In view of the ecological hazards of chemicals, pot experiments were conducted to determine the efficacy of Trichoderma sp. against Macrophomina phaseolina. Greenhouse evolution of the interaction between M. phaseolina isolates and Trichoderma sp. isolates revealed a very highly significant (p = 0.0000). M. phaseolina isolate x antagonist isolate interaction for all the following parameters: preemergence damping-off, postemergence damping-off, survival, plant height, and dry weight. This interaction implies that a single isolate of antagonist can be highly effective againstan isolate of M. phaseolina, but may have only minimal effectsonotherisolatesof M. phaseolina. Therefore, isolates of antagonist should be tested against as many isolates of M. phaseolina as possible, as this will improve the chance of identifying antagonist isolates effective against several isolates of M. phaseolina.

Four tomato (Lycopersicon esculentum Mill.) varieties commonly grown by tomato farmers in Tanzania were evaluated for resistance to bacterial speck (Pseudomonas syringae pv. tomato) and bacterial spot (Xanthomonas vesicatoria) diseases, along with five introductions under screenhouse and field conditions. The four tomato varieties were Cal J, Moneymaker, Tanya and Roma VF. Seeds of the tomato varieties were purchased from seed vendors in the open market. The introductions that were included in the study were Bravo, Taxman, Stampede (from Sakata-Mayford Seeds (Pty) Ltd, South Africa), Torquay and BSS436 (from Bejo Zaden B.V., The Netherlands). In the screenhouse, results indicated that all the tomato varieties were susceptible to the two diseases, and suffered moderate to severe infection levels. The performance of the introductions against bacterial speck under screenhouse conditions was variable. All the introductions showed high levels of susceptibility to bacterial spot. Under field conditions, incidence of the diseases was high in all the locally available varieties tested, averaging 87% for bacterial spot and 82.3% for bacterial speck. The results of this study indicate that all the locally available tomato varieties included in the study were highly susceptible to bacterial speck and bacterial spot diseases.

Characterisation of two-spotted spider mite ( Tetranychus urticae Koch , Acari: Tetranychidae) response to aqueous extracts from selected plant species. Aqueous extracts from four plant species of known insecticidal activity on arthropods were tested against two-spotted spider mite females to describe their mode of action on the spider mite. The extracts effects on: (a) the mite establishment on host plant; (b) initiation of feeding (probing behaviour); (c) initiation of permanent feeding and (d) the mite mortality (a toxic effect) was measured using various experimental techniques. The highest toxic action was shown by NeemAzal-T/S (an extract from Azadirachta indica; production of Trifolio-M GmbH company) and repellent by water extract from Allium sativum and Urtica dioica. NeemAzal T/S also shown a strong activity as a feeding suppresant for T. urticae.

Phytophthora citricola constituted about 70% of all Phytophthora isolates recovered from rhododendron leaves used as baits for detection of that group of organisms in water. The species was found in 4 rivers, 2 hardy nursery water reservoirs and nursery drainage canal from May to October, 2006. Analysis of spots’ number on rhododendron leaf baits as a measure of P. citricola density showed that place of holding baits had a significant influence on the species occurrence. Significantly more spots, especially in July survey, were observed on baits held in Skierniewka and Zwierzynka rivers swimming through agricultural and forest area than in Ner, the river of horticultural area. Significantly more spots/rhododendron leaves were observed when they were held in rivers downstream of nursery and in the middle of hardy nursery borders. In nursery water containers and drainage canal higher Phytophthora density was recorded in August than in other periods of surveying. Using water from reservoir for sprinkling of Picea omorika nursery trees caused the development of tip blight and from diseased twigs P. citricola was isolated.

