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5. Plant Quarantine - Ram Nath


Introduction
Plant quarantine as a national service
Complementary role of plant quarantine
Pest/pathogen detection techniques
Salvaging of infested/infected material
Examination of pest/pathogen risk in plant introduction
Quarantine regulations
Plant quarantine system in India
NBPGR's responsibilities
National coordination
International/regional cooperation
General considerations
Summary
References
Appendix I. Important pathogens and pests intercepted on introduced seeds/planting materials at NBPGR*

Introduction

Insects, mites, nematodes, fungi, bacteria, viruses, MLOs and other organisms are known to attack various crops of economic importance. These pests and pathogens not only reduce the quantity but also spoil the quality of the produce to a considerable extent. About crop losses due to the pests and diseases, legendary wheat pathologist, E.C. Stakman (1969) said, 'Weeds, insect-pests and plant diseases reduce the potential agricultural production in the U.S. by 23 percent. The potential food that has been aborted, spoiled or damaged would be enough to feed at least 75 million human beings. In Europe, it could feed Norway, Sweden, Finland, Denmark, Netherlands, Belgium, Czechoslovakia, Switzerland and Portugal or the four Scandinavian countries and the Great Britain. In Africa, it could feed Congo, Tanzania, Kenya, Ethiopia and Sudan'. Indeed, the magnitude of losses caused by various pests and diseases to our crops is frightening. The situation in most of the developing world may still be worse. All out efforts are, therefore, required to atleast reduce these losses through proper management of crops and through pests and disease management.

Various methods of pest/disease control are: exclusion, eradication, protection, therapy, resistance, and biological control. Exclusion or 'keeping out' is fundamental to the concept of plant quarantine while eradication methods are employed to eliminate a newly established pest/pathogen. Plant quarantine may, therefore, be defined as 'Rules and regulations promulgated by governments to regulate the introduction of plants, planting materials, plant products, soil, living organisms, etc. with a view to prevent inadvertent introduction of exotic pests, weeds and pathogens harmful to the agriculture or the environment of a country/region, and if introduced, to prevent their establishment and further spread'. Plant quarantine is thus designed as a safeguard against harmful pests/pathogens exotic to a country or a region.

Plant quarantine as a national service

From time to time, the introduced pests/pathogens have devastated crops and even created famine conditions in different parts of the world. The Ireland famine of 1845 was the result of an almost total failure of the potato crop due to the introduction of the late blight pathogen (Phytophthora infestans) from Central America. Introduction of powdery mildew (Uncinula necator), Phylloxera and the downy mildew (Plasmopara viticola) in quick succession about the middle of 19th century from America, virtually annihilated the grape vine industry of France. The chestnut blight (Endothia parasitica) was introduced into the US on the nursery stocks imported from the Orient about 1906. Within 25 years, the American chestnut was almost exterminated as a forest tree causing an estimated loss of 1000 million US dollars. In Sri Lanka, coffee was replaced by tea as a plantation crop because of the widespread epiphytotics of coffee leaf rust (Hemileia vastatrix) in 1868. Also, about 20,000 hectares of coconut plantation was devastated by the introduced coconut leaf minor (Promecotheca cumingi) during the late 1960s.

In India also, several pests and diseases got introduced from time to time, some of which, like late blight of potato, banana bunchy top, bacterial blight and streak diseases of paddy, have since become widespread. Some others like golden nematode and wart disease of potato and downy mildew of onion are still localized in certain parts of the country.

The above examples only highlight the risks involved in inadvertent introduction of serious pests/diseases alongwith the planting material imported without adequate safeguards. Plant quarantine can provide such safeguards. Plant quarantine measures aim at providing protection to the agriculture of a country or region against the likely ravages of alien pests/pathogens should they get introduced and established. These measures are of particular importance and relevance to countries like India whose economy is largely based on agriculture. Quarantine not only helps to ward off the threats of exotic pests, but also aim to eliminate and prevent further spread of pests/pathogens (both indigenous and introduced) with restricted distribution within the country (domestic quarantine). According to Mathys (1975), 'Government quarantine offers services which are beyond the capabilities of individual beneficiaries or that are difficult to obtain in some otherway at a lesser cost'. Thus, plant quarantine, in real sense, serves as a national service by preventing the introduction of exotic pests/pathogens/weeds and their further spread. However, such endeavours could succeed only with the active support of all-the administrators, general public, farmers, scientists, communication media, customs and others.

Complementary role of plant quarantine

Plant genetic stocks are a global resource meant for the welfare of humanity. Plant introductions could be in the form of new crops or new varieties for crop diversification, or germplasm in the form of primitive landraces or wild/weedy relatives of crop plants. Germplasm from centres of origin and crop diversity may possess valuable genes for resistance against pests/pathogens, high yield, early maturity, cold, drought or salinity tolerance and quality traits like increased oil, protein contents, etc. Plant quarantine services are charged with the responsibility of preventing entry of hazardous pests, pathogens and weeds, but to deny entry to the valuable genetic resources would be against national interest. These activities are meant to help agricultural development and they are complementary to each other. Too much conservatism on the part of plant quarantine officials and too liberal an attitude on the part of plant introduction officials/breeders would be harmful. Plant quarantine officials must strive to provide adequate safeguards to allow smooth flow of germplasm resources in a healthy state. They should also try to ensure that the germplasm, when received in quarantine station, is processed promptly and that the delays in release, if any, are purely due to biological considerations alone. At the same time, circumvention of plant quarantine must be avoided at all cost even if it means delay in release or rejection of certain materials based on biological consideration. The two should work in unison as members of a single team. Together they should decide the type, quantity and source of the material, and also the required quarantine safeguards. The plant quarantine officials should conduct research on developing sensitive and reliable methods of detection and salvaging treatments, or find alternatives to permit introduction of even high risk genera, if introduction of such materials is in the national interest.

Pest/pathogen detection techniques


Generalized tests
Specialized tests

Success or failure of plant quarantine measures would depend, to a great extent, on the ability of plant quarantine officials to detect pests and pathogens that may be associated with the introduced planting material. For quarantine purposes, techniques should be sensitive enough to detect even trace infections. This is particularly important in case of pests/pathogens with very high multiplication rate like certain pycnidial fungi, downy mildews, bacteria and also viruses when the insect vectors are efficient.

