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During 1996-2000 the secondary succession on a field left fallow was investigated. The experimental area was divided into a ploughed and an unploughed part. Both parts were divided into 5 × 5 m plots that were either left intact (control), mowed in June or July, or superficially cultivated in June. The position of the plots was identical each year. In successive years total dry matter production decreased in all experimental plots; in unploughed plots more than in ploughed ones. The spread of Cirsium arvense (L.) Scop. was increased by ploughing and superficial cultivation. Ploughing stimulated the spread of perennial dicotyledonous plants more than mowing in June and July. Superficial cultivation increased the spread of perennial dicotyledonous plants in the first years. Later on the proportion of perennial dicotyledonous plants decreased and after 5 years the plots were dominated by Anisantha sterilis (L.) Nevski. The incidence of Elytrigia repens (L.) Desv. was highest in the 5th year on unploughed control plots. The spread of perennial monocotyledonous plants was lowest in ploughed and superficially cultivated plots.

ocids are commonly found to be a persistent pest in structures of grain stores. Grain residues are potential pest reservoirs that serve as sources of grain re-infestation. Weight losses caused by psocids on broken wheat kernels were measured. Average weight loss of grain samples was 9.7% after 3 months of Liposcelis bostrychophila infestation. The weight losses were positively correlated with progeny production.

Results of researches carried out in 2000 and 2001 have demonstrated, that main factors determining yield of winterwheat are: agrotechnical measures, mainly proper choice of field, optimal nitrogen fertilization as well as choice ofcultivar well adapted to local climatic conditions. Chemical protection of winter wheat affects first of all stability ofyield. Regular inspections of fields with special account to present phytosanitary situation, thresholds of noxiousness andexpected development of disease and pest populations should decide on the need of chemical treatments.

The tolerance to or phytotoxicity of selected herbicides and their impact on seed yield was investigated in six grasses grown for seed: Phleum pratense cv. Sobol (a), Festuca rubra cv. Táborská (b), Festuca pratensis cv. Otava (c), Poa pratensis cv. Slezanka (d), Arrhenatherum elatius cv. Medián (e) and Dactylis glomerata cv. Zora (f). All species were tolerant to Grodyl 75 WG (amidosulfuron 75%), (a) and (f) were tolerant to Grodyl plus (amidosulfuron 15 g/kg + isoproturon 600 g/kg) which was phytotoxic to the other grass species; all species were tolerant to Stomp 330 E (pendimethalin 330 g/l); Lintur 70 WG (triasulfuron 4.1% + dicamba 65.9%) was phytotoxic only to (c) while the other species were tolerant to it.

First outbreaks of fire blight were detected in Austria in 1993 and in Hungary in 1995. 137 Erwinia amylovora isolates were compared by PCR-RFLP, sequencing of the repeat region of the PstI fragment of plasmid pEA29, RAPD and AFLP analysis. Differences of repeat numbers in first isolates were observed. Six isolates showed different RAPD profiles. In AFLP analysis, so far, no differences in fragment pattern were determined. Pathogenicity tests with micropropagated apple cultivars revealed differences in plant susceptibility and in virulence of isolates. Responses of Malus tissue were visualized by the use of epifluorescence microscopy through the localization and the production of substances involved in cellular defence mechanisms (e.g. flavonoids, lignin) in various susceptible cultivars. The effect of bacterial strains differing in pathogenicity is shown by cellular peroxidase and flavonoid production.

Leaf spot pathogen is characterized as a highly developed parasite after investigation of development peculiarities of the fungus in pure culture and natural conditions. The degree of correlation depended on the medium. Impact of incubation temperature on Blumeriella jaapii (Rehm) Arx growth was different. Fungi colonies formed more intensively and their diameter increased significantly under higher temperature. Optimal conditions for the disease prevalence are 15-20°C and moisture. Relative humidity and precipitation influenced maturation of ascomycetes and discharge of ascospores (r = +0.89). Microscopic analysis of leaves showed that during winter thaw, when the average temperature is about 0 ± 5°C and relative humidity is higher than 70%, was possible to detect mature ascomycetes and conidia. It is possible to affirm that lower temperature than it was assumed is sufficient for formation of ascomycetes.