A total of 15 isolates of B. tulipae collected from home grown tulips without chemical protection and two commercial tulip plantations were examined by RAPD fingerprint analysis. The first tulip plantation was protected by bulb treatment and foliage spraying with fungicides in the growing period and the second plantation – only by the application of fungicides in the growing period. In the previous study, a set of isolates obtained from a plantation with an extensive use of fungicides demonstrated a higher pathogenicity level measured by the inhibition of plant growth, the percentage of bulb and root necrosis in flower pot tests on forced tulips, and by the necrosis size in tests on leaf disks. The relationships between the groups and among isolates were determined by cluster analysis of mean character differences using UPGMA and NJ methods. Similarity index values ranged from 0.872 to 1; on average, the index value was 0.933. A mean similarity of genotypes indicated the highest genotype uniformity of isolates obtained from a plantation with the extensive use of fungicides. 3 groups of clusters, could be observed in the obtained dendrograms. The first cluster contains exclusively genotypes of isolates obtained from a plantation with an extensive use of fungicides, the second one only genotypes of isolates obtained from a plantation protected only by the application of fungicides in the growing period and the third – one genotype of previous group of isolates and four genotypes of isolates obtained from home grown tulips without chemical protection. The most distinct differentiation between the groups of isolates was observed by the amplification using primers G4, H20 and J13. The results of this study revealed genetic similarity between isolates which were obtained from chemically protected plantations and demonstrated a higher degree of pathogenicity in comparison to the isolates which were obtained from unprotected plants and showed a lower degree of pathogenicity.

The investigations were carried out in 1996–2005 on the fields of Agricultural Experimental Station Department of SGGW Chylice in Mazowieckie voivodeship. The occurrence of diseases was assessed in 1996–2000 on winter wheat cv. Kobra, and in 2001–2005 on cv. Mikon. Weather conditions in ten-year experimental period were differentiated and had a distinct influence on plant infection by pathogens, as well as on the level of winter wheat yielding. In the first part of experimental period (1996–2000) the weather was characterized by higher temperatures compared to long-term average and higher amount of rainfall, with the exception of the year 2000 when the summer drought occurred. The highest for that period grain yield (54.70 dt/ha) was obtained in 1998. This was related to the lowest total infection of leaf surface area (22.76%) and a relatively low index of infection of stem base by Tapesia yallundae. In that year mass of 1 000 grain was also the highest. The lowest grain yield (40.80 dt/ha) was recorded in 2000 due to summer drought. In 1997 characterized by a high level of infection by T. yallundae (eyespot) obtained grain yield was also relatively low. In the second part of the experiment conducted on cv. Mikon (2001–2005) the lowest grain yield was recorded in 2001 (28.85 dt/ha) when per cent of leaf area infection of 2 upper leaves by Puccinia recondita (brown rust) was very high (44.79%), and the highest yield was obtained in 2003 (57.27 dt/ha). This was due to a moderate level of total leaf infection (30.21%) with fungal pathogens and favourable weather conditions for wheat development. In that year mass of 1 000 grain was also the highest. The occurrence of stem base infection by Fusarium spp. was maintained in the years 1996–2005 on differentiated level and it was lower in earlier years compared to the later period. The infection of ears by Leptosphaeria nodorum and Fusarium spp. was usually not high and its influence on the amount of grain yield not clearly evident. Chemical control of diseases influenced grain yield increase which was the highest in 2001 when winter wheat leaves were heavily infected by Puccinia recondita. The yield increase on fungicide treated plots was in that year 53.15%. It was evident that brown rust may pose a serious threat to winter wheat in the years of its high occurrence.

The objective of the study was to determine the effect of leaf wetness period and air temperature on development of disease symptoms caused by Puccinia recondita on winter wheat. The experiments were carried out in growth chamber at the Institute of Plant Protection in Poznań. Seedlings of a susceptible winter wheat cultivar Mikon, were artificially inoculated with urediniospores of P. recondita and incubated in temperature of 15 and 20°C. The period of duration of leaf wetness varied from 2 to 14 hours. Disease symptoms on seedlings at 20°C appeared 7 days after inoculation. Reduction of temperature to 15°C resulted in the elongation of latency period to 8 days. The relationship between leaf wetness period and disease symptoms severity was also observed. The gratest number of urediniospores in both tested temperatures were observed on plants exposed to 14 hours of leaf wetness. In temperature of 20°C 4 hours of wetness duration was enough to guarantee infection and the appearance of P. recondita pustules, whereas in 15°C at least 10 hours of wet period was needed to cause disease symptoms development. The experimental results were used to produce two equations describing relation between leaf wetness and symptoms development in tested temperatures.