A wide variety of pests and pathogens (insects, mites, nematodes, fungi, bacteria, viruses, viroids/MLOs, spiroplasma, etc.) and weeds are the objects for quarantine consideration. Similarly, planting material also may be introduced in a variety of forms, i.e., true seed, corms, bulbs, rhizomes, suckers, runners, budwood, scions, cuttings and rooted plants. Therefore, detection techniques would vary depending on the type of material, the host species and the type of pests/pathogens involved. Many a times, more than one technique would have to be used. Detection techniques may broadly be classified into two groups: (a) generalized tests which would reveal a wide range of pests/pathogens; and (b) specialized or specific tests which are used to detect specific pests/pathogens (Neergaard, 1977b).

Generalized tests

A very widely used method is the inspection of dry seed with the naked eye or under the low power of microscope. This method would reveal a wide range of free moving insects, their eggs and larval stages, mites on or with the seed, weeds, soil, infected/infested plant debris, fungal fructifications like sclerotia, smut and bunt balls, nematode galls, discoloured or deformed seeds mixed with seed; oospore or bacterial crusts, acervuli, pycnidia, sclerotia and even free spores of rusts, smuts and many other fungi on the seed surface. Examination of dry seed under UV or NUV light may reveal infections of certain fungi and bacteria through emission of fluorescence of different colours. Examination of seed washings may reveal surface contamination by rusts, smuts, downy mildews and a large number of other fungi.

Most commonly used incubation methods for the detection of fungi are the common moist blotter and agar tests wherein seeds are incubated on these media for a specific length of time (generally about a week) at a suitable temperature under alternating light and dark cycles. These two media reveal a wide range of internally seed-borne fungal and some bacterial pathogens in a wide variety of crops. Seedling symptom test and the growout test are quite versatile and reveal the symptoms produced by any category of plant pathogens including fungi, bacteria and viruses. Growout test is the simplest of the tests extensively used for the detection of viruses. However, some viruses may be carried symptomlessly in the plant and, therefore, it should be used in combination with other tests like indexing on indicator test plants and serology.

Specialized tests

Insects

X-ray radiography has been used very successfully all over the world for the detection of hidden infestation (with no apparent sign of infestation on the seed surface) of insects, particularly seed infesting chalcids and bruchids. Seed transparency test (boiling the seeds in lactophenol to make them transparent) may also be used for the detection of hidden infestation and extraction of the insects for identification. X-ray radiography is also very effective in salvaging infested seed lots.

Nematodes

For the detection of seed-borne nematodes, seeds are soaked in water for about 24 hours. This makes the nematodes active, which then come out of the seed into the water, or the seeds may be teased out with the help of forceps and a needle and examined for detection of nematodes under a stereo microscope. In rooted plants, the accompanying soil and plant debris may similarly be soaked in water and nematodes may be extracted for identification using nematological sieves or tissue paper.

Fungi, bacteria and viruses

Serological tests are very effective for the detection and identification of viruses and bacterial pathogens and are being used in various plant quarantine stations with great success. Phage-plague technique is still more sensitive for bacterial pathogens as even strains of bacteria can be identified. Indicator test plants are also very helpful as they may reveal pathogenic races within a species of a fungus, bacterium and specific strains within a virus.

Modifications of the generalized incubation tests (agar and blotter tests) have also been used for the detection of specific plant pathogens. Deep-freezing blotter test and 2,4-D blotter test are very efficient for detection of black-leg pathogen (Phoma lingam) in crucifer crops. Potato-dextrose-oxgall agar is useful for the detection of Septoria nodorum in wheat while PCNB agar is a selective medium for detection of Fusarium species in cereals.

In the case of vegetative propagules, laboratory methods may suffice for the detection of insects and mites, nematodes, majority of fungi and certain bacteria. However, for the detection of systemic fungal pathogens, bacteria, viruses, viroids and MLOs, isolation growing for a season or a year or more in quarantine glass-houses/net-houses is required. Availability of glass-houses/net-houses in large number is an expensive proposition, but the quarantine safeguards afforded by them to any country are worth that expenditure.

Salvaging of infested/infected material


Fumigation
Heat treatment
Chemical treatments
Tissue culture

Once a pest, pathogen or a weed has been detected in the introduced planting material, quarantine officials must make all efforts to disinfect/decontaminate the material and make it available for further exploitation in the country without undue delay. Such an effort on the part of quarantine officials would help to restore a positive image to plant quarantine. However, it may be kept in mind that treatments, which only reduce the inoculum, may be acceptable for general agricultural practices, but they are not acceptable in plant quarantine. For quarantine purposes, tolerances are zero and, therefore, no residual inoculum of exotic pests/pathogens must remain. Fool-proof eradicative treatments are required to be employed before release of the planting material from quarantine.

Fumigation

Fumigation of the material under atmospheric or under reduced pressure has been found acceptable as a quarantine treatment against insects and mites. Fumigants like methyl bromide, HCN, phosphine and EDCT (ethylene dichloride + carbon tetrachloride mixture) are commonly used.

Heat treatment

Hot water treatment or hot air treatment are also used in quarantine for eradication of insects, mites, nematodes, fungi, bacteria and viruses. The basic principle involved is that treatment temperature should be sufficiently high to kill the associated pest/pathogen but not the host. However, in most cases, margin of safety is very narrow and, therefore, the temperature should be very accurately controlled. Some recommended hot water treatments (Kahn, 1977) are:

1. Against nematodes: Flower bulbs, 44° C for 240 min; chrysanthemum, 48° C for 25 min; potato tubers, 45° C for 5 min;

2. Against insects and mites: Narcissus bulbs, 44° C for 180 min; strawberry runners, 46° C for 10 min;

3. Against viruses: Grape vine, 45° C for 120-180 min; sugarcane setts, 50° C for 120 min.; potato tubers, 50° C for 17 min;

4. Against fungi: Celery seed, 50° C for 25 min; wheat seed, 52-54° C for 10 min;

Lambat et al. (1974) reported eradication of Phoma betae in sugarbeet seed by hot water treatment at 50° C for 30 min. Hot water seed treatment has also been reported to eradicate certain bacterial pathogens like black-rot pathogen (Xanthomonas campestris pv. campestris) in crucifer seeds at 50° C for 30 min; bacterial blight of cluster bean (X. campestris pv. cyamopsidis) at 56° C for 10 min (Srivastava and Rao, 1963); and bacterial blight of sesame (X. campestris pv. sesami) at 52° C for 10 min (Rao and Durgapal, 1966).

Chemical treatments

Chemicals may be applied as dust, slurry, spray or as dip. It should be ensured that dosage of chemical should be enough to eradicate the inoculum but should not kill the host and the chemical should not be hazardous to personnel handling the treated seed. Treatment should be given on arrival and only after ascertaining the health status of the material. The choice of the chemical and dosage to be used should be made depending upon the pest/pathogen involved. Seeds treated at origin are not only difficult to examine but are hazardous to inspect also. Heavily treated seed, which makes inspection difficult, should be denied entry (Neergaard, 1977a).