The effectiveness of fenarimol and difeconazole, DMIs fungicides, and dodine was tested in two experimental orchards and in greenhouse in two seasons. In 2001 monitoring of resistance to dodine was conducted also in some commercial orchards located in main apple production. In both experimental orchards fenarimol gave significantly poorer control of apple scab than difenoconazole when curative treatments were applied. The same results were obtained in greenhouse tests using for inoculation the suspension of conidia of V. inaequalis from these orchards. In many monitored orchards, in each region, a high level of dodine resistant isolates in population of V. inaequalis (even more than 40%) was noted. Only in six from 65 tested orchards there was less than 1% resistant isolates in population of the fungus.

To search for host proteins involved in systemic spreading of Tomato spotted wilt virus (TSWV), the virus-encoded NSm movement protein has been utilized as a bait in yeast two-hybrid interaction trap assays. J-domain chaperones from different host species and a protein denominated At-4/1 from Arabidopsis thaliana showing homologies to myosins and kinesins were identified as NSm-interacting partners. In this communication we illustrate that following TSWV infection, J-domain proteins accumulated in systemically infected leaves of A. thaliana, whereas At-4/1 was constitutively detected in leaves of A. thaliana and Nicotiana rustica.

It is indispensable to have accurate and speedy method of nematodes detection considering their great deal of malignancy nematodes. For identification of Meloidogyne incognita genetic primers were designed and the procedure was attested by Polymerase Chain Reaction.

Effect of temperature on growth and antagonistic ability of Trichoderma spp. isolated from local strawberry culture and commercial product, against Rhizoctonia solani, strawberry pathogen, was studied in vitro. Trials were carried out twice, at 10, 25 and 30°C. Inhibitor effect was evaluated by radial growth measures of established duals on PDA's dishes, using Royse and Ries formula, to evaluate the percentage inhibition of radial growth. Design of dishes was a randomized complete block, considering 10 replicates. Data were analyzed statistically by two-way analysis of variance. The objective has been to determine the most competitive Trichoderma strain and the best temperature that produce the inhibiting effect on the pathogen growth. Local strain has the best behavior at 10 and 25°C.

The major insect pests on rice in Tanzania are listed and described. They are from five orders (Coleoptera, Diptera, Hemiptera, Lepidoptera and Orthoptera) and are discussed as stem borers, stem and root feeders, and leaf and panicle feeders. This review puts together the hitherto fragmented information available on the distribution, host range, biology/life-cycle and ecology, and the management measures of the insect pests of rice. Areas for future research are also mentioned.

Verticillium wilt causes serious losses in the cultivation of shade trees, especially Norway maple (Acer platanoides L.).In 1993 research was started aiming at the development of Verticillium resistant rootstocks for Norway maple. Efficientmethods to select and screen for resistance in maple were developed, leading to several large-scale selection experimentscarried out in the period 1994-1996. This resulted in a first selection of about 300 plants out of a total of nearly 20 000 seedlingplants. An attempt was made to propagate these plants vegetatively in order to develop small clones for resistancetesting. During this stage of the research many plants were lost because of failure to propagate. After a second screeningfor resistance 35 plants were selected for further examination. Vegetative propagation was continued and from 2000 onthe performance of about 15 clones could be tested on naturally infested fields as well as after inoculation. The resultsof the field test show a clear selection response with disease incidence in plants of the selected clones being 50% lessthan in the seedlings and the randomly chosen clones. Within the group of selected clones there was a substantial variationbetween the clones with some clones having no disease at all whereas in other clones some plants showed serioussymptoms. Results of the field tests will be presented and the possibilities for solving the Verticillium wilt problem inmaple by means of using clonal root-stocks that are resistant to Verticillium wilt will be discussed.

Pythium oligandrum Drechs. belongs to the order Oomycetes. It is parasitic on many fungi from the same or other orders. The antagonism of P. oligandrum is a multifaceted process dependent on the target species involved. P. oligandrum is nonpathogenic on 12 species of crops from six families. It does not attack their tissue but occurs on the root surface, predominantly in the regions of hypocotyl - taproot, together with plant pathogenic fungi. It utilises the root exudates and fungus hyphae on the root surface, including those of the plant pathogens, for its own support. A growth stimulation of plants was observed. P. oligandrum can be utilised for biological control on a wide spectrum of crop plants. Different methods of application have been developed. The effect of a mycoparasite preparation is more preventive.

