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M. Emel Okten

Nematology in Turkey
Nematological problems
Control measures
Infrastructure and training
Support for nematology
Conclusions and recommendations


Turkey is an agricultural country and has a considerable amount of agricultural production potential in terms of soil, climate and water resources. Forest land occupies about 42 percent of the country, and 40 percent of agricultural land is occupied by field crops, fruit-trees and vegetable crops. Among the field crops, cereals are followed by pulses, oilseeds and tuber crops. The areas sown and production of crops are given in Tables 26 to 30.

The Southeast Anatolia Project (GAP) will give rise to great changes concerning the areas sown and production levels.

Nematology in Turkey

Nematological studies in Turkey started in the 1930s at almost the same time as other plant protection sciences such as entomology, phytopathology, etc. Nematology had for long been considered part of entomology and entomologists were involved in nematological studies. Until recent years, plant-parasitic nematodes have attracted less attention than insects, viruses, bacteria and fungi. Nematology has made little progress because of the inaccessibility of nematodes in soil and plant roots and their microscopic size. There have been technological difficulties in their examination, because the symptoms that they produce are easily mistaken for those of other factors. In Turkey, the importance of nematology was realized very late and certain independent laboratories were established as affiliates of the agricultural control institutes. Having operated independently before, these laboratories are now considered part of entomology branches, which seems to affect working conditions adversely to some extent. The number of qualified personnel is also decreasing because of retirement and vacant posts not being filled.

Cultivated area and production of field crops


Sown (ha)

Production (tonnes)


13 740 895

23 366 600


2 310 261

1 676 592

Industrial crops

1 449 812

11 864381


966 334

2 494 883

Tuber crops


5 543 000


18 744 402

44 945 456

Fruit-trees and production

Number of fruit-trees

Production (tonnes)

Soft fruit

46 259 000

2 369 000

Stone fruit

116 434 000

1 680 000


20 847 000

1 443 000


286 649 000

822 000


14 796 000

3 940 000


484 985 000

10 254 000

Fodder crops


Area sown
(ha × 10s)

Area harvested
(ha × 10s)



Silage maize



(tonnes × 103)








Cow vetches







Wild vetches












1 704










1 070

1 055



2 221

1 571

Tea plantation area and production of green leaves

Number of tea growers

Area of tea plantation (ha)

Production of green leaves (tonnes)

202 082

89 525

662 549

Area sown and production of vegetables

Area (ha)

Production (tonnes)

Total area


Leafy or stem vegetables

1 287 740

Leguminous vegetables


Fruit-bearing vegetables


Root, bulb and tuberous vegetables

433 080

Other vegetables


Total production

15 282 830

Contacts with experts in relevant fields in other countries are not as satisfactory as might be expected for an awareness of technological developments and exchange of information.

Since Turkey is an agriculture-oriented country, nematological studies have primarily concentrated on parasitic nematodes that bring about damage to agricultural products. In the recent past, taxonomic studies, which are the basic research subject, have been highlighted. In addition, studies are planned to use biological control agents and put them into practice.

Nematological problems

Turkey comprises seven geographical regions where a variety of products are grown, ranging from citrus, banana, hazelnut, tea, cereals, to all kinds of vegetables and fodder as well as industrial and ornamental plants and forest products.

The following are some important plant-parasitic nematodes:

· root-knot nematodes (Meloidogyne spp.) on fruits, vegetables, ornamental plants, industrial crops;

· stem and bulb nematode (Ditylenchus dipsaci) on onion, garlic, fodder plants, strawberry and ornamental plants;

· seed-gall nematode (Anguina tritici) found in some locations in wheat fields (under control);

· cyst nematode (Heterodera schachtii) found in some locations in sugar-beet plantations (under control);

· foliar nematode (Aphelenchoides fragariae) on strawberries;

· spiral nematode (Helicotylenchus multicinctus) on banana;

· citrus nematode (Tylenchulus semipenetrans) on citrus;

· dagger nematodes (Xiphinema spp.) in vineyards.

Economic losses: root-knot nematode has been found to cause 25 to 35 percent damage on tomato and eggplant.

The areas in which economically harmful nematodes are present are generally where their host plants are grown and where the climatic and soil conditions are conducive. Root-knot nematodes become a problem in vegetable greenhouses in the south of the country and stem and bulb nematodes have been observed in some onion-growing regions. Information is provided to farmers in these regions by experts from the Ministry of Agriculture about the control measures to prevent spread of infection to clean areas from those already infected. The effects of crop damage caused by nematodes are significant for some crops but not for others in terms of their yield losses. However, the main problem is to control the nematodes in the infected areas and prevent other clean areas becoming infected.

Control measures

Since chemical control is not practical, it is necessary to adopt cultural measures for nematode control. As mentioned above, certain measures for internal quarantine need to be implemented. External quarantine measures are always regarded by experts as important and there is awareness that new harmful agents might infiltrate into the country thus infecting export products with nematodes subject to quarantine.

Since chemical control is recommended mostly as treatments applied to soil prior to planting, fanners avoid adopting such applications because of the exorbitant expenses involved. It is mainly because of the resulting environmental effects that pesticide measures are avoided as much as possible, as is the case with the control of insects and diseases. Hence, cultural measures such as avoiding the use of infected production material and sowing in rotation are of greater priority.

Other studies are also being conducted on native species that are adapted to some regions. There are no particular studies on the biological control of plant-parasitic nematodes at present, but some are planned on the determination and potential of certain insect-parasitic nematodes as biological control agents.

European Union regulations for internal and external quarantine have been adopted and updated in line with the country's conditions. On a nationwide basis, integrated controls have been adopted as an agricultural control strategy, and it is within this framework that studies are being carried out. Control of nematodes is also included in this strategy.

Infrastructure and training

The number of researchers and teachers is too small and quality is inadequate; there are few young nematologists. Research and training studies are today carried out by the relevant departments of universities and research establishments of the Ministry of Agriculture. The latter mainly aim to do applied research. There are four agricultural control research institutes which perform nematological activities in various regions. The existing technology supports these studies but no appropriate laboratories have been established yet with the capacity to meet recent progress in techniques.

Technical personnel in applied institutions and farmers are trained by teachers from research organizations either directly or indirectly. Doctorate and master's studies for expert staff at research organizations are led by universities. Training opportunities are very limited and financial constraints hamper participation in meetings, short-term courses and conferences held outside the country.

Factors that restrict progress are summarized below:

· difficulties experienced in obtaining literature and lack of communication prevent researchers from following work carried out abroad;

· inadequacy of personnel, equipment and other facilities;

· other obstacles such as financing large-scale projects. Projects that are implemented at research institutions are generally financed by the Ministry of Agriculture. Support is also available from the Turkish Scientific and Technical Research Agency (TUBITAK), the State Department of Planning (DPT) or the Atomic Energy Institution, or cooperation is set up with other research organizations for this purpose. There is no existing project in the field of nematology that is supported by foreign aid programmes. For agricultural research studies, nematologists are also appointed as teachers at the foreign-financed Agricultural Extension and Applied Research Project (TYUAP).

Support for nematology

Although some financing institutions are mentioned above, their financial support is far from meeting the demand.

Conclusions and recommendations

If financial support could be obtained, existing infrastructure and personnel could become involved in close cooperation with nematologists in other countries and thus open the way for further research. Taking into consideration Turkey's quite rich fauna and flora, projects in the field of biological control can be carried out jointly since they are especially relevant today.


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