Tissue culture

Tissue culture as a safeguard in quarantine has been advocated by Kahn (1979). This method reduces the pest/pathogen introduction risk in two ways: (i) the size of the consignment is very much reduced since the introductions are represented by meristem tips, excised buds or embryos, and (ii) the aseptic plantlet system has built-in pest/pathogen detection capability. All insects, mites, nematodes and most fungi can be eliminated. Symptoms on young seedlings, and growth of the organisms on the agar medium, if any, may be visible through the transparent culture tubes, and these could be discarded. Tissue culture in combination with thermotherapy and chemotherapy is an excellent safeguard from quarantine angle. However, certain systemically infecting pathogens like rusts, downy mildews, bacteria, viruses, viroids and MLOs, may still get transported. Therefore, as an additional safeguard, the tissue culture material could be passed through post-entry quarantine isolation growing and indexed/tested for the suspected pathogens. Indeed, tissue culture technology provides an exciting prospect for large scale exchange of genetic stocks with very little pest/pathogen introduction risk.

Examination of pest/pathogen risk in plant introduction

Analysis of pest risk in plant introduction is essential to decide as to whether a particular planting material could be permitted entry or not. Such risk analysis provides sound biological basis to decide quarantine policies. The attitude towards 'entry status' of a material may be liberal or conservative depending on the risks involved in its introduction. If risks are low, quarantine would be liberal in permitting the entry. However, if risks are very high, the material may be denied entry. Whether an introduced pest could establish, spread and become serious, depends on three factors viz. (i) availability of susceptible host in abundance; (ii) ability of the introduced pest/pathogen to multiply and spread rapidly; and (iii) availability of favourable environmental conditions. Agricultural practices and the pest/pathogen management strategies in the country of introduction are also important. However, the host-pathogen-environment interactions are very complex and it is not always easy to understand them. As such, many a times, our predictions about risks involved and quarantine importance of a pest may go wrong.

Organisms of quarantine importance are the exotic pests/pathogens, which are considered to pose serious threat to agriculture and environment of a country or region, and include races and biotypes of indigenous pests and pathogens. Any pest risk analysis should take into account the benefits that are likely to accrue from the introduction of the planting material concerned and also the costs of quarantine inspection, treatment including detention in the post-entry quarantine facility and the cost of eradication, should an exotic pest gets established. Pest risk analysis should also consider factors, such as availability of trained personnel, efficacious detection techniques, treatments at the point of entry quarantine, knowledge about the life cycle of the pest, existence of races and strains, world distribution, modes of transmission, factors favouring establishment and spread of pests/pathogens, availability of safeguards (necessary manpower resources, chemicals and equipment to contain and eradicate the pests), and adequacy of the survey and surveillance programme.

Quarantine regulations

Plant quarantine regulations are promulgated by the national and the state governments to prevent the introduction and spread of harmful pests and pathogens. Plant quarantine will be justified only when the pest has no natural means of spread and when they are based on biological considerations only, i.e., pest/pathogen introduction risks and the available safeguards.

In general, risks are more with the introduction of vegetative propagules than with true seed. In case of true seed, risks are more with deep-seated infections than with the surface borne contamination of pests/pathogens. Again, risks are far greater with pathogens like viruses, downy mildews, smuts and many bacteria carried inside the seed without any external symptoms. When vegetative propagules are introduced, rooted plants, and other underground plant parts like rhizomes, suckers, runners, etc. carry higher risks than budwood, scions and unrooted cuttings. In any case, bulk introductions are always risky as thorough examination and treatment in such cases is very difficult and planting area is far too large to prevent the establishment and spread of the introduced pest/disease.

Based on these factors, plant quarantine regulates the introductions as follows:

1. Complete embargo/prohibition: When the pest risk is very high, the safeguards available in the country are not adequate and, therefore, import is prohibited.

2. Post-entry quarantine: The risk is very high but adequate safeguards in the form of post-entry isolation growing facilities are available.

3. Restricted: Pest risk is not high and import permit is required stipulating conditions for entry, inspection and treatment.

4. Unrestricted: Import permit is not required, and material may enter without restriction.

While formulating quarantine regulations, local conditions like crop spectrum and environmental conditions are also to be considered. Since quarantine regulations are designed to break the life cycle of the pest/pathogen involved, the presence of alternate or collateral hosts in the country of import and their introduction should also be taken into account.

Plant quarantine system in India

Plant quarantine activities in India are carried out under the Destructive Insects and Pests Act (DIP Act) of 1914, and the rules and regulations framed from time to time thereunder by the Govt. of India (Anonymous, 1975). Seed was not covered under the DIP Act until 1984, when the Govt. of India brought forward a comprehensive 'Plants, Fruits and Seeds (Regulation of Import into India) Order, 1984' which came into force in June 1985 (Anonymous, 1985).

With a view to provide the farmers the best planting materials available in the world for maximising productivity per unit area and to encourage the private seed industry in India not only to meet the internal requirements but also to develop export potential for high quality planting materials, the Government of India anounced a 'New Policy on Seed Development' in September 1988. The new policy covers the import of seeds/planting materials of wheat, paddy, coarse cereals, oilseeds, pulses, vegetables, flowers, ornamentals and fruit crops; procedures for their import and the related plant quarantine procedures/requirements.

This policy also states that absolutely no compromise shall be made with the requirements of plant quarantine procedures to prevent entry into the country of exotic pests, diseases and weeds detrimental to Indian agriculture. Therefore, to meet the plant quarantine requirements in respect to the provisions of the new seed policy, the Govt. of India brought forward, through Gazette Notification, the updated Plants, Fruits and Seeds (Regulation of Import into India) Order, 1989 (Anonymous, 1989).

The main features of the existing plant quarantine regulations in India are as follows:

1. No consignment of seeds/planting materials shall be imported into India without a valid 'Import Permit', which is to be issued by a competent authority, to be notified by the Central Government from time to time in the Official Gazette.

2. No consignment of seeds/planting materials shall be imported into India unless accompained by a 'Phytosanitary Certificate', issued by the official Plant Quarantine Service of the source country.

3. All consignments of plants and seeds for sowing/propagation/planting purposes shall be imported into India through land customs station, seaport, airport at Amritsar, Bombay, Calcutta, Delhi and Madras, and such other entry points as may be specifically notified by the Central Government from time to time, where these shall be inspected and, if necessary, fumigated, disinfested/disinfected by authorised plant quarantine officials, before quarantine clearance.