Rice (Oryza sativa) seeds were analysed to determine their potential transmission of pathogenic and saprophytic micro-organisms. In four and three hundred lots (stocks) of seeds, in 1998 and 1999 respectively, proceeding from mechanical drying sheds, none presence of Pyricularia oryzae was detected. It did not happen that way for Drechslera spp., whose presence was detected in 8.3% and 28% of the lots, in 1998 and 1999; within these ones the affected seed average was 1.3% in both years. Fusarium sp. appeared in 41% and 48% of the lots, in 1998 and 1999, respectively; the affected seed percentage, within these lots, oscillated between 1.7 and 2.4%. Regarding Arthrobotris sp. and Curvularia sp. the percentage of both, affected stocks and affected seed within these ones, were lower than 2%. About saprophytic micro-organisms, Alternaria appeared in 51% of the stocks in 1998, and in 38% in 1999, while Nigrospora did it in 39% and 33%. The affected seeds average per stock was about 2%. These low seed infection percentage seems a consequence of the mechanical drying process, that disables parts of the inoculum seed. On the other hand, harvested grain samples from trials established to promote the infection of Pyricularia oryzae in 1998, 1999 and 2000, showed that this pathogen was not present in any of these three years, in line with the seed results mentioned above. However, Pyricularia was present in 55% of the harvested grain samples in 2001 trial, as well as in 40% of the seeds. Seed can be a way of transmission of fungi if proceed from campaigns with a high level of inoculum in field.

The occurrence and virulence of wheat yellow rust in Hungary was studied in the period of 1999-2001. Yellow rust in Hungary occurred only in traces in 1999, strongly spread and reached epidemic level in Röjtökmuzsaj (West Hungary) in 2000, and the epidemic explosion was in the whole country in 2001. Surveys of yellow rust showed the importance of pathotypes, whose virulence spectra (virulent for Yr2, Yr3, Yr6, Yr7, Yr8, Yr9, Yr17, YrA+, YrCV, YrSD) were able to math the unknown resistance genes. Among 78 Hungarian and foreign cultivars 29 were strongly infected by yellow rust.

Botrytis cinerea, the cause of grey mould, is a 1999 we conducted trials in order to analyse the efficacy of the pyrimethanil, cyprodinil and fenhexamide and to test sensitivity of B. cinerea to them in vineyard in which these ingredients had been applied intensively, but also in vineyards where they had never been used. Resistant B. cinerea strains to each ingredient were determined in both types of vineyards.

During 1997-1998, the reaction of the collections of winter and spring wheat varieties to Tilletia caries was determined. In both years the most diseased winter varieties were Simona and Sparta, the least diseased were Samara and Ilona. High variability in the level of infection was observed in some varieties (VIada, Estica, Regina, Vega). No winter wheat variety was completely resistant. The most diseased spring wheat variety was Alexandria in both years, while Grandur showed no infection. High variability in the level of infection was observed in the special trials with cv. Ina and Contra. In trials of the efficacy of seed dressing against T. caries and T. laevis there was variability only in the controls, but not in dressed variants.

The objective of this study was to establish the genetic relationship among cultivars commonly used as donors for resistance to Plum pox virus (PPV) in order to identify the putative sources of resistance to PPV. The plant material tested represented the European, Central Asian and Chinese ecogeographical groups of cultivated apricots as well as the wild Dzhungar-Zailij population of Prunus armeniaca L. Forty-eight native accessions as well as the resistant (or tolerant) cultivars Harlayne, Stark Early Orange (SEO), Goldrich, Vestar and two hybrid forms Vestar × SEO (LE 3276) and Velkopavlovická × SEO (LE 2904) were screened by means of SSR analysis. To elucidate genetic relationships among apricot germplasm, a dendrogram was produced using neighbor joining (NJ) analysis of Nei's pair-wise genetic distances over 14 polymorphic SSR markers. On the dendrogram, resistant cultivars were separated into two different clusters suggesting two different sources of resistance to PPV. As was expected from pedigrees, SEO, Vestar, LE 2904 and LE 3276 were grouped together in a cluster adjacent to the European cultivars. Resistant cultivars Harlayne and Goldrich were within another group containing Central Asian apricots and Dzhungar-Zailij form.

