Perhaps it is important to mention that during the peak of the cypress aphid epidemic, four Kenyans died while treating trees with chemicals using unsafe practices. Additionally, it was also evident that high dosages of chemicals are used in various forest nurseries to control pests. This destroys the natural enemies of such pests.
Regular monitoring of forests will provide information of changes taking place in the forests. This information will be used to develop appropriate standards for forest health and treatment strategies. A crown rating system is one of the first methods of evaluating tree condition that will be used.
Specialists such as entomologists and pathologists are usually invited a address a problem when it is too late. Early detection is important because it would result in early attention being given to the problem.
Identifying the problem enables an appropriate literature survey to be carries out. the survey may produce enough information to allow foresters to effectively handle the problem.
The Centre would identify knowledge gaps and subsequently encourage research scientists to carry out appropriate investigations in order to fill needed gaps in the knowledge.
Gathering and dissemination of all of the latest information on forest health from all the appropriate local and international institutions will be very important because this will result in considerable savings of resources which would otherwise have been spent on unneeded research.
Aerial sketchmapping will be carried out to provide information on the condition of Kenya's forests. In the event of a pest outbreak, information on the extent and intensity of damage will be obtained. Ground surveys would be conducted after aerial surveys are completed. Resultant information will be used to help develop decision support systems for treatment of pest problems.
As an immediate measure, chemical treatment may be used to suppress pests but priority will be given to biological control, introduction of pest resistant varieties and silvicultural tactics used either alone or in combination to reduce pest caused losses.
The Centre intends to train all field officers on safe use of pesticides in conjunction with the Forest Extension Services Division.
The Centre will ensure that all forest stations have a sprayer that is well maintained. Training on light maintenance will be carried out.
Appropriate treatment protocols will be taught to the forest nursery staff. Preventative or remedial treatment will be carried out in nurseries to ensure high levels of production.
Currently in Kenya, there are no appropriate quarantine procedures for plant materials at various border points. This will need to be initiated in order to reduce the risk of accidental introductions of additional exotic pests.
Evaluation of losses are important when taking various pest management decisions. The Centre intends to provide loss assessment data that is due to pests or other factors which cause damage to forests. Loss prediction models will be developed.
The Centre signed a letter of record with the Forest Pest Management Staff of USDA Forest Service in March 1994. Through this letter of record, the Centre can share information and training with counterparts in the United States. The Centre intends to continue to continue collaboration with the International Institute of Biological Control (IIBC).
The Centre intends to continue its collaboration with national institutes such as the Kenya Forestry Research Institute (KEFRI), Moi University, National Museums of Kenya, International Centre for Insect Ecology and Physiology (ICIPE) and also initiate new linkages with the Kenya Wildlife Service and the Kenya Remote Sensing and Monitoring Unit.
by
G.B. Allard, S.T. Murphy and R.K. Day
International Institute
of Biological Control
Nairobi, Kenya and
Silwood Park, UK
In 1991, in response to a series of outbreaks of exotic conifer pests, particularly the cypress aphid, Cinara cupressi, the International Institute of Biological Control (IIBC) was contracted by the Canadian International Development Agency (CIDA) and the Overseas Development Administration (ODA) to implement a programme to assist African national forestry organisations.
The primary objective of the programme is the permanent biological control of cypress aphid, Cinara cupressi. pine woolly aphid, Pineus ?boerneri, and the pine needle aphid Eulachnus rileyi, through the importation, quarantine and release of specific natural enemies.
IIBC has therefore joined with a number of African forest research departments to develop and implement environmentally sound pest management measures, based on biological control. A regional approach has been adopted, because most problems are shared, and cooperation can prevent duplication of effort and maximise resources for research and training.
The second objective of the programme is to strengthen the capacity within national forest research departments to develop and implement biological control and integrated pest management of forest pests. This is being achieved through training, co-operative research and establishment of local biological control facilities.
To fulfil this part of the programme, IIBC has surveyed forest protection problems, infrastructure and needs in nine countries in east and southern Africa. Plans for strengthening forest protection capability have been developed with the appropriate national organisations, and, within funding constraints, these are being realised.
* * * * *
Since the beginning of this century, exotic trees (e.g. pines, cypress, eucalypts) have been introduced into Africa to provide vital supplies of fuel, sawn timber, pulp and other forest products to supplement wood products from the declining indigenous forests.
