Seed-borne Pathogens on Wheat (Particularly Smuts) in Turkey1

The important seed-borne diseases of wheat in Turkey are common bunt ( Tilletia caries and T. foetida ), loose smut ( Ustilago nuda tritici ), dwarf bunt ( T. contraversa ) and flag smut ( Urocystis tritici ). Seed treatment against common bunt is widely used in Turkey. The damage is about 10–15 %, sometimes 90 % in some fields where seeds are sown without treatment. About 10 % of wheat fields were infected with bunt during 1972–1974. Seed treatment with carboxin (Vitavax) is recommended against loose smut of wheat in Turkey, but has not yet been used. Some wheat varieties, especially Siirak (1593/51) wheat, are highly susceptible to loose smut. The proportion of smut-infected heads reached 30–40 % in this variety and about 32 % of wheat fields were infected with loose smut during 1972–1974. The damage was about 6 % in infected fields. Yield losses were at least 35,000 tons. Dwarf bunt is distributed at high altitude (1300–2000 m) in eastern Turkey; 2500 ha of wheat fields are infected with dwarf bunt. The disease causes 1–80 % losses in some fields. The wheat variety Yayla 305 is recommended for infected areas. Flag smut is present in some areas of Turkey, but yield losses are not important. Seed treatment is effective against seed-borne spores.     

Maize Pests and their Importance in Turkey1

Maize and related crops suffer from a large number of insect pests in Turkey but all are not of the same importance in different parts of the country. This paper lists about 80 species, of which only a few ( Sesamia nonagrioides, Helicoverpa armigera, Ostrinia nubilalis , cutworms ( Agrotis spp.), Tanymecus dilaticollis, Gryllotalpa gryllotalpa ) are of primary importance. The pest status and distribution of each species is described.     

Noctuid Species Causing Damage to Maize in Turkey1

In Turkey, maize is grown in the Black Sea, Marmara and Aegean Regions as well as in the southern part of the country, with a total area of 600,000 ha. Control measures againsts pests play an important part in maize production. Noctuid species are important maize pests in Turkey, and the following species occur: Scotia ipsilon, Scotia segetum, Sesamia nonagrioides, Sesamia cretica, Mythimna loreyi, Mythimna unipuncta, Spodoptera exigua. Research on the ecology of S. ipsilon is being conducted in the Black Sea Region. This species passes through 4 to 5 generations annually. In recent years, S. nonagrioides has been found in the Aegean Region and studies on this pest have started. S. cretica is widely distributed in the Marmara, Mediterranean and South-eastern Regions of Turkey. This species produces two generations annually. M. loreyi and M. unipuncta cause damage only in limited areas. Helicoverpa armigera and S. exigua are widely distributed throughout the maize-growing regions, but cause considerable damage only in limited areas.     

Studies on the Pathogenic Races of Tilletia foetida and Tilletia caries and their Pathogenicity on Some Wheat Varieties in Turkey1

Twenty-nine pathogenic races of Tilletia foetida and eight of T. caries were identified during a survey of bunt races in Turkey in 1960–1971; 244 bunted heads and eight differential wheat varieties were used in these experiments. The pathogenicity of the 21 most extensive races was checked in 1970–1971. Some of them were stable in their pathogenicity, and some were not. In further race studies carried out since 1974, using more bunt material, 11 differential wheat varieties and the new classification method, 35 T. foetida and eight T. caries races were identified. Obviously, the number of races will increase as the studies continue. The 21 most extensive races identified in the primary studies were tested on 16 wheat varieties cultivated in Turkey. All races used were virulent on nine varieties and avirulent on two varieties. Virulence on the other five varieties was variable.     

New Trends in the Chemical Control of Wheat Diseases1

Following a list of the economically most important fungal wheat diseases, recent trends in chemical seed treatment are discussed. Different fungicide mixtures are now available for the replacement of mercurial dressings, but are generally more expensive. The control of fungal diseases by spraying has become more and more common over the past ten years in certain countries. Advantage has been taken of the curative action of the modern systemic chemicals. The major diseases are powdery mildew, rusts, eyespot, glume-and leaf-blotch. The general application of a fungicide programme is restricted by regional wheat prices, and should also be limited to reduce environmental contamination. Knowledge about economic thresholds and correct timing of control are indispensable, and in special cases the development of warning systems is advisable. The role of Cycocel (chlormequat) is also discussed. A danger of fungicide resistance in populations of plant pathogenic fungi has arisen with the introduction of the systemic fungicides (one-site-inhibitors). As yet, however, no economically important case of fungicide resistance within cereal pathogens is known. Factors favouring the stepwise selection of resistant strains under field conditions are discussed in detail, and experimental data are presented on this subject. Other positive or negative side-effects of the modern fungicides are described.     