4. Seeds/planting materials requiring isolation growing under detention, shall be grown in post-entry quarantine facility approved and certified by the Designated Inspection Authority (DIA) to conform to the conditions laid down by the Plant Protection Adviser to the Govt. of India.

5. Hay, straw or any other materials of plant origin shall not be used as packing material.

6. Import of soil, earth, sand, compost, and plant debris accompanying seeds/planting materials shall not be permitted. However, soil can be imported for research purposes under a special permit issued by the Plant Protection Adviser to the Govt. of India.

The DIP Act empowers the Central Government to make rules for regulating the import of seeds/planting materials into India and also the movement of the materials from one State to another within the country. The State Governments are also empowered to enact rules/regulations to regulate the movement of materials from one region/area to another within a State.

The Directorate of Plant Protection, Quarantine & Storage, headed by the Plant Protection Adviser to the Govt. of India, is primarily responsible for enforcing the quarantine rules and regulations framed under the DIP Act in the country. For this purpose, plant quarantine and fumigation stations have been established at various international airports, seaports and land custom stations where the incoming consignments are inspected, fumigated or otherwise disinfested/disinfected before release to indentors. Consignments of plants/seeds for sowing/planting/propagation purposes, however, can only be imported through Amritsar, Bombay, Calcutta, Delhi and Madras quarantine stations, where facilities in respect to well equipped laboratories, quarantine green-houses and trained scientific and technical manpower are being strengthened to adequately meet the quarantine needs. Quarantine and fumigation stations under the Directorate of Plant Protection, Quarantine & Storage handle bulk imports for commerce and for planting.

NBPGR's responsibilities

As the National Bureau of Plant Genetic Resources (NBPGR), New Delhi has been designated as the national nodal agency for exchange of germplasm material of agri-horticultural and agri-silvicultural crops for research purposes in the country, it has also been entrusted with the quarantine responsibilities in respect to germplasm of these crops. The Director of NBPGR has been empowered to issue 'Permits' for import of seeds/planting materials for research purpose.

NBPGR has a separate Division of Plant Quarantine to meet the quarantine requirements in respect of the germplasm materials being exchanged through it. The Division has trained scientific and technical staff representing the disciplines of entomology, nematology and plant pathology, well equipped laboratories, green houses and post-entry isolation growing field facilities to discharge its quarantine responsibilities efficiently. In case of certain crops, after laboratory examination at NBPGR, the exotic material is passed on to the specific crop-based institutes for post-entry isolation growing, before it is released to the indentors. These institutes have established adequate post-entry isolation growing facilities and required expertise is also available with them. These are Central Potato Research Institute, Shimla; Central Tuber Crops Research Institutes, Trivandrum; Central Tobacco Research Institute, Rajahmundri; Sugarcane Breeding Institute, Coimbatore; and Central Plantation Crops Research Institute, Kasaragod. NBPGR has established a regional Plant Quarantine Station at Hyderabad to fulfil the quarantine requirements of the International Crops Research Institute for Semi-Arid Tropics (ICRISAT), Directorate of Rice Research and other research organisations in the region. It is also proposed to establish quarantine facilities for temperate fruit crops at NBPGR's Regional Station, Bhowali and an off-shore Quarantine Station at Port Blair in the Andaman Group of Islands for vegetatively propagated tropical crops. During the last 12 years or so, a large number of exotic insects and mites, plant parasitic nematodes, plant pathogens and weeds have been intercepted from the imported germplasm materials, many of which are of major quarantine significance and are not yet known to occur in the country (Appendix I). While processing the germplasm for quarantine clearance, all out efforts are made to salvage the infested/infected materials so that valuable exotic germplasm could be made available in a healthy state for exploitation in crop improvement programmes in the country.

National coordination

Most of the plant material enters the country as air cargo or air mail parcels. Passengers going abroad also bring seed/planting material with them. The New Seed Policy now permits private enterprises to introduce more material in certain cases under 'Open General Licence'. Bulk consignments for consumption or sowing are brought by ships, and small research consignments through air freight or post. Therefore, the customs department, postal department, the International Airport Authority and Port Authority of India are also involved. Various research institutes under the Indian Council of Agricultural Research (ICAR) and the Council of Scientific & Industrial Research (CSIR) systems, agricultural universities, state departments of agriculture and the private individuals/agencies are the ultimate users of the introduced germplasm material in crop improvement programmes.

Very effective linkages among all the government agencies are required so that while the introduced planting material is made available to the user clients without undue delay, all the required quarantine safeguards are observed to prevent introduction of foreign pests and diseases. The customs department, postal department, the International Airport Authority and Port Authority of India should ensure that the consignments/post-parcels containing seeds/planting materials are cleared promptly and are sent compulsorily to the plant quarantine services. The consignments should never be released directly to the users. A 'Plant Quarantine Declaration Card', similar to the 'Customs Declaration Card' should be introduced for passengers travelling to India. Any planting material declared or ceased by customs department must be handed over to the plant quarantine officials for inspection and clearance. Officials of customs/postal departments should be made aware about the importance of plant quarantine through regular refresher courses. All international airports/sea ports/international post offices should have plant quarantine counters alongwith the customs counters:

Various research institutes and agricultural universities can also contribute a great deal in this respect. They may develop some limited post-entry quarantine facilities in the form of quarantine net houses/glass houses and the material, at least indented by them, could be grown in post-entry quarantine under the supervision of plant protection scientists. The users of the introduced material, whether they be from the research institutes, universities, agriculture departments or private individuals/agencies, could also contribute a lot in the smooth flow of planting material. They should always try to observe the plant quarantine regulations (requirement for import permit, phytosanitary certificates, etc.). Request for planting material from abroad should be channelized through appropriate authorities. For example, all requests for germplasm for research purposes should be made to the Director, National Bureau of Plant Genetic Resources, New Delhi alongwith details of the material required, source country, name and address of the supplier etc., if available. Proper linkages, coordination of the efforts and cooperation among the concerned agencies would go a long way in smooth flow of material with required quarantine safeguards.

International/regional cooperation

Plant quarantine, while being national in execution, is international in character. Therefore, international/regional cooperation is very necessary for achieving the objectives since plant genetic resources are a world resource meant for the welfare of the human race as a whole. Cooperation on the following lines would greatly help in safe exchange of germplasm materials.

1. Consortium of plant quarantine stations: It is an excellent concept proposed by Kahn (1977) to facilitate the exchange of genetic stocks and scientific information at international/regional level. Any material passing through a plant quarantine station will have very low pest/pathogen risk. The material so generated should be exchanged with other plant quarantine stations promptly, before it is distributed locally and gets contaminated with local pests/pathogens. Several quarantine stations working independently may be processing the same material (same crop or even same variety) at each station. Under the proposed consortium concept, different quarantine stations would undertake the processing of different materials (several accessions of the same crop or a group of crops at each station) and then share the material. This would avoid duplication of efforts, reduce costs of processing and more material would be available with adequate quarantine safeguards. In the same spirit, scientific information (detection techniques, treatments, distribution of pests/pathogens) and antisera for sero-diagnosis of viruses and bacteria could be shared by quarantine stations of different countries.