In eastern and southern Africa industrial and social afforestation programmes have intensified during the last 30 years and a considerable amount of land has been devoted to large and small scale exotic tree plantations, particularly softwoods. From 1965 to 1980, the area of forest plantations in Africa, chiefly consisting of exotic species, rose 86% from 1.4 to 2.6 million hectares (Evans 1982). This intensification of forest planting, particularly of monocultures of exotic species, has created increased opportunities for pest outbreaks.
During most of this century, conifer tree plantations in Africa were relatively free of insect pest problems. This situation has changed markedly in the last few decades with the accidental introduction of four exotic forest aphid pests from the Holarctic region; the cypress aphid, Cinara cupressi (Buckton) (Aphididae: Lachnidae), the black pine aphid Cinara cronartii Tissot& Pepper (Aphididae: Lachnidae), the pine needle aphid, Eulachnus rileyi Williams (Aphididae: Lachnidae) and the pine woolly aphid Pineus ?boerneri Annand (Homoptera: Adelgidae). These exotic aphid pests, free from natural enemies and other control factors that keep them in check in their area of origin, have been able to multiply and disperse rapidly and have caused considerable damage to large areas of forested highlands in eastern and southern Africa.
The cypress aphid is the most damaging of the species with a wide host range including exotic cypresses and indigenous cedars (Cupressaceae). Genera of Cupressaceae attacked by this aphid include Callitris, Chamaecyparis, Cupressus, Cupressocyparis, Juniperus, Thuja and Widdringtonia (Ciesla 1991). Spread of the cypress aphid within Africa has been rapid and within eight years the aphid had moved throughout east and southern Africa; Malawi (1996), Tanzania (1987), Burundi (1988), Rwanda (1989), Uganda (1989), Zimbabwe (1990), Kenya (1990), South Africa (1993). Presence of the aphid in Ethiopia and Zaire is yet to be confirmed.
The three pine aphids are the most damaging of insects found on pines. The black pine aphid is confined to South Africa and has been the target of a successful biological control programme. The pine needle aphid and the pine woolly aphid have a broad host range which includes all of the major industrial pine species grown in eastern and southern Africa. Pine needle aphid is now ubiquitous wherever pine plantations occur and has been recorded from Burundi, Kenya, Malawi, South Africa, Rwanda, Tanzania, Uganda, Zambia and Zimbabwe. Host preference trials carried out in South Africa showed Pinus kesiya to be far the most favoured pine species of those tested and intraspecific differences in susceptibility of pine trees to aphid infestation have been indicated (Merchant 1989). Distribution of pine woolly aphid is limited to Kenya, Uganda, Tanzania, Malawi, Zambia, Zimbabwe and South Africa with unconfirmed reports from Ethiopia. Susceptible pine species include P. kesiya, P. elliottii and P. radiata with P. patula and P. taeda being less susceptible.
Losses in standing volume and annual growth increments caused by the conifer aphids are difficult to quantify but estimates in the range of millions of US dollars have been made. In Kenya alone the losses due to C. cupressi could amount to nearly $ 20 million in lost revenue, while the commercial value of the losses could be as high as $1 25 million (pers. comm., P. Ryan, World Bank).
This paper summarises the work that IIBC has carried out on behalf of the affected countries to assist in control of these aphids through a regional classical biological control project aimed at the identification and introduction of specific, safe and effective natural enemies of the aphid pests from their regions of origin.
The IIBC biological control project has two objectives: first the permanent biological control of cypress aphid, pine woolly aphid and pine needle aphid by national forest research departments in Eastern and Southern Africa: second the strengthening of the capacity within the national forest research departments for the development and implementation of biological control and integrated pest management (IPM) for forest pests, through a programme of training, co-operative research and establishment of local biological control facilities.
Eleven countries are currently involved in the project: Burundi, Ethiopia, Kenya, Malawi, Rwanda, South Africa, Tanzania, Uganda, Zaire, Zambia and Zimbabwe.
The project, which started in 1991, is a collaborative venture being undertaken by IIBC and national forest research departments in Africa with support from a number of organisations in Europe and North America. Funding for the regional component of the aphid biological control project is being provided by the Canadian International Development Agency (CIDA), the Overseas Development Agency (ODA), the Food and Agriculture Organisation of the United Nations (FAO) and the United States Department of Agriculture Forest Service (USDA FS).
