Abstract. In the trials conducted in 2000–2002, we examined possibilities for growing potato using different methods of pre-planting treatment of seed tubers. 
The varieties exploited were ‘Varajane kollane’ (early), ‘Piret’ (medium early) and ‘Ants’ (medium late). There were used the following ways of treatment for all varieties: PS – pre-sprouting, TT – thermal treatment and 0 – tubers not treated.
The dynamics of tuber yield formation during the vegetation period was significantly influenced by the weather. In terms of potato growth, weather conditions were the most favourable in 2001. The weather in 2000 and 2002 was not the most suitable for potato growth and development, and the yield in these years proved lower than the three-year average. 
The average results from the three years show that potatoes could not realise their full potential to reach maximum yield. Pre-planting germination and thermal treatment had positive effects during the entire vegetation period, the effect being stronger at the beginning and then gradually decreasing. 
Pre-planting treatment of seed tubers had a different effect on varieties with different growing times. 
A comparison between the varieties showed that ‘Piret’ and ‘Varajane kollane’ started to form tubers early and thus exceeded the development of the variety ‘Ants’ until the 60^th day of growth. ‘Ants’ reached its maximum yield, 47.0 t ha^-1, already by the 114^th day, followed by the fast-ripening ‘Varajane kollane’ and the medium-ripening ‘Piret’. Thermal treatment did not give any advantage in terms of total yield formation compared to untreated seeds, except for the pre-planting germination variant of the variety ‘Varajane kollane’, the total yield of which exceeded that of its untreated variant by 7.08 t ha^-1.

Key words: storage, variety, thermal treatment, pre-sprouting, dynamics, weather conditions

Abstract. The specific composition of the flea beetle Phyllotreta spp (Coleoptera: Chrysomelidae), time of its appearance and dynamics of its number on the summer rape cultivar Mascot were determined. During the observation period, 6 species of flea beetles were found: Phyllotretaundulata  Kutsch., Ph. nemorum L.,  Ph. vittata  (Ph. striolata), Ph. nigripes F. Ph. atra and Ph. vittula. First flea beetles appeared at the time of the sprouting of rape plants. In the course of the entire observation period, the most numerous of these was the small striped flea beetle Ph. undulata. Proportion of the other species not often exceeded 10%. Very warm and dry weather following the sprouting of plants caused a rapid increase in the number of the pests and the maximum number was reached in a short time. A somewhat larger number of beetles was found on the edge plots. The field was sprayed three times, using Fastac (alphacypermethrin). Although after the first spraying the number of pests had decreased to almost zero, one week later the number of beetles began to rise again. Ten days after the spraying, the number of pests in the control and the sprayed variant had become equal, 2.0 and 2.2 individuals per plant. The second spraying lowered the number of pests again  down to zero. At that time the plants were reaching the stage of  3-4 true leaves, the time when the growth rate is the fastest. The third spraying was primarily directed against pests damaging generative organs: pollen beetles and weevils, and at that time plants began to form secondary racemes, and primary racemes lengthened. For controlling of flea beetles spraying was no more necessary. 

Key words: summer rape, flea beetles, damage, chemical control 

 Abstract. Anthropogenic influence on surroundings has induced anthropogenic or technogenic biogeochemical anomalies, where sharp a increase in the content of chemical elements has been  established. Due to technogenic contamination, the amount of microelements in soils comes close to the level of macroelements that negatively affect plants, soil qualities and biota.
Appearance of technogenic biogeochemical anomalies depends on such activities as mining and manufacturing, exploitation of mines, metallurgical and chemical industries, which,  through the air and sewage, contaminate soils, the atmosphere, storage pools, the vegetational cover and other components of nature. The extent of technogenic pollution depends on industrial capacities of contaminating enterprises, the time of their exploitation and the working effectiveness of purifying constructions.
Regions considerably contaminated with chemical elements have been found to cover the area within a radius of 10–15 km, whereas in the direction of the dominating winds it has even reached 20–30 km. The zone is referred to as a technologically vastly polluted area where dominating chemical contaminants in  the soil threaten the entire soil biota as well as its agrophysical and agrochemical properties.
Our observations revealed that heavy metals from open-cast mines of the Ore Mining and Processing Enterprise were scattered by the prevailing winds throughout the environment within a radius of 8–12 km, and transferred, via irrigating waters, to agricultural arables dozens of kilometers away. 
Key words: microelements, heavy metals, soil types, arable lands, biogeochemical anomalies