2. Establishment of central seed health testing laboratories: At present, thousands of seed samples of a variety of crops are being exchanged by different countries for breeding purposes and for conducting multilocation international trials. This has exposed many countries, particularly the developing ones, to the hazards of serious and new seed borne pests/pathogens. Sometimes, the volume of material may be so large that it is not physically possible for a quarantine service to process it with any degree of surity during the time at its disposal before the planting date. In many countries, seed health testing facilities may not be existing or they may be inadequate. Neergaard (1977c) proposed the concept of establishing a few central seed health testing laboratories well equipped with required facilities and trained personnel. These may be coordinated with regional genebanks or international centres, but should be independent of the organisation for whom they are working. Such an arrangement would lower pest risk to a considerable extent and avoid duplication of efforts, thus reducing costs of processing. Plant quarantine services of different countries will have faith in such laboratories and will accept their certification.

3. Third country I intermediate quarantine: The concept of third country quarantine is another example where international cooperation could play an important role in safe transfer of plant genetic resources. This is particularly helpful for transferring high risk tropical/sub-tropical plant genera from one country to another. The material could be grown, tested/indexed for hazardous plant pests and pathogens in a temperate country without much risk because either the possible hosts are not present there or the environment is unfavourable for their establishment. Some centres which have been providing third country quarantine facilities for transferring genetic resources include Sub-tropical Horticulture Research Station, Miami, USA for cocoa, coffee, rubber and tea; University of Reading, UK for groundnut; and Institute Nazionale Per Piante de Legno, Torino, Italy for cassava.

4. Biogeographical regions: The concept of biogeographical regions proposed by Mathys (1975) is an example of regional cooperation. The eight biogeographical regions proposed for effective quarantine are separated by natural barriers like sea, high mountains and deserts, making pest/pathogen dissemination extremely difficult so long as the exchange of genetic resources is judiciously regulated. Accordingly, all countries in such a region must have common quarantine regulations since the larger the land mass covered by the same set of regulations, the greater is the protection afforded to the agriculture of the region. Based on this concept, countries of the ASEAN region have come to an official level understanding and have formulated common set of quarantine regulations to protect the region against alien pests/pathogens. Understanding on the same lines among SAARC countries along with Afghanistan and Burma would be very useful in protecting the agriculture of the entire region. Such an arrangement will reduce duplication of efforts and operational costs. Countries like Sri Lanka and Maldives or even some islands of India (Andaman group of islands) could even serve as third country quarantine for temperate, high risk genera. SAARC countries have already developed cooperative programmes in many crops and quarantine could be incorporated in this agreement.

General considerations

Indian agriculture has made phenomenal progress during the last two and a half decades or so. This has largely been possible due to the introduction and utilisation of superior germplasm in various crop improvement programmes by Indian breeders. To sustain the tempo of this accelerated agricultural growth, it is necessary that the valuable plant genetic resources continue to flow into the country. At the same time, it is also important that exotic pests, pathogens and weeds do not gain entry while introducing exotic germplasm or other planting material. This could be achieved through effective implementation of plant quarantine measures. Plant quarantine can be effective only if it is based on sound scientific considerations. Pest/pathogen introduction risk only should be the guiding principle of our national quarantine policy.

Following suggestions to users of germplasm are made in this regard:

1. Bulk imports of planting materials should be discouraged as far as possible because the pest/pathogen introduction risk increases in proportion to the quantity of material. It is so because thorough examination and treatment of bulk consignments is difficult and the area under cultivation becomes too large for effective monitoring of the crops. If it becomes absolutely essential to import propagating material in bulk, it should be imported from seed companies/agencies reputed to produce seed/planting material under strict phytosanitary conditions.

2. Bulk imports for consumption should be de-vitalized making them unfit for planting and these should be processed immediately on arrival under supervision of quarantine officials.

3. All imports, whether for consumption or planting for commercial or for research purposes, should be done under 'Import Permit' only, and all conditions mentioned in the permit should be strictly followed.

4. All the plant material being brought by passengers coming to India must be handed over to the plant quarantine officials for inspection at the international airports/seaports, where separate 'Plant Quarantine Counters' should be established urgently.

5. At the international post-offices, all the mail should be passed through some kind of detection or scanning system as is done at the time of security check, and intercepted plant materials should be passed on to the plant quarantine officials for inspection. In fact, a plant quarantine official should be posted at each of the international post-offices to coordinate the interception of planting materials and their despatch to plant quarantine service for inspection before release.

6. In case of germplasm, repeat introductions should be avoided as the pest risk increases with repeat introduction of germplasm material into the country. The National Bureau of Plant Genetic Resources, New Delhi, has been designated by the government as the national nodal agency for exchange of germplasm for research purposes. All requests for germplasm should be routed through this Bureau alone. This would help in avoiding repeat introduction and materials could be made available to the users much faster and with required quarantine safeguards.

7. Domestic quarantine is as important as the international quarantine and, therefore, planting material should be moved from one state to another or from one place within a state to another under strict phytosanitary conditions.

8. Effective linkages/cooperation should be established among various organisations/agencies involved in the import of plant material for effective plant quarantine implementation and smooth flow of material.

9. Periodic workshops/meetings at national level involving concerned departments may be held to discuss common problems and impediments so as to help the national crop improvement programme.

Summary

Various plant pests and pathogens inflict heavy crop losses both under field as well as under storage conditions. Plant quarantine regulations promulgated by governments of different countries are designed to regulate the introduction and movement of plants, planting materials, plant products, etc. with a view to prevent the introduction of associated pests, pathogens and weeds exotic to a country or a region and which are harmful to its agriculture. Plant quarantine is effective only against such pests which have no natural means of transport. Plant quarantine as a national service and its complementary role have been briefly discussed. Techniques for the detection of pests and pathogens, and salvaging of infested/infected material have been described. Plant quarantine regulations with particular reference to India and the quarantine responsibilities of NBPGR in respect to the introduction of germplasm material for research use in the country have been discussed. Importance of national level coordination and national and regional cooperation in smooth flow of seed/planting material with effective plant quarantine safeguards have also been discussed. In the end, some suggestions have been made for strengthening the plant quarantine system and for its effective implementation in the country so that the much needed germplasm and other planting materials could flow in smoothly with required safeguards.