The IIBC Regional Biological Control Programme has developed its strategies for a co- coordinated approach to forest aphid biocontrol within the framework of the recommendations from a regional workshop held in Kenya in June 1991 (Ciesla et al 1991). In order to meet the objectives of the project and to set the scene for future developments, IIBC activities have been focused in three areas:
The progress made in each of these three areas is summarized below.
Surveys for specialized insect natural enemies are being undertaken in Great Britain, continental Europe and the USA to cover the extensive distribution of the three aphids. This work is being organised and conducted by the IIBC UK Station; exploratory work in North America is being conducted in collaboration with the United States Department of Agriculture Forest Service and the Canadian Forest Service. National scientists from Malawi and Kenya have been involved in surveying for natural enemies in Europe.
Potential biological control agents have been identified for all three conifer aphid pests. In particular, a hymenopterous parasitoid, Pauesia juniperorum, that attacks the cypress aphid, has been identified and this parasitoid was shipped to the IIBC Kenya Station in 1993/94. Laboratory evaluation studies on this parasitoid have indicated that this species has great potential as a biological control agent. The first field release of this parasitoid was made in Malawi by the Forestry Research Institute of Malawi (FRIM) in June 1994 and first indications of establishment are encouraging. Releases have also been made in Kenya by the Kenya Forestry Research Institute (KEFRI) and IIBC, in September 1994.
Further exploratory work is still being conducted in order to cover the full spectrum of agents that might be available.
This is being undertaken by IIBC from its base in Kenya in collaboration with national scientists. The results from the studies are being used to advise national programmes in the affected countries. Sampling methods have been developed for the cypress aphid and are nearing completion for the pine woolly aphid. Effective rearing methods for these aphids have also been developed. The research findings and recommendations being generated by IIBC are being summarized in a Technical Bulletin series; three bulletins have been produced to date. These bulletins are used as an aid in training courses for forest entomologists and are more widely distributed throughout the region for general information.
The regional biological control programme provides opportunities for collaborative research by participating regional scientists and this collaboration yields several benefits including strengthening the capacity of national institutions to carry out biological programmes in the future.
By supporting and coordinating collaborative research, the project can also increase the value of research results, by avoiding duplication of effort, ensuring standard methods are used, disseminating the findings throughout the region, and by assisting with analysis and publication.
At the IIBC Kenya station, an insectary of about 110m2 was completed in early 1 993 and is now fully operational. The insectary houses cultures of the cypress aphid, pine woolly aphid and Pauesia juniperorum. The screenhouse is intended to supply cultures of biocontrol agents to the region.
Full interactions have been developed with the participating countries and agreement has been reached with the relevant Government departments about the participation of the country in the regional project. Country assessments have been made covering topics such as resources, manpower and training needs for the forestry departments so that they can undertake forest pest management and biological control activities on other pests on a more sustainable basis. Bilateral proposals for external support have been prepared where relevant and country reports summarising the situations in the countries are available.
In most cases, the resources available for forest pest management were found to be inadequate or totally lacking. In view of this situation several courses of action have been taken. First, as an immediate step, on-the-spot advice and training for individuals has been provided and this has taken place in all countries and also during organised visits to IIBC Kenya and UK. More formal training in biological control has been provided through in- country training courses. In addition, a regional training course was held in December 1993, involving all countries.
To assist in infrastructure development, basic equipment (e.g. microscopes, computers and laboratory equipment) and resources for insectary construction, refurbishment and seedling production have been supplied to enable some countries, who have trained personnel but no equipment, to get underway with insect rearing and sampling surveys. The transport problems facing some forestry research institutes and departments have been addressed by support with running costs and/or the provision of motorcycles and bicycles. Countries supplied or having reached agreement to be supplied to date from the regional project include Burundi, Kenya, Tanzania, Uganda and Zambia, and other countries will be receiving help from the regional project in 1994/1995.
The idea of the establishment of a forest pest management network between countries within southern and eastern Africa was discussed and agreed at a conifer aphid workshop organized by the Kenya Forestry Research Institute (KEFRI) in collaboration with FAO, USDA Forest Service and IIBC held in June 1991. The existence of a network in the region would strengthen and enhance the forest pest management capability of each country. IIBC has initiated a number of activities which have helped 'materialize' the notion of a network within the national forestry pest management programmes including: exchange visits of scientists between countries, collaborative projects, and the production of a network newsletter. The first edition of the newsletter was circulated in December 1993 with the objective of disseminating information of mutual interest throughout Africa. The formalisation of this network is to be discussed at this workshop.