 Abstract. The penetration resistance of different arable soils is quite different depending on the Estonian area. We are briefly introducing the results of our research on soil compaction, penetration resistance of different soils in Estonia, uptake of nutrients and changes of intracellular fluid pH of barley depending on soil bulk densities. These data were mainly collected in a research field (58º23´N, 26º44´E) of the Estonian Agricultural University, with different levels of soil compaction (10 levels) on sandy loam Fragi-Stagnic Albeluvisol (WRB) soil in 2001 and 2002. The investigated cultural plant was spring barley (Hordeum vulgare L.). In Estonia H. Loogus has studied changes of cellular fluid pH, depending on seedbed, by using  microelectrodes directly on plants by quick method. The effect of soil bulk density on cellular fluid pH of barley leaves generally depends of number of passes. The experiment showed also that a higher decrease in nitrogen content started at the same soil bulk density value as the cellular fluid pH quickly increased. If the soil bulk density was increasing up to level 1.52–1.54 Mg m^-3, the cellular fluid pH suddenly increased very quickly. Nitrogen assimilation change in plants of barley decreased at the same bulk density values as a remarkable increase of intracellular pH was observed.

Key words: soil compaction, soil bulk density, nutrients, nitrogen assimilation, cellular fluid pH 

 Abstract. Fire blight (Erwinia amylovora) is one of the most harmful diseases of the Rosaceae fruit trees. At the moment fire blight is absent in Estonia. This condition is proved by three years of monitoring surveys by taking and analysing 933 samples. 
The present article studies the possibility and danger of appearance of this bacterial disease in Estonia. 
General influence for fire blight are climatic conditions, and key factors for appearance of the disease are temperature and humidity during the flowering season of its host plants. 
Climatic conditions of 35 years (1966–2000) from two meteorological stations – inland Võru and coastal Lääne-Nigula were analysed. 
It became obvious that a possibility of appearance of  fire blight in Estonia has been  present most of the years studied. If fire blight already actively existed in an area, possibility of infection would be high in both the meteorological stations.
Danger of fire blight infection has existed in Estonia most years. Therefore it is necessary to protect the territory of Estonia with special regulations. This can be made possible by establishing a fire blight pest free area, or, in case Estonia joins the European Community, a fire blight protected zone in the whole territory of Estonia.

Key words: degree hour; four-day degree hour total; low, moderate, high, extreme infection risk; active canker, pest free area, protected zone

 Abstract. In the work soil organic carbon (SOC) and soil organic matter (SOM) contents of Estonian postlithogenic mineral arable soils are analysed by 13 soil groups, whereas the data are taken from the database PEDON. The SOC and SOM concentrations (g kg^-1) and pools
(Mg ha^-1) for Leptosols, Cambisols (3 groups), Luvisols (2 groups), Albeluvisols (3 groups) and Gleysols (4 groups) are presented separately for humus cover (HC) and soil cover (SC). On the basis of different soil type characteristics and their distribution, superficies the SOC and SOM pools for the whole Estonian arable land were calculated. It was revealed that in the studied part of Estonian arable soils or in arable SC (forming 85.8% of total arable land) 86.4 +/-13.1 Tg of organic carbon is sequestrated, from which 77.3% is situated in HC and 22.7% in subsoil. This quantity of SOC is sequestrated into 149 +/- 25 Tg SOM. The generalisation of the data received by different soil types, as well as elucidation of pedoecological regularities is performed on the background of Estonian postlithogenic soil matrix. The characterisation of HC quality is done on the basis of arable soils HC classification. 