Surveillance on cyst nematodes in Slovenia started already in 1963. We have found Globodera rostochiensis for the first time in 1971 and for the second time in 1975 (two cysts). In 1999 cysts of yellow potato cyst nematode were found again. A small hot spot was detected along the Slovene Austrian border. Cysts of Globodera rostochiensis were extracted from samples taken in 1.6 hectare field. In 2001 we surveyed 194 fields with the surface of 468.29 ha. We discovered another hot spot of Globodera rostochiensis in the Central Slovenia. Cysts of Globodera achilleae are seldom discovered in Slovenia. During the period between 1980 and 2000 we extracted altogether 206 cysts. In 2001 we found three fields where we extracted at first seven cysts. With more detailed survey we extracted another 30 cysts. In a few soil samples taken from the imported potatoes from Italy we have intercepted cysts of Globodera pallida. For that reason shipments were returned. In a similar way in 2002 shipments from Croatia were returned because of G. rostochiensis presence. Specimens of Globodera rostochiensis and G. achilleae species found in Slovenia were morphometricaly handeled.

The antifungal activity of water extracts of dried leaves of folded blackberry (Rubus plicatus W. et N.), walnut (Juglans regia L.), black currant (Ribes nigrum L.), and aspen (Populus tremula L.) was assessed in the in vitro experiment. The tested fungi were Alternaria alternata, Botrytis cinerea, Rhizoctonia solani, Fusarium culmorum, F. oxysporum and F. solani. It was found that all tested extracts inhibited the development of A. alternaria and F. oxysporum, whereas the strongest inhibiting effect was exhibited by extracts of aspen (A. alternata and F. oxysporum), black current (A. alternata) and folded blackberry (F. oxysporum). The tested extracts had no effect on B. cinerea.

Forma specialis (f.sp.) pisi of Fusarium oxysporum infestates pea but on other crop does not cause. Physiological races of this fungus (races 1, 2, 3 and 6) are tested on differentiation selections of pea. In the mixture with Fusarium solani there was better differentiated the reaction of single races. Own method is based on the artificial infection of the pea with the mixture of conidia and mycelial fragments of the race of Fusarium oxysporum f.sp. pisi and Fusarium solani. The roots of germinating pea are partially shortened on the top and poured with the suspension of fungi. After the germinating the infected pea is placed into Perlit (the substance for the cultivation). The pea was watered after that. During 3 years of our work we tested namely many new selections from the breeding station in Lužany. It seems that some of them should be used for new selection of realy resistant varieties. In the year 1999 there were new selection relatively resistant: 595/32, 682/37, 238/847, in the year 2000 no resistant selections were gained and in the year 2001 there were like resistant evaluated these selections: 633/1409 and 1456/1919.

It is well established that race-specific resistance selects for the specifically matching genes effecting virulence in the pathogen. As well, the use of different R-genes in time makes virulence complexity, VC (the number of virulences per pathogen genotype), to increase. Moreover, it becomes obvious here that the wind-dispersed cereal rusts and mildews are obligate nomads and highly mobile. As a consequence of these points and as a result of modelling, VC was expected to increase in the direction of predominant winds, e.g. from west to east across Europe, and it did by approximately one or more virulences per 1000 km. Starting from the barley mildew pathogen, comprehensive evidence is also available from leaf rust on wheat covering some 5000 km from Western Europe into Siberia. The impact of our findings for population genetics across Europe and Asia is supposed to be considerable and worth further elucidating, e.g., within the 6^th EU Framework Programme.

It was showed that gums induced by Fusarium oxysporum f.sp. tulipae in tulip bulbs applied to mineral Czapek-Dox Broth with Bacto Agar (CzDA) medium, containing sucrose substantially stimulated abundant growth of mycelium and sporulation of the pathogen. Addition of arabinose, xylose and their mixture, sugars occurring in tulip gum polysaccharide, to CzDA medium caused that mycelium was very sparse and sporulation was only slightly stimulated by arabinose. Mycelium growth on mineral CzDA medium without sucrose, was poor and sparse but addition of gum to the medium caused formation of abundant mycelium and increased sporulation of the pathogen. It is possible that polysaccharide of tulip gum may act mainly as elicitor and partially as substrate in regulation of mycelium growth and sporulation of Fusarium oxysporum f.sp. tulipae.