The present programme has created a unique opportunity to effect institutional development, while addressing the immediate problem of forestry pest management. This will also strengthen national institutions' capability to address future plant protection problems effectively. Further support from governments, policy makers and donor agencies is now essential to maintain the momentum.
Forest monocultures are always going to be at risk from insect pests and diseases e.g. Leucaena psyllid, Eucalypt borer, Dothistroma needle blight, Sphaeropsis die-back of pines. In view of this, forest pest management needs to become an integral part of afforestation and reforestation programmes. In particular, in the long term, there needs to be a shift of emphasis by the national forestry programmes from "corrective" forest pest management to 'preventative' forest pest management; i.e. to move to a proactive activity rather than a reactive one.
We would like to acknowledge sincerely the Canadian International Development Agency and the Overseas Development Administration, the Food and Agriculture Organisation of the United Nations for their foresight in supporting such an important and previously neglected component of forestry management.
We would also like to thank all of the participating national programmes for their enthusiasm, support and contribution to this programme.
Ciesla, W.M., 1991. The cypress aphid, Cinara cupressi (Buckton) in Africa. In: Exotic aphid pests of conifers - a crisis in African forestry. Workshop Proceedings, Kenya Forestry Research Institute, Muguga, Kenya, 3-6 June 1991. Rome, Food and Agriculture Organisation of the United Nations, pp 33-47.
Ciesla, W.M., J. Odera, and M.J.W. Cock, (Eds), 1991. Exotic aphid pests of conifers - a crisis in African forestry. Workshop Proceedings, Kenya Forestry Research Institute, Muguga, Kenya, 3-6 June 1991. Rome, Food and Agriculture Organisation of the United Nations, 160 pp.
Evans, J., 1982. Plantation Forestry in the Tropics. Oxford; Clarendon Press, 432 pp.
Marchant, L.J.D., 1989. The pine needle aphid, Eulachnus rileyi Williams (Homoptera: Aphididae): pest status in Natal, Republic of South Africa. MSc thesis University of Natal, 197 pp.Odera, J.A., 1991. Pernicious exotic pests affecting forests and forest products in Eastern, Central and Southern Africa. In Exotic aphid pests of conifers - a crisis in African forestry. Workshop Proceedings, Kenya Forestry Research Institute, Muguga, Kenya, 3-6 June 1 991. Rome, Food and Agriculture Organisation of the United Nations, pp 99-105.
by
Daniel R. Kucera, Robert D. Wolfe and
Gerard D. Hertel1
USDA Forest Service
Northeastern Area, State and Private
Forestry
Radnor, Pennsylvania
U.S.A.
Nonindigenous or exotic plant and animal species have been and continue to be a serious threat to the integrity of the forest and rangeland ecosystems of the United States. Historically, introduced forest pests have altered tree species composition, reduced biodiversity, diminished scenic values, and altered wildlife habitat.
The chestnut blight fungus, Endothia parasitica [Murr.] A. and A., Dutch elm disease Ceratocystis ulmi [Buism.] C. Moreau), the European strain of the gypsy moth, Lymantria dispar L., and leafy spurge Euphorbia esula L., are a few of the more commonly known introduced forest and range pests in the United States. The first two are fungus-caused pathogens and are examples of exotic pests that have eliminated significant species, such as the American chestnut, Castanea dentata [Marsh.] Borkh., and American elm, Ulmus americana L.), over much of their original range and in cities and towns. Not only did they change our forests, but they resulted in serious economic loss over a large portion of the country.
The cost of research on these pests, the cost of trying to control them, the loss of forest products and wildlife habitat, and damage to the local economies has been in the billions of dollars. Efforts to suppress or manage introduced pests have cost local, State, and Federal agencies and private landowners additional billions of dollars for control-related activities. For example, during 1980-1993 the Forest Service assisted State and Federal agencies in suppressing populations of the European strain of the gypsy moth in the eastern United States. During that time, Federal and State governments spent $143.4 million dollars on suppression related activities (Twardus and Machesky 1993).
The introduction of exotic pests into the United States began over two hundred years ago and has continued, in spite of exclusion and regulatory efforts to keep them out. In fact, the rate of introductions have increased as a result of increased commerce and tourism among a larger number of nations. This paper reviews organizations and policies dealing with pest introductions and discusses some recent case histories.