Key words: arable soils, soil humus status, humus cover type, carbon sequestration, SOC and SOC concentration and pools, matrix of postlithogenic soils

 Abstract. The attractivity of nine compounds, allyl isothiocyanate (allyl IT), benzyl isothiocyanate (benzyl ITC), 3-butenyl isothiocyanate (butenyl ITC), 3-butenyl thiocyanate (butenyl TC), butyl isothiocyanate (butyl ITC), butyl thiocyanate (butyl TC), 2-phenylethan-1-yl isothiocyanate (phenetyl ITC), 2-phenyleth-1-yl thiocyanate (phenetyl TC), and 2-phenylethan-1-ol, was compared to the beetle genera Phyllotreta species. Field tests were performed on fields of wild crucifer plants and on the edge of an oilseed rape field. Test places were at Juuru in Northern Estonia, at Valgeristi in the middle of Estonia and at Matsi in Southern Estonia. In our tests, Phyllotreta spp were most attracted to butenyl TC and butenyl ITC; allyl ITC and other tested alkyl-TC, alkyl-ITC, aryl-TC and aryl-ITC had lower attractivity. Cylindrical traps with a large clued area were tested and are recommended for practical usage, capillary polyethylene dispensers are recommended instead of sachet type dispensers. Emission of substances from sachet dispensers is described in the article. 

Key words: Flea beetles, Phyllotreta spp., kairomone,  3-buten-1-yl isothiocyanate, 3-buten-1-yl thiocyanate, 2-phenyl-1ethyl thiocyanate, sachet dispenser, pest control

 Abstract. This study was carried out to investigate the occurrence of the genus Fusarium Link ex Fr. on cereal grain grown in Estonia and grain feeds made of the named cereal grain. Within the period of 1973–1981, occurrence of genus Fusarium was identified in 1,065 grain seed samples, and, within 1997–2001, in 29 samples of grain feed. Fusarium sp. was identified in 67–100% of the studied wheat samples, and, depending on the year, infection was detected in 13–67% of the seeds. In the case of rye, Fusarium species were identified in 38–86% of the studied samples and infection was found in 8–23% of the seeds, with barley the figures were 45–97% and 14–46%; and oats 55–100% and 15–65%, respectively. 
The study indicated that the infection spread more intensively when corn was lodged, as a result of rainy autumn and late harvest. 16 species and 4 varieties of Fusarium were found on seeds. According to the survey (in 707 samples), the most common species were the following: F. avenaceum (Fr.) Sacc., F. poae (Pk.) Wr., F. oxysporum (Schlecht) Snyd. et Hans., F. ventricosum App. et Wr., F. sporotrichioides Sherb. var. minus Wr., F. verticillioides (Sacc.) Nirenberg and F. culmorum (W.G.Sm) Sacc. Mycotoxin producing species F. avenaceum, F. poae, F. sporotrichioides, F. oxysporum, F. verticilliodes, F. sambucinum Fuck., F. equiseti (Corda) Sacc. and F. culmorum were detected in 50–60% of the studied samples.   As a result of the studies on domestic grain feed (29 samples) carried out within 1997–2001, Fusarium spp. was found in 51.7% of the samples, whereas Fusarium toxins were detected in seven samples out of nine. 31.3% of Fusarium isolates were highly toxic, and 37.5% were toxic on Bacillus stearothermophilus. One isolate of F. verticillioides, one of F. culmorum, F. tricinctum (Corda) Sacc. and two of F. sp. proved to be highly toxic. 

Key words: cereal grain, grain feed, Fusarium fungi, seed infection, mycotoxins, Bacillus stearothermophilus

 Abstract. The effect of different fertilizers on potato tuber yield and its quality was investigated at the Elmininkai Research Station of the Lithuanian Institute of Agriculture during 1997-1999. Potatoes of 10 varieties belonging to different maturity groups were grown on plots with different fertilization. The following potato varieties were investigated: the extra early ‘Venta’ and ‘Ukama’, the early ‘Voke’, the medium early ‘Mirta’ and ‘Karolin’, the medium late ‘Hertha’, ‘Saturna’ and ‘Agria’, and the late ‘Aistes’ and ‘Speci’. 
It was established that different fertilizers, varietal properties and meteorological conditions during the potato vegetation period significantly influenced the yield and  quality of different potato varieties. The highest potato tuber yields (20.1–29.6 t ha^-1) of all the tested varieties were harvested when one-component and complex mineral fertilizers with microelements had been applied, the lowest (14.6–21.7 t ha^-1) when manure (60 t ha^-1) had been used in spring. The highest starch and dry matter content had potatoes of the following varieties: the early ‘Voke’ (up to 16.3% and 22.6%, respectively), the medium early ‘Karolin’ (up to 15.6% and 21.8%, respectively), the medium late ‘Saturna’ (up to 17.4% and 23.7%, respectively) and the late ‘Speci’ (up to 16.3% and 22.6%, respectively). The 1998 vegetation period was the most favourable for potato tuber yield, and the 1997 vegetation period for the accumulation of starch and dry matter. The vegetation period of 1999 was the most unfavourable both for potato tuber yield and the accumulation of starch and dry matter.