Mycological Diagnostic Problems1

In diagnostics we are constantly confronted with the gaps that exist in our knowledge of the pathogenic fungal flora. This situation is illustrated by recent information concerning various economically important fungal diseases. Where such problems arise it is only through international cooperation in diagnostic mycology that they can be efficiently tackled and solved. It appears that with increasing frequency the exact identification and differentiation of fungi is only made possible through familiarity with their growth characteristics in culture. Fungus culture collections can here play an important role, since exact comparison and identification is made possible. Such pathogenic fungi should be made available for diagnostic purposes under the auspices of the Plant Protection Services, so that the risk of unwanted spreading of these pathogens can be avoided. The Plant Protection Services would in fact become more effective in their attempts to prevent and limit the distribution of harmful organisms.     

Fireblight monitoring in Lithuania1

Lithuania has requested that its whole territory should be recognized by the EU as a protected zone for Erwinia amylovora . Fireblight monitoring was performed in 1998/2002 with the aim of detecting and identifying the bacterium, and of determining its distribution in the country. The study consisted of periodic surveys (at least twice a year) of nurseries, orchards, collective farms and host plants, growing individually or in small groups, as well as the surrounding zone within a radius of 250 m. Tests, under conditions of quality control, were applied to host plants with and without symptoms, using detection methods such as ELISA and immunofluorescence (with polyclonal antibodies), semi-selective plating and pathogenicity.     

High Performance Self-Propelled Sprayers1

Self-propelled sprayers, which are the result of recent technological advances in farm machinery for crop protection, combine the advantages of ground equipment and airborne spraying appliances: a work rate of 100 ha per day can be achieved under comfortable working conditions, their ease of handling makes it possible to work at short notice and at almost any time of the year. Labour costs are reduced, and effective treatment can be guaranteed. This is the main economic justification of the use of these machines which, in view of their relatively high purchase cost, are suitable for farms of at least 300-400 ha.     

New Techniques in Seed Treatments1

The paper deals with the treatment of seeds other than cereals and describes the technique of seed coating with the incorporation of the required pesticides. The formulation of the pesticides has to be modified for this technique. The advantages of seed coating are given and include the increased loading of chemicals onto seeds, thereby increasing the diseases and pests that can be controlled by the coating technique.     

International Cooperation in Plant Protection1

Preventing the introduction of dangerous organisms into new countries and regions requires an international approach. The article reviews the most dangerous organisms for different continents, and describes in particular the procedures developed in Europe for assessing quarantine risks, through international cooperation within the European and Mediterranean Plant Protection Organization. The activities of EPPO are reviewed, and also those of the ISHS Plant Protection Commission, especially in relation to fruit-tree viruses. The implementation of international cooperation within the European Community, and specifically in Denmark, is described.     

Droplet Formation and Deposition1

At the EPPO Conference in Belgrade on 1970 the author reported on work showing that small, uniform, and non-volatile droplets appeared to offer the prospect for greatly reduced dosages of pesticides by both providing a more effective deposit and by controlling drift. Three recent studies provide further evidence for this hypothesis, which questions the very principles on which our present spraying practices are based. However, the deposition of droplets by the external forces of wind and gravity imposes lower limits on the droplet sizes capable of being used. These are 30 μm for insecticides and fungicides (except in the case of flying insects) and 150 μm for herbicides, since the droplets require sufficient energy to impact themselves on the target. Electrostatic charging of droplets promises to free us from these size constraints by providing the droplet with a depositional force of its own, allowing it to impact on any surface. Electrostatics, however, is solely a force of deposition and thus must be balanced with the forces required for spray dispersion so that the droplets can penetrate the crop canopy and/or be transported to the target     

Plant Quarantine Facilities in The Netherlands1

In The Netherlands germplasm and plants collected in the wild for breeding and scientific purposes may only be imported with a special licence. For this material specific post-entry import requirements are prescribed. A glasshouse with special quarantine facilities has been built on the premises of the Plant Protection Service at Wageningen. In this paper the special facilities needed to carry out post-entry quarantine are described.     

Possibilities of Microwaves in Soil Disinfestation1

In the search for alternative methods for soil disinfestation, various soil types (sand-loam, loam, clay-loam) with mycelium of Rhizoctonia solani, Fusartum oxysporum f. sp. lycopersici and Trichoderma longibrachiatum and seeds of Lepidium sativum , all present at various depths, were treated with microwaves (2540 MHz, 600 W). High lethality was found to be dependent on the duration of irradiation. The granulometric composition of the soil had a relatively strong effect on killing rate. The reaction to soil moisture content was remarkable, but quite reproducible: two maxima in killing rate could be established, one with extremely dry soil and the other with a relative soil moisture content of 60%. The effect of irradiation on CO₂ production and N-mineralization in the soil was also investigated.     