The Plant Protection and Quarantine Division of the Animal and Plant Health Inspection Service (APHIS), U.S. Department of Agriculture (USDA), is the agency responsible for preventing the introduction of exotic insects, pathogens, and plant pests into the United States. This agency is also responsible for the detection and eradication of all exotic pests that are introduced into the country. Once a particular pest becomes established to the extent that it becomes impossible to eradicate, however, other agencies such as the USDA Agricultural Research Service (ARS) and Forest Service, as well as agencies in the Department of Interior, become involved in efforts to manage the pest.
When exotic pests affect either forest or range ecosystems in the United States, the Forest Service is one land managing agency that is often involved. As such, Forest Service philosophy has been to vigorously support APHIS efforts to eradicate such introductions when detected. In addition to APHIS, the Forest Service is working with the plant regulatory agencies in Canada and Mexico, to strengthen safeguards against the introduction of exotic forest insects and pathogens into North America.
Specific accomplishments include: completion of risk assessments for proposed importations of raw logs from Chile, New Zealand, and Russia; assistance to APHIS in the development of the first U.S. quarantine regulations for the importation of raw wood products into the United States; scientific review for APHIS of proposed treatment protocols for importation of wood products; leadership of a new joint project with Mexico and Canada under the North American Forestry Commission to identify organisms world-wide that pose a high risk to North America; harmonization of U.S. and Canadian gypsy moth management policies; and assistance to APHIS and the States of Oregon and Washington in the successful eradication in 1992 of the Asian strain of gypsy moth (AGM). The Forest Service is working with APHIS and the North Carolina Department of Agriculture to eradicate another introduction of Asian gypsy moth discovered in 1993. The Forest Service and APHIS both worked with the Russian government to plan and establish an AGM monitoring program around Russian far eastern ports. This system is providing an early warning of outbreak conditions in Russia so that increased regulatory measures on shipping can be instituted to protect North America.
In 1991, Washington State Department of Agriculture detected introductions of the AGM at eight sites around the port of Tacoma, Washington. In addition, moths were also detected in the Portland, Oregon, area. More than 25 moths were caught. These moths were introduced into the United States via ships or cargo from Russian eastern ports. Both the Oregon and Washington sites were successfully eradicated with two to three aerial applications of the bacterial insecticide, Bacillus thuringiensis (Bt), over 133,417 acres (54,015 hectares) in 1992 and 1993, at a cost of over $US 20 million.
On July 4, 1993, a container vessel, the U.S.S. Advantage, arrived from Germany and docked at the military ocean terminal at Sunny Point, North Carolina. On July 6, the ship was found to be contaminated with gypsy moth pupae, adults, and egg masses. In addition, thousands of moths, some of which were female moths, were seen flying on and around the ship. It was determined that the moths were the Asian strain and had originated in Lorsch, Germany, where the military cargo had been stored under trees before shipment. In spring 1994 the port of Wilmington, North Carolina, and surrounding susceptible forest land (144,000 acres or 80,972 hectares) was aerially treated at a cost of over $US 10 million. In both situations APHIS, the agency with regulatory authority, implemented eradication efforts against the introductions.
To detect gypsy moth and other pest introductions, APHIS maintains a nationwide port survey and inspection effort. All gypsy moths captured in traps in or around the ports are sent to the APHIS Otis Methods Center in Massachusetts for DNA screening to determine if the moths are the Asian or European strain. The European strain was introduced into the Boston, Massachusetts, area from Europe in 1869 and is now found generally throughout all or portions of 16 eastern States. The screening process involves DNA analysis for established markers common to the Asian or European strain. Screening results of moth captures in 1994 show the following:
Since most of the eastern United States is already infested with the European strain of the gypsy moth, why all the concern about the AGM introductions? First, the female AGM is a strong flier and has the potential to rapidly infest new areas (USDA Forest Service 1992). Second, it survives and feeds aggressively on some conifers, such as larch, making forests in the western United States more susceptible to rapid infestation and damage. Third, the AGM often lays its egg masses on the hardwood leaves, which fall from the trees in October. Winter (December through February) snows cover the fallen foliage and egg masses, thereby providing greater protection and survival of the Asian strain, than for the European strain.
Eradication of the AGM must be initiated as soon as possible after detection. The size of the eradication area is based on the anticipated distance that AGM females may fly from the point of introduction to susceptible forest type, a distance of up to 25 miles (40 kilometres). In addition, such eradication projects usually involve two to three applications of insecticides followed by intensive trapping to determine the effectiveness of the project. While eradication of AGM is expensive, the rapid spread and potential damage that the insect may cause to the forest resources and local economy is estimated in the billions of dollars. As introductions of the AGM increase in and around U.S. port areas, additional methods of controlling this pest may be needed.