Key words: potato, variety, fertilizers, chemical composition

 Abstract. Large White Butterfly, Pieris brassicae L. (LWB) is one of the greatest pests of cruciferous cultures in Estonia, and, in the years of its biggest abundance, it can destroy a significant part of a crop.  Many plants contain natural compounds that can repel and/or attract insects and protect neighbouring plants. This principle is used in a method known as companion planting. The aim of this paper was to establish to what extent it was possible to influence, by using companion plants, the oviposition intensity of adults of LWB on Brassica oleracea var. capitata f. alba.  Cabbage plots were surrounded, as a border around garden beds, by the following plant species: Salvia horminum L. (syn. viridis L), Chrysanthemum carinatum Schousboe, Tagetes patula L., Allium cepa L. or Calendula officinalis L. Companion plants were replanted on the experimental plots in two rows. On control plots only cabbage was growing. 
French marigold, T. patula and painted daisy, C. carinatum were oviposition repellent to P. brassicae - compared with the control variant; butterflies laid fewer eggs on cabbage of these variants. At the same time, flowers of T. patula were attractive to adults of P. brassicae as the butterfly fed intensively on the flowers. There were no butterflies on flowers of C. carinatum, allowing us to conclude that this plant was a repellent to adults of P. brassicae. Certain repellent effects of  painted sage, S. horminum,  appeared towards the end of the summer, when the plants were in full flower. Butterflies laid eagerly eggs on cabbage plants surrounded by calendula, C. officinalis and onion, A. cepa. Our experiments showed how important it is to reckon with a certain pest, the control of which is intended, in choosing plants for founding a garden with diverse vegetation.

Key words: Pieris brassicae, companion plants, oviposition repellents

 Abstract. The antennal sensilla of male and female ground beetle species Bembidion lampros Hbst., Bembidion properans Steph. and Platynus dorsalis Pont. (Coleoptera, Carabidae) were investigated by using a scanning electron microscope. The filiform antennae of  ground beetles consist of the scape, pedicel and 9 flagellomeres. Thirteen different sensillar types were distiguished. These were: four types of sensilla chaetica, two types of sensilla trichodea, six types of sensilla basiconica, pit-organs sensilla coeloconica, and small domes sensilla campaniformia. Sensilla chaetica 4 occur only on the antennae of P. dorsalis, and sensilla trichodea 1 only on the antennae of Bembidion species. No sexual differences in the types of sensilla were found on the antennae of these three species. The possible functions are discussed and three types of sensilla were considered as olfactory, sensilla trichodea 2 and sensilla basiconica 1 and 2. Olfactory sensilla trichodea 2 and sensilla basiconia 1 form clear dorsal and ventral sensillar fields on the flagellomeres, which seems to be common in ground beetles. 

Key words: ground beetles, Coleoptera, Carabidae, Bembidion lampros Hbst., Bembidion properans Steph., Platynus dorsalis Pont., antenna, sensilla, morphology, typology, number