Analyzing Cost Effectiveness of EPIPRE1

EPIPRE is an integrated pest and disease management system for wheat, fully computerized, based on on-line calculations of costs and benefits of pesticide treatments; it is field-specific and utilizes disease and pest monitoring in the field. The development of the project took five years (1977/1981). Cost effectiveness has been estimated in retrospect and in prospect using 1980 as a base year, covering the period 1977 through 1985. Future costs were disccrunted at a 10 % rate. The Net Present Worth of the project was estimated at nearly eight million Dutch guilders. The nonmeasurable effects of the project seem to be even more important than the measurable effect.     

Electrostatic Application with Rotary Atomisers1

The APE80 charged rotary atomiser, and its larger, JUMBO, counterpart, both developed at Rothamsted, are briefly described. Recent design modifications allow control of the trajectory and subsequent distribution of the spray. Some field results illustrate the increase in deposition obtained with charged sprays and the effect on spray penetration.     

Prospects for Improving Pesticide Application in Hungary1

In Hungarian agriculture, large-scale farming is characteristic. The average size of State Farms exceeds 7000 ha, while that of the agricultural cooperatives approaches 4000 ha. In general, farms are well mechanized and agrochemical usage is also high. Per hectare of arable land in Hungary, the amount of pesticides applied annually is about 5 kg active ingredient. The application is carried out by 7000 large-scale ground equipments, 4000 machines for orchard and vineyard treatments, and 115 brigades for aerial application. The selection of both appropriate equipment and mode of application has an important role in achieving adequate biological efficacy at reasonable cost while ensuring energy saving and protection of the environment Now and in the future, great importance must be given to the following:a) widespread use of up-to-date equipment for pesticide application; b) nozzle selection in accordance with the purpose to be achieved; c) avoiding or impeding the total depreciation of machinery; d) regular control of the correct adjustment and the general state of equipment and establishment of an adequate servicing system; e) selection of equipment adapted to the pesticide formulation concerned; f) increased use of specific pesticide formulations; g) increased use of additives in order to control surface tension, droplet formation, drift etc.; h) establishment of a balance between use of ground and aerial equipment under given farm conditions; i) improvement of economical aerial application in plant protection; j) development of test methods and equipments to control the standards of application; k) examination of combinations of pesticides and other chemical (e.g. fertilizers).     

Grey Mould Damage and Control in Hungary1

Grey mould is one of the most important fungal diseases of grapevine, and for this reason the successful control of Botrytis cinerea determines the result of grape growing. As far as damage is concerned, the most important infection occurs at the end of flowering and just before ripening. The conidia of the fungus infect the berries through wounds, which may be caused by hail or storms, or by chewing insects, or also, most importantly, by physiological berry splitting. This occurs when a long dry period in summer is followed by a rainy autumn at ripening time. The prevention of wounds is one of the most important aspects of control. For the first half of the year, we propose using the traditional contact fungicides against grey mould. The use of benzimidazole-type systemic fungicides is proposed only for the last two treatments, because they have a low persistence and because in this way we avoid the development of resistance to these systemic fungicides.     

Integrated Control in the Netherlands 1)

In the Netherlands the need for an ecological approach in pest control has led to the establishment in 1958 of the Research Group on harmonious control of arthropod pests later renamed into Research Group on integrated control of arthropod pests which has several sections. This Group is part of the National Council for Agricultural Research of the Organization for Applied Scientific Research (TNO). There is a close co-operation between many Research Institutes towards developing integrated control of which the TNO Research Group is the co-ordinating body. The research priorities have been clearly defined and the ways leading to a practical implementation of integrated control studied.     

Evaluation of Novel Pesticide Application Techniques1

Most new pesticides are assessed in the laboratory and field assuming commercial application in sprays diluted to around 2001/na or more. Relatively few products are registered for ULV/CDA (ultra-low volume/controlled droplet application) sprays. Methodology for comparative assessment of novel application techniques is considered.     

Economic Aspects of Pest Control1)

The activities of economists associated with the IBP project entitled « The Principles, Strategies, and Tactics of Pest Population Regulation and Control in Major Crop Ecosystems » and their interaction with entomologists in the design and implementation of integrated control strategies are described. Profit maximization criteria and a method of considering farmers behaviour with respect to risk are developed. The term «economic threshold » is further clarified; and a simpler concept, « the damage threshold », is introduced. Regional institutions such as pest management co-operatives and districts and the factors which affect their introduction and successful operation are considered.