WHEN DISCOVERED AND AREA INFESTED - The common pine shoot beetle, Tomicus piniperda L. is thought to have been introduced into the Great Lakes States on dunnage from Europe. Dunnage is material, usually rough cut lumber, placed under or among goods and as bracing to prevent shifting or movement of cargo in the hold of a ship. A population of the shoot beetle was discovered in a Christmas tree plantation near Cleveland, Ohio, in July 1992. Since then it has been found in 11 6 counties in six Great Lakes States (Ohio, New York, Pennsylvania, Illinois, Michigan, and Indiana) and in 8 counties in Canada.
The spruce bark beetle, Ips typographus L., another exotic pest, was detected at the port of Erie, Pennsylvania, in July 1993 (Cavey and Passoa 1993). The insect is believed to have emerged from a large pile of dunnage at the port. Upon detection, the dunnage was burned at the site. Another specimen was collected in Camden, New Jersey, in 1994.
HOSTS - The common pine shoot beetle is native to Europe and possibly Asia and is considered a serious bark beetle pest of pines (Haack and Kucera 1993). The beetle feeds on the shoots of pine thus damaging growth. In weakened trees it will feed on the main trunk. Of tree species tested in the United States, the pine shoot beetle was found to attack and reproduce on all southern pines, northern pines, and in the West on ponderosa pine, Pinus ponderosa Dougl. ex Laws., and lodgepole pine, Pinus contorta Dougl. ex Loud. In the Lake States it prefers Scotch pine, Pinus sylvestris L., especially in Christmas tree plantations.
The spruce bark beetle is one of the most serious and aggressive pests of Eurasian origin. The insect prefers Norway spruce, Picea abies [L.] Karst), but also attacks other spruces. The insect has the ability to attack and kill relatively vigorous trees, introducing a pathogenic blue stain fungus that predisposes infested trees to beetle attack. In addition, the beetles have an effective aggregating pheromone, which allows the beetles to "mass attack" selected trees (Bakke 1991).
ACTIONS TAKEN - APHIS has placed a quarantine on Christmas trees, logs, and nursery stock from infested areas, to reduce the spread of Tomicus piniperda. Currently logs cannot be moved from infested counties to uninfested counties, unless the logs are treated in some way. If the insect spreads to southern pine plantations, the result may be significant damage and economic losses. The Forest Service has started research on the pest's life cycle, host preference, and behaviour, in addition to control treatments. Thus far, T. piniperda has not entered mature pine stands.
In addition to the above tactics the cooperation of landowners is being encouraged to suppress beetle populations by reducing slash, maintaining a clean nursery or plantation, using trap logs as necessary to monitor populations, and, as a last resort, chemical control. To determine if the spruce bark beetle was established in and around the Erie, Pennsylvania, port, the Forest Service assisted APHIS personnel in placing pheromone-baited Lindgren funnel traps in a systematic grid throughout portions of three surrounding counties. No additional beetles were collected in the traps in 1993 and 1994. A beetle was trapped, however, near the port of Camden, New Jersey, on April 26, 1994. Traps were placed in a systematic grid in and around the Camden port, but no additional insects have been captured.
A more recent concern has been the rapid spread of exotic weeds both in the Eastern and Western United States. In the West weeds are primarily a range problem, while in the East they are an urban-wetland problem. For example, purple loosestrife, Lythrum salicaria L., and mile-a-minute weed, Polygonum perfoliatum L., are of increasing concern. Purple loosestrife is a wetland weed found from northern Aroostook County, Maine, all the way across the United States and into Canada (U.S. Congress 1993). Environmentalists fear that the black-crowned night heron, Nycticorax nycticorax L., has been all but eliminated in the northeastern United States due to replacement of native plants in the heron's habitat by loosestrife.
An even more striking plant is the mile-a-minute weed, which is commonly called tearthumb (it's stems have thorns as well as the midrib and margins of leaves). Some natural park areas in the East are being overrun by this introduced plant. For example, the weed has covered one third of Valley Forge National Park (where General George Washington wintered and trained his troops in the Revolutionary War against Britain) near Philadelphia, Pennsylvania. This exotic weed is a prolific seeder and the seeds are attractive to birds. As it moves southward it could become a perennial rather than an annual as it is in Pennsylvania. Its rate of growth is 6 inches per day (15.2 cm per day), and second only to that of another introduced pest, kudzu, Pueraria lobata [Willd.]).