References

Anonymous. 1975. The Destructive Insects and Pests Act, 1914 and the rules made thereunder by the Central Government from time to time. Directorate of Plant Protection, Quarantine & Storage, Ministry of Agriculture & Irrigation, Department of Agriculture, Government of India.

Anonymous. 1985. The Plants, Fruits and Seeds (Regulation of Import into India) Order, 1984. Ministry of Agriculture & Cooperation, Department of Agriculture, Government of India.

Anonymous. 1988. New policy on seed development. Ministry of Agriculture, Department of Agriculture and Cooperation, Government of India.

Anonymous. 1989. The Plants, Fruits and Seeds (Regulation of Import into India) Order, 1989. Ministry of Agriculture, Department of Agriculture and Cooperation, Government of India.

Kahn, R.P. 1977. Plant quarantine: Principles, methodology and suggested approaches, pp. 289-308. In-Plant health and quarantine in international transfer of plant genetic resources (Eds., W.B. Hewitt and L. Chiarappa). CRC Press, Cleveland, USA.

Kahn, R.P. 1979. Tissue culture application in plant quarantine, pp. 185-201. In Practical tissue culture applications (Eds., R. Maramorsch and H. Hirumi). Academic Press, New York, USA.

Lambat, A.K., M.R. Siddiqui, Ram Nath, A. Majumdar and I. Rani. 1974. Seed-borne fungi of sugarbeet in India with special reference to Phoma betae Frank and its control. Seed Research. 2: 33-40.

Mathys, G. 1975. Thoughts on quarantine problems. EPPO. Eur. Mediterr. Plant Prot. Organ. Bull. 5(2): 55.

Neergaard, P. 1977a. Seed pathology, p. 1187. Macmillan Press Ltd., London, UK.

Neergaard, P. 1977b. Methods for detection of seed-borne fungi and bacteria, pp. 33-38. In Plant health and quarantine in international transfer of genetic resources (Eds., W.B. Hewitt and L. Chiarappa). CRC Press, Cleveland, USA.

Neergaard, P. 1977c. Quarantine policy for seed in transfer of genetic resources, pp. 309-314. In Plant health and quarantine in international transfer of genetic resources (Eds., W.B. Hewitt and L. Chiarappa). CRC Press, Cleveland, USA.

Rao, Y.P. and J.C. Durgapal. 1966. Seed transmission of bacterial blight disease of Sesame (Sesamum orientale L.) and eradication of seed infection. Indian Phytopath. 19: 402-403.

Singh, R.B. 1987. Current status and future prospects of use of tissue culture in plant quarantine for exchange of germplasm and planting material - An Overview. Paper presented during 'FAO Expert consultation on use of tissue culture in plant quarantine for exchange of planting materials', New Delhi, India, 26 February - 2 March 1987. FAO, Bangkok.

Srivastava, D.N. and Y.P. Rao. 1963. Seed transmission and control of bacterial blight of guar (Cyamopsis tetragonoloba L. Taub.). Indian Phytopath. 16: 390-391.

Stakman, E.C. 1969. The need for intensified and integrated campaigns against pests and pathogens of economic plants. Rockefeller Foundation, 47 p (mimeographed), March 1969.

Appendix I. Important pathogens and pests intercepted on introduced seeds/planting materials at NBPGR*

Pathogens/pests

Crop species

Sources

Fungi



Alternaria brassicae

Brassica spp.

Italy, Sweden, Taiwan


Phaseolus vulgaris

USA


Spinacea oleracea

Netherlands

A. helianthi

Daucus carota

France, Poland, USA, UK


Lycopersicon esculentum

Taiwan

A. porri.

Allium sp.

Iran

A. solani

Hibiscus sp.

Nigeria

Ascochyta pisi

Pisum sativum

Czechoslovakia, Hungary,



USA

A. pinodes

Pisum sativum

UK

A. sojicola

Glycine max

USA

Botrytis allii

Allium spp.

France

B. cinerea

Aegilops spp.

Greece, East Germany, USA


Amaryllis sp.

USA


Brassica spp.

Sweden


Calligonum sp.

USSR


Carthamus tinctorius

Italy, USA


Cucumis sp.

USA


Ferula assafoetida

USSR


Ficus spp.

USA


Helianthus annuus

Italy, USA


Hordeum vulgare

Italy


Pisum sativum

West Germany


Rosa spp.

W. Germany, Netherlands, USA, UK


Triticum spp.

Italy


Vitis spp.

Belgium, Czechoslovakia, Switzerland, USA, USSR


Zea mays

USA

Botryodiplodia theobromae

Cinnamomum sp.

Sri Lanka

Claviceps purpurea

Aegilops spp.

East Germany


Agropyron spp.

East Germany, USA


Festuca sp.

USA


Hordeum vulgare

USA


Lolium sp.

Italy


Secale cereale

Canada, USA


Triticum spp.

Italy, USA

Colletotrichum acutatum

Lycopersicon esculentum

USA


Medicago spp.

Australia


Panicum maximum

Australia

C. falcatum

Saccharum spp.

USA

C. graminicola

Glycine max

Taiwan


Sorghum sp.

Nigeria


Vigna unguiculata



Zea mays

USA


Z. diploperennis

USA

C. lagenarium

Cucumis melo

USA

Diplodia maydis

Zea mays

Mexico

Drechslera avenae

Avena sativa

Australia


Agropyron sp.

USA


Hordeum vulgare

Germany, Italy


Triticum spp.

Hungary, USA, Italy

D. graminea

Aegilops sp.

East Germany


Hordeum vulgare

Italy, Sweden


Triticum sp.

Hungary, Italy, USSR

D. maydis

Capsicum spp.

USA


Corchorus sp.

UK


Echinochloa spp.

USA


Eleusine spp.

Malawi, Sweden, USA, UK, Zambia, Zimbabwe


Hordeum vulgare

Italy


Lycopersicon esculentum

Taiwan


Panicum miliaceum

Mexico


Pennisetum purpureum

Taiwan


Setaria spp.

UK, Mexico


Sorghum spp.

Nigeria, Philippines, USA


Stylosanthes sp.

Australia


Tripsacum sp.

USA


Zea mays

Argentina, China, Nigeria, Mexico, Pakistan, Thailand, USA

D. nodulosa

Eleusine spp.

Italy, Malawi, UK, Zambia, Zimbabwe

D. oryzae

Eleusine spp.

UK, Zambia, Zimbabwe


Oryza sativa

Netherlands, Philippines, USA

D. pluriseptata

Eleusine sp.

Zambia

D. sacchari

Echinochloa spp.

Japan


Eleusine sp.