During trials (1998-2001) in the strawberry's plantation of the cv. Marmolade we monitored the appearance of the most important fungal diseases, their biology and possibilities of integrated control. Monitoring the biology of the determined fungi we established the way of overwintering, appearance of fruiting bodies and discharging of spores as well as beginning of primary infection and first symptoms of the following fungi: Mycosphaerella fragariae, Diplocarpon earliana, Gnomonia comari, Phomopsis obscurans on leaves and Botrytis cinerea on fruits. While checking the efficacy of fungicides, those most effecting to leaf diseases were Folicur Multi and Quadris, and on B. cinerea Switch and Teldor. Testing the resistance on botryticides the fungus B. cinerea showed low level of resistance to anilinopyrimidines and phenilsulfamides and high level to dicarboximides.

Systemic induced resistance (SIR) in a plant enhances disease resistance to a broad spectrum of pathogens. Under climate chamber conditions, oxalic acid's ability to elicit SIR in tomato (Lycopersicon esculentum Mill.) against wilt caused by Fusarium oxysporum f.sp. lycopersici (Fol) was tested with a susceptible cultivar (Danish Export). Oxalic acid (OA) was sprayed onto the green part of the tomato plants, at concentrations 2.5, 5, 10, and 20 mM. Two days later, each plant was challenged with 10 ml of Fol suspension (10⁶ conidia/ml) inoculated into the soil around the root system. After inoculation, disease incidence (DI) was quantified visually to assess SIR expression. OA-induced resistance (concentration-dependent) by otherwise susceptible tomato plants was obtained.

Inula viscosa is a perennial plant native to the Mediterranean Basin. Extracts made from the shoots of this plant exhibited a strong fungicidal activity in vitro and in vivo. TLC analyses revealed at least 7 fungicidal compounds. Most are lipophilic. When such extracts were sprayed on the leaf surface of crop plants they effectively controlled downy mildew in grape, cucumber and tobacco; late blight in potato and tomato; gray mold in cucumber and tomato; and, powdery mildew in cucurbits and cereals. Field experiments conducted with grape vine and potato resulted in effective control of Plasmopara viticola and Phytophthora infestans, respectively. The data suggest that Inula viscosa is a useful source of herbal fungicidal preparations for agricultural use.

The incidence of Zucchini yellow mosaic virus (ZYMV) was monitored in the south Moravian region of the Czech Republic during 1997-2001. Crops of gherkin, squash, zucchini and cucumbers were found infected with ZYMV, manifested by symptoms of severe stunting and yellowing with deformed leaves and fruits. Twenty to eighty percent of infected plants were recorded. Six isolates of ZYMV from four localities were differentiated on indicator plants; three of them were maintained as being typical for differences in pathogenicity. Overwintered weed species were tested for the presence of the virus. ZYMV was detected by ELISA in one plant of Tripleurospermum maritimum out of 46 tested, and in two plants of Stellaria media out of 29 tested in 2001. Such tests were repeated in 2002, and ZYMV was detected in three plants of T. maritimum out of 45 tested, in three plants of S. media out of 52, and in two plants of Trifolium repens out of 17 tested. The virus was successfully transmitted from T. maritimum, S. media and T. repens to indicator plants of Cucurbita pepo convar. giromontiina. Back-transmission of ZYMV was proved by ELISA, electron microscopy and symptoms. T. maritimum was found to be a new natural host of ZYMV.

Isolates of Fusarium oxysporum f.sp. ciceri from chickpea (Cicer arietnum L.) can be characterized as races and wilt and yellowing pathotypes by pathogenicity tests on varieties of differentials chickpea. This study shows that, DNA bands generated by RAPD-PCR can be used to assign Fusarium oxysporum f.sp. ciceri isolates to pathotype and pathogenic race.

The main objective of this study was to determinate the occurrence and intensity of attack by the more important fungal diseases on soybean in Eastern Croatia. Four-year investigation (1998-2001) was undertaken on 10 domestic soybean cultivars with different level of disease resistance. The investigation was set in two planting date (optimal and delayed) on experimental fields of the Agricultural Institute Osijek. Following more important diseases were established: Downy mildew, Pod and stem blight and Stem canker. Significant differences in disease incidence were caused by genetic diversity of tested materials as well as different climatic conditions among growing seasons. According to planting date, significantly higher incidence of Downy mildew and Pod and stem blight was in optimal planting date.