Due to the seriousness and potential for damage, the Forest Service is planning several meetings in the near future to develop strategies to deal with the growing list of exotic weeds. Nevertheless, where there are few or no National Forests, as in the eastern United States, little is being done to address the problem. Urban areas in particular are just beginning to be affected.
With increasing world trade and a concomitant increase in world imports, there is a need to strengthen the present system to prevent the introduction of plant pests in or on logs or lumber and other unmanufactured wood articles. A systematic exclusion of plant pests is vital to protect U.S. forests and other resources from damage.
Risk assessments have been completed on the importation of Monterey pine, Pinus radiata D. Don), coigue, Nothofagus dombeyi Mirb. [Oerst.]), and tepa, Laurelia phillipiana Loos., logs from Chile; Monterey pine and Douglas-fir, Pseudotsuga menziesii [Mirb.] Franco), logs from New Zealand; and potential pests of imported timber from the Federal Republic of Russia.
As a result of these assessments logs entering the United States from Chile will have to be debarked and fumigated. In addition, logs must be kept segregated from timber arriving from other sources and processed within 60 days. Similar regulations apply to logs from New Zealand.
For logs from Russia the regulations are much more stringent, because a large number of deep-wood borers have been found, especially in larch. Logs in transit will not be allowed above deck on a vessel unless mitigative measures have been applied to preclude the escape of pests. Any quarantine treatment would have to be supervised by an APHIS employee. Next, timber products must be free of soil before departure from Russian ports, with clearance given by APHIS personnel (USDA APHIS 1991). Lastly, logs from Russia must also receive a heat treatment (Table 1).
Exotic conifer plantations form the backbone of the timber and fuelwood industries in Kenya and other East African nations. These forests are at risk from three introduced aphid species, some of which are native or most probably native to the United States or
TABLE 1
STATUS OF LOG IMPORT RISK ASSESSMENTS
|
EXPORTING |
PEST RISK |
MITIGATION |
STATUS OF |
|
Russia |
Severe |
Heat treatment |
No imports |
|
New Zealand |
Significant |
Debarking Fumigation |
Imports |
|
Chile |
Significant |
Debarking Fumigation |
Imports |
North America. Losses in Kenya alone are estimated at $100 million and eventually could exceed several billion dollars as other countries are affected. The most serious of these aphid pests is the cypress aphid, Cinara cupressi (Buckton), which was discovered in East Africa in 1986. It spread rapidly over a wide range of hosts and poses a threat not only to the forestry sector but also to native cypress and juniper commonly used for hedgerows and as ornamentals--especially for shade (C.A.B. International 1993). Insecticides are ruled out: first, due to the cost; and second, due to the insect's habit of clustering under bark flaps and dense foliage where insecticides are unable to penetrate.
In cooperation with the International Institute of Biological Control (IIBC) and FAO, the Forest Service began a nationwide exploratory survey in 1 991 in hopes of finding the aphid and its parasites and predators. As a result of the survey nine species of Cinara aphids were found along with promising parasites and predators. In addition, a colony of Cinara spp. from Colorado has now been established at IIBC headquarters in Silwood Park, England, and can be used to test promising parasites and predators.
Recently, Sanidad Forestal, with the Mexican Department of Agriculture, found Cinara aphids south of Mexico City. This is exciting news as they were found on native Mexican cypress, which is also the most favoured plantation tree in Kenya. For this reason the Forest Service and IIBC are looking for native parasites and predators in southern Mexico.
This trip will provide a great opportunity to find potential control agents, as parasites are sensitive and survive best on aphids that feed on preferred host plants.
Explorations for natural enemies are planned in other countries. In addition, the Forest Service is providing training and equipment to help Kenya to assess their problem and to develop solutions. Recently, a Forest Health Centre was established in the Forest Department in Kenya.
The loblolly pine mealybug, Oracella acuta Lobdell, is a native pest throughout the southeastern United States. It was first described from an undetermined species of pine from Ocean Springs, Mississippi, and later from the Houston, Texas, area (Ferris 1950).
In 1988, O. acuta was accidentally introduced into the People's Republic of China (PRO. Since this first discovery infestations have expanded to over 741,300 acres (300,000 hectares) of pine forest, and the mealybug is now considered to be a major threat by Chinese scientists. Attempts at trying to control this pest with native parasites and predators have failed. Thus, the Chinese have urgently requested U.S. cooperation and assistance.