Italy


Panicum maximum

Australia


P. miliaceum

Mexico


Triticum aestivum

Hungary

D. sorghicola

Eleusine spp.

Zambia


Panicum maximum

Australia


Melilotus alba

Taiwan, USSR


Momordica charantia

USA


Sorghum spp.

USA


Zea mays

Mexico

D. sorokiniana

Aegilops spp.

China, East Germany, USA


Agropyron spp.

USA


Atriplex sp.

Australia


Atropa belladona

Portugal


Avena sativa

USA, USSR


Beta vulgaris

Germany


Carthamus tinctorius

Italy, USA


Capsicum sp.

Philippines


Cucumis sp.

USA


Daucus carota

West Germany


Echinochloa spp.

Japan


Eleusine spp.

Italy, Japan, UK, Zambia, Zimbabwe


Fagopyrum sp.

USSR


Glycine max

Taiwan


Gossypium sp.

USSR


Hynaldia sp.

China


Helianthus annuus

USA


Hordeum spp.

Canada, Italy, Mexico, Sweden, Syria, USA, USSR


Luffa sp.

Philippines


Lycopersicon esculentum

Taiwan


Panicum miliaceum

Mexico


P. maximum

South Africa, Australia


Secale cereale

Canada


Setaria spp.

Mexico, UK, South Africa


Solanum melongena

Japan


Sorghum spp.

USA


Triticum spp.

Australia, Brazil, Canada, Italy, Israel, Norway, Korea, Sweden, UK, USA, USSR


Zea mays

USA, South Africa

D. teres

Aegilops spp.

USSR


Hordeum spp.

Canada, Italy, Syria, USSR


Triticale

Greece


Triticum spp.

Hungary, Italy, USA, USSR

Fusarium avenaceum

Cassia sp.

Australia


Daucus carota

Hungary


Glycine max

USA


Triticum spp.

Italy

F. culmorum

Acacia sp.

Australia


Aegilops spp.

East Germany


Agropyron spp.

USA


Glycine max

Taiwan


Hordeum spp.

Italy


Phaseolus sp.

USA


Vigna unguiculata

Nigeria, USA


Triticum spp.

Italy, Netherlands, USA, UK, USSR, Sweden

F. fusarioides

Cicer arietinum

USA


Glycine max

USA


Triticum spp.

Italy

F. graminearum

Hordeum spp.

Italy


Triticum spp.

Italy, USA, Netherlands


Zea mays

Mexico

F. nivale

Aegilops spp.

East Germany


Hordeum spp.

Italy


Triticum spp.

Hungary, Italy, Sweden, UK

F. oxysporum

Allium sp.

USA


Capsicum spp.

Romania


Cicer arietinum

USA


Leucaena spp.

USA

F. solani

Abutilon sp.

USA


Acacia sp.

Australia


Aegilops spp.

East Germany, USA


Agave sp.

USA


Allium sp.

East Germany


Beta vulgaris

Hungary, Poland, USA


Brassica spp.

Taiwan


Capsicum spp.

Italy, Romania, USA, USSR


Carica papaya

Australia, Venezuela


Carthamus tinctorius

East Germany, Turkey, USA


Casuarina spp.

Australia


Centrosema spp.

Australia


Cicer arietinum

USA


Crotalaria juncea

USA


Digitalis viridiflora

Italy


Eleusine spp.

UK, Zambia, Zimbabwe


Glycine max

Poland, USA, Taiwan


Grossularia sp.

USSR


Guizotia abyssinica

Australia


Helianthus annuus

East Germany


Hibiscus spp.

Brazil, UK


Hordeum spp.

Italy


Ipomoea batatas

USA, Taiwan


Lens culinaris

Syria


Lesquerella spp.

USA


Limnanthes alba

USA


Lycopersicon esculentum

Taiwan


Manihot sp.

Brazil


Medicago spp.

Hungary, USA


Melilotus alba

Taiwan, USSR


Panicum spp.

USSR


Phaseolus aconitifolius

USA, Taiwan


Pisum sativum

USA


Plantago maritima

USSR


Prunus spp.

Turkey


Rosa spp.

Netherlands


Spinacea oleracea

USSR


Solarium melongena

USA, Japan


S. tuberosum

Peru


Sorghum spp.

USA


Stylosanthes spp.

Australia, USA


Trifolium spp.

Australia, USA


Triticum spp.

Italy, Sweden, USA


Vigna unguiculata

Brazil, Italy, Nigeria, Taiwan


Vitis spp.

South Africa


Zea mays

South Africa

Gloeocercospora sorghii

Sorghum vulgare

Nigeria, Philippines

Melanconium sacchari

Saccharum spp.

USA

Neovossia indica

Triticum aestivum

Mexico, Syria, Sweden, Turkey

Peronospora manshurica

Glycine max

Brazil, Malaysia, Korea, Poland, Taiwan, USA

Phoma betae

Beta vulgaris

Belgium, Germany, Hungary, Italy, Japan, Poland, Romania, Sweden, UK, USSR

P. lingam

Brassica spp.

UK

Phomopsis sojae

Glycine max

Poland, Taiwan, USA

Puccinia carthami

Carthamus tinctorius

Australia, Greece, Italy, Turkey, USA

Tilletia barclayana

Oryza sativa

Philippines

T. caries

Triticum spp.

Afghanistan, Egypt, Italy, Netherlands, Mexico, Turkey, USA

T. foetida

Triticum spp.

Hungary, Syria, USA

Tolyposporium penicillariae

Pennisetum sp.

UK

Uromyces betae

Beta vulgaris

Italy, UK, USA

Ustilago maydis

Zea mays

USA

Verticillium albo-atrum

Allium sp.

East Germany

Nematodes



Anguina sp.

Stylosanthes (seeds)

Australia

A. tritici

Triticum aestivum

Turkey, UK, Italy

Aphelenchoides besseyi

Digitaria smutsii, Oryza sativa, Oryza glaberrima, Guilielma gasipee

Philippines, USA, Brazil, Madagascar, Burma, UK, Indonesia, Australia, Costa Rica

A. composticola

Orchids

Australia

A. fragariae

Strawberry plants (soil), Dahlia sp. (soil), Orchid seedlings, Fragaria sp. (plants)

USA, Netherlands, Australia

Ditylenchus angustus

Oryza sativa

Madagascar

D. destructor

Humulus lupulus (rooted cuttings), Solarium tuberosum (tubers)

Australia, W. Germany, Peru

D. dipsaci

Alfalfa (Medicago sativa) seeds, Flower bulbs, Hops (rooted cuttings), Hyacinthus sp., Tulipa sp., Narcissus sp.