 Abstract. The effect of nitrogen rates, time of nitrogen application, concentration of nitrogen, phosphorus and potassium in aboveground plant dry matter, stand population density, mean daily temperature, precipitation rate, growing degree days accumulated by plants at different growing stages and the duration of vegetative growth period on seed yield of Star, a cultivar of Brassica napus L., were studied in the field experiment. The seed yield was significantly affected by nitrogen rates of up to 120  kg ha^-1. Further increase in nitrogen fertilisation had only a little effect on the seed yield of spring oilseed rape. There was a possibility to prolong the nitrogen application time until the start of flowering. However, in poorest soils, especially under unfavourable growing and development conditions, late nitrogen application could be much less effective. Nitrogen concentration in plant dry matter at 4–5 leaf stage, at the start and end of flowering and at the seed development stage had a significant effect on seed yield of spring oilseed rape. Phosphorus concentration was not important in the second part of vegetative growth. Potassium concentration, on the contrary, in the first part. With an increase of stand population density to up to 170 plant m^-2 seed yield of spring oilseed rape was increasing. The increase in the duration of vegetative growth period and precipitation rate resulted in a higher seed yield. Meanwhile, the increase of mean daily temperatures and growing degree days had a negative effect on seed yield of spring oilseed rape. Presented regression equations could be used for a model for prognosis of seed yield of spring oilseed rape, based on agronomic and climatic factors.

Key words:  Brassica napus L., seed yield, nitrogen, NPK concentration, population density, temperature, precipitation, GDD 

 Abstract. Oat grain is indicated to be of great value, especially for its favourable effects on the health of humans and animals. Food and feed industries can utilise only fully developed and faultless oat grain that can be harvested from healthy, unattacked plants. Cultivating disease-resistant varieties seems to be an optimum alternative to chemical control. Growing of the resistant varieties is the most effective biological control of diseases. It is highly economic and ideal from the ecological point of view. Disease resistant varieties are the basic precondition for successful sustainable (organic) agriculture. Stem rust (Puccinia graminis Pers. f. sp. avenae Erikss. et Henn) and crown rust (Puccinia coronata Cda. f. sp. avenae Erikss.) are the potentially destructive diseases of oat crop in Estonian conditions. The effectiveness of resistance sources to Puccinia coronata and Puccinia graminis was tested in the framework of the European and Mediterranean Oat Disease Nursery (EMODN) at Jõgeva Plant Breeding Institute in 1996–2002. Highly resistant to crown rust were Pc-gene lines Pc 39, Pc 54-2, Pc 59, Pc 60, Pc 68 and Pen2xCAV1376. The greatest change in crown rust incidence was recorded for Pc 58 and Pc 61. These lines were completely free from disease infection at the beginning of the trial cycle, but, in 2001, were attacked at a moderate level (5–6 points in 9-point scale). The differential  ‘Pirol’ and the varieties ‘Alo’, ‘Jaak’ and ‘Edit’ of the Estonian Variety List lost resistance to crown rust in 1998. Effective stem rust resistance against Puccinia graminis f. sp. avenae were conferring Pg-gene lines Pg 15, Pg a and Rodney ABDH. The first report of virulence on Pg 13 in Europe was detected in the framework of EMODN trials in Estonia in 1993.

Key words: Disease resistance, disease incidence, oat crown rust, Puccinia coronata f. sp. avenae, oat stem rust, Puccinia graminis f. sp. avenae

 Abstract. Studies of amaranth (Amaranthus spp.) collections have been carried out at the Lithuanian Institute of Agriculture since 1978. During the period of 1998–2001, 13 varieties and populations of amaranth and some parameters of amaranth growing technology (sowing time, seed rate, row spacing, etc.) were investigated. The amaranth was grown in the six-course perennial grass breeding crop rotation after ploughed-in first year clover, sown after black fallow without additional fertilising and pesticides.
Preliminary amaranth growing technology was elaborated. The highest yield was produced when amaranth had been sown in the middle of May, at a seed rate of 2–4 kg ha^-1, with row spacings of 50 cm and thrashed dry after severe frosts (-3…-5°C). The technology needs further improvement, and it is especially necessary to investigate fertilisation of amaranth in ecological and conventional farming systems.
Three amaranth varieties – ‘Raudonukai’, ‘Geltonukai’ and ‘Rausvukai’ – were registered in Lithuania in 2001. It is necessary to continue selection of amaranth species and varieties best suited for local conditions and investigate possibilities for use of amaranth green material and seed for food, feed, and energy production.

Key words: amaranth, varieties, sowing time, seed rate, row spacing, chemical composition