In the United States several natural enemies help keep the mealybug populations at endemic levels. Most abundant are two parasitoids, Acerophagus coccois (Hymenoptera: Encyrtidae) and Allotropa spp. (Hymenoptera: Platygasteridae). Several predators have been found as well (Reardon and Berisford 1994).
Forest Service objectives are to raise significant amounts of parasites and predators for eventual release in China. This will be accomplished by dramatically increasing native populations of O. acuta. It has been discovered that certain pyrethroid insecticides adversely affect natural enemies and dramatically increase mealybug populations. Therefore, aerial applications of a pyrethroid insecticide will be used to create local outbreaks in loblolly pine plantations in Georgia and Texas. Once mealybug populations build up spraying will cease, natural enemies will be allowed to build up, and infested shoots will be collected and brought to a laboratory. Natural enemies will then be reared and identified. The final step will be to collect adult parasitoids and parasitized female mealybugs for shipment to China. U.S. scientists should be on hand for the first releases in China and also to help establish rearing facilities.
The number of exotic pests introduced into the United States is expected to grow as foreign travel and trade increase, especially with Russia and its former satellite countries. To counter this threat, the United States needs to expand its application of regulatory authorities and develop a greater ability to respond to new introductions. The United States must also develop improved methods of controlling those exotic pests that have become established before they threaten native ecosystems. The use of chemical insecticides, fungicides, and herbicides will provide the first line of defense in initial eradication efforts. Once an exotic pest becomes established, however, their long term management will depend on biological agents either developed or imported from the pests' native ecosystems. The United States must also expand its knowledge of potential exotic pests that may be introduced through international trade, and through international cooperation seek to exclude such pests from shipments before they arrive in the country.
Bakke, A., 1991. Using pheromones in the management of bark beetle outbreaks. in Baranchikov, Yuri N., W.J. Mattson, F.P. Hain, T.L. Payne, (eds), Forest insect guilds: Patterns of interaction with host trees; 1989 August 13-17; Abakan, Siberia, U.S.S.R. Gen. Tech. Rep. NE-153. Radnor, PA, U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station, pp 371-377.
C.A.B. International, 1993. International Institute of Biological Control: Annual Report 1993. ISBN 0-85198-828-8. Wallingford, U.K. 93 pp.
Cavey, J. and S. Passoa, 1993. Pest alert: Possible new introduction-European spruce bark beetle: lps typographus (L). NA-TP-18-93. Radnor, PA: U.S. Department of Agriculture, Forest Service, Northeastern Area State and Private Forestry and Northeastern Region. 2 pp.
Ferris, G.F., 1950. Atlas of the scale insects of North America, series V: The Pseudococcidae (Part 1). Stanford, CA: Stanford University Press, pp 112-113.
Haack, R. and D. Kucera, 1993. Pest alert: New introduction-common pine shoot beetle, Tomicus piniperda (L.). NA-TP-05-93. Radnor, PA, U.S. Department of Agriculture, Forest Service, Northeastern Area State and Private Forestry and Northeastern Region. 2 pp.
Reardon, R. and C.W. Berisford, 1994. A cooperative agreement proposal for rearing "Biological control agents for the loblolly pine mealybug, Oracella acuta Lobdell." [Unpublished report]. Morgantown, WV: U.S. Department of Agriculture, Forest Service, Northeastern Area State and Private Forestry.
Twardus, D.B. and H.A. Machesky, eds, 1993. Gypsy moth news. Morgantown, WV: U.S. Department of Agriculture, Forest Service, Northeastern Area State and Private Forestry. October.
U.S. Congress, Office of Technology Assessment, 1993. Harmful non-indigenous species in the United States. OTA-F-565. Washington, DC: U.S. Government Printing Office. September: 391 pp.
U.S. Department of Agriculture, APHIS, 1991. An efficacy review of control measures for potential pests of imported Soviet timber. Misc. Publ. No. 1496. Washington, DC: U.S. Department of Agriculture, Animal and Plant Health Inspection Service. 28 pp.
U.S. Department of Agriculture, Forest Service, 1992. Gypsy moth exotica: A U.S./Canada chronicle. Hamden, CT: Northeastern Forest Experiment Station. Number 1, January: 5 pp. [Unpublished newsletter]
1Presented by Gerard D. Hertel