USA, Netherlands

Heterodera goettingiana

Pisum sativum (soil clods)

UK

H. humuli

Humulus lupulus (rooted cuttings)

Australia, W. Germany

H. schachtii

Beta vulgaris (soil clods)

W. Germany, Denmark, Italy

Meloidogyne hapla

Rosa sp.

W. Germany

M. incognita

Glycine max (debris)

USA

M. javanica

Jade plants, Pistacia vera (rooted seedlings)

Philippines

Pratylenchus hamatus

Mentha spicata (rooted material)

Brazil

P. brachyurus

Fragaria sp. (plants)

USA

P. crenatus

Malus sp., Rosa canina (rooted plants)

UK

P. penetrans

Rubus sp. (rooted cuttings), Cynodon dactylon, Mentha piperita (rooted cuttings)

USA, Bulgaria

P. vulnus

Prunus taihaka (plants), Annona sp. (rooted plants), Fragaria sp., Musa sp., Pyracantha sp.

UK, Australia, Italy, Canada, Surinam, USA

Tylenchorhynchus dubius

Malus lancifolia (plants)

UK

T. neoclavicaudatus n. sp.

Solanum tuberosum (soil)

Peru

Insects



Acanthoscelides obtectus

Cajanus cajan, Phaseolus vulgaris, Vigna sp.

Brazil, Colombia, Italy, Nigeria, USA

Anthonomus grandis

Gossypium sp., Hibiscus sp., Sesamum sp., Vigna unguiculata

USA Italy, Zambia

A. fasciculatus

Allium sp., Cajanus cajan, Leucaena diversifolia, L. leucocephala, Psophocarpus sp., Vigna radiata, Zingiber officinale

Fiji, Indonesia, Italy, Philippines, Thailand, USA

Bruchidius atrolineatus

Vigna radiata, V. unguiculata

Italy, Nigeria, UK

B. glycyrrhizae

Glycyrrhiza glabra

Iran

B. halodendri

Glycyrrhiza glabra

Iran

Bruchophagus gibba

Medicago sp.

USA

B. glycyrrhizae

Glycyrrhiza sp., G. glabra

Iran, Iraq, USSR

Bruchus lentis

Lens culinaris, Vigna mungo

Syria, Taiwan, USA, USSR

B. pisorum

Cajanus cajan, Lathyrus sativus, Pisum sp., Phaseolus vulgaris, Vicia faba, Vigna radiata

Hungary, Italy, Nepal, Syria, Turkey, USA, USSR

Callosobruchus analis

Lens sp., Vigna umbellata

Indonesia, Syria

C. chinensis

Atylosia sp., Cajanus cajan, Phaseolus mungo, Vigna sp., V. unguiculata

Australia, Japan, Indonesia, Italy, Nigeria, Philippines, Taiwan, USA

C. maculatus

Cajanus cajan, Cassia sp., Lablab purpureus, Vigna mungo, Vigna sp., Vigna radiata, V. umbellata

Australia, Japan, Indonesia, Italy, Nigeria, Philippines, Taiwan, USA

C. phaseoli

Lablab purpureus

Australia

C. subinnotatus

Voandzeia sp.

Nigeria

Carpophilus freemani

Zea mays

Philippines

Carpocapsa pomonella

Juglans regia

USSR

Cheyletus eruditus

Olea sp.

USSR

Ephestia cautella

Gmelina arborea

Thailand

E. elutella

Macadamia (nuts), Vigna sp.

USA

Ericoccus araucaria

Araucaria angustifolia (plants)

Argentina

Exeristes roborator

Gossypium sp.

Syria

Horismenus depressus

Acacia sp.

USA

Hypothenemus bauhinae

Abelmoschus esculentus

Nigeria

Lasioderma serricorne

Coix lacryma-jobi, Cucurbita sp., Gossypium sp., Matricaria chamomilla, Ricinus communis

Brazil, Hungary, USA, Zambia

Lixus albomarginatus

Beta vulgaris

Italy

Mimosestes amicus

Cercidium sp.

USA

Mycetophagus quadriguttatus

Cocos nucifera

Ivory Coast

Orzyaephilus mercator

Arachis hypogaea, Bauhinia sp., Zea mays

Philippines, Thailand, USA

O. surinamensis

Beta vulgaris, Triticum spp.

Italy, Mexico

Oxycarenus hyalinipennis

Abelmoschus esculentus

Nigeria

Oscinella frit

Hordeum vulgare

Sweden

Procellio scaber

Cassia sp. (plants)

Hawaii

Ptinus exularis

Eucalyptus obliqua

Australia

Rhizopertha dominica

Allium sativum, Beta vulgaris, Hordeum vulgare, Oryza sativa, Vigna sp., Triticale, Zea mays

E. Germany, Egypt, Italy, Mexico, Philippines, Sweden, Thailand, Syria, UK, USA

Sitophilus granarius

Avena sativa, Triticale, Triticum sp.

France, Hungary, Mexico, Turkey, UK, USA, Upper Volta

S. oryzae

Hordeum vulgare, Carya ovata, Myricaria cauliflora, Oryza sativa, Sorghum sp., Triticale, Triticum sp., Zea mays

Brazil, Egypt, Kenya, Mexico, Philippines, Sweden, Thailand, UK, USA

Sitotroga cerealella

Oryza sativa Zea mays, Triticale

Nigeria Philippines

Spermophagus pygopubens

Hibiscus sp.

UK, USA

Specularius erythreus

Cajanus cajan, Vigna radiata

Italy

Stator pruininus

Leucaena leucocephala

USA

S. limbatus

Acacia sp.

USA

Torymus druparum

Pyrus communis

Romania

Tribolium castaneum

Beta vulgaris, Gladiolus sp., Hordeum vulgare, Simmondsia chinensis, Vigna sp., Triticum spp., Zea mays

China, Germany, Italy, Mexico, Pakistan, Philippines, Poland, Romania, Sweden, Syria, Thailand, UK, USA.

Trogoderma granarium

Atropa belladona, Beta vulgaris, Carthamus tinctorius, Hordeum vulgare, Triticum spp.

Afghanistan, France, Iran, Israel, Germany

T. inclusum

Beta vulgaris

Italy

Typhaea stercorea

Cocos nucifera

Ivory Coast

Tyrophagus longnor

Vitis sp. (cuttings)

USA

Zabrotes subfasciatus

Phaseolus sp., P. vulgaris

Colombia

* Adopted from 'Research achievements - A decade' Scientific Monograph No. 11, 1987, National Bureau of Plant Genetic Resources, New Delhi-110 012 (Eds., K. P. S. Chandel and B. M. Singh).


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