Stem base health of spring barley cultivated under organic, integrated and conventional systems and fungal communities were studied. A worst plant health status was observed in the organic system. The macroscopic and subsequent mycological analyses revealed the occurrence of Bipolaris sorokiniana and Fusarium spp. The incidence of B. sorokiniana on stem bases was clearly dependent on a farming system, and the highest incidence of this pathogen was observed in the organic system. Also, in that system, Fusarium spp. were isolated more numerously in the beginning of tillering, but in dough stage B. sorokiniana was the most prevalent pathogen, and Fusarium spp. were more numerous in integrated and conventional systems. It is worth to note that organic conditions could be favourable to Gliocladium spp. Because of growing interest in ecology, excluding the use of pesticides and increasing popularity of biological disease control, these antagonistic fungi could be useful in organic systems.

Highly active antagonistic actinomycete Streptomyces griseoviridis and entomopathogenic fungus Beauveria bassiana were applied to the soil separately and together (in association) in the laboratory experiments. We assessed survival rate, insecticidal and fungistatic activity of these strains. We also tested the influence of synthetic insecticide Regent 25® (fipronil 25g/l) on investigated parameters. Additionally, insecticidal activity of both strains was compared with insecticidal activity of Regent. It was shown that both strains, especially S. griseoviridis, good survived in soil. Population density of S. griseoviridis in the association with B. bassiana increased 2–3 times compared to initial density. Regent considerably reduced population density of S. griseoviridis and B. bassiana. Insecticidal efficiency of S. griseoviridis was comparable with the effect of synthetic incecticide Regent and reached 89.2% and 86.8% respectively. Fungistatic activity towards Fusarium oxysporum showed only S. griseoviridis and it was observed that this activity decreased in time course.

The effectiveness of 7 fungicides ( Amistar 250 SC, Bayleton 5 WP, Bumper 250 EC, Discus 500 WG, Folicur BT 225 EC, Folicur Multi 50 WG, Score 250 EC) and 2 bioproducts (Biochikol 020 PC and Biosept 33 SL) in the control of Puccinia pelargonii-zonalis was tested on pelargonium cv. Pulsar F1 Salmon. Additionally, their influence on plant growth, size of pustules, percentage of germinated spores and phytotoxicity were assessed. Plants were sprayed 4 times at weekly intervals. Among tested compounds the most effective in suppressing new uredia formation were Amistar 250 SC, Bayleton 5 WP, Biosept 33 SL, Bumper 250 EC, Folicur BT 225 EC and Score 250 EC. Furthermore, some fungicides inhibited germination of urediospores on PDA medium. Fourteen days after the last spraying more than 76% of germinating urediospores were found on control leaves. At the same time spores collected from plants protected with Amistar 250 SC, Bayleton 5 WP, Folicur BT 225 EC and Folicur Multi 50 WG germinated sporadically in 1.5 to 4.0%. In the next part of experiment, plants with visible sporulation of P. pelargonii-zonalis were sprayed with tested compounds. After 1, 7 and 14 days of incubation, total number of spores and number of germinating spores were counted. After 1 or 7 days, urediospores collected from untreated plants germinated in more than 80% whereas from plants sprayed with tested fungicides except Amistar 250 SC in 20–66.6%. Amistar 250 SC was the most effective in suppressing urediospore germination. All fungicides used in protection of young pelargonium plants, except Amistar 250 SC and Biochikol 020 PC, decreased plant growth. None of tested compounds showed phytotoxicity toward tested pelargonium cultivar.

Field surveys were undertaken in 1997–1999 across five ecological zones in Nigeria to collect isolates of Maize streak virus (MSV), genus Mastrevirus. Apart from maize (Zea mays L.), 15 other grass species were found with MSV symptoms in Nigeria. These hosts showed two types of symptoms viz: mild (with or without mottle) or severe (typical symptoms in maize). When Cicadulina storeyi China was used to attempt transmission of these isolates of MSV to seedlings a susceptible maize hybrid CML 254 X CML 247, six isolates were not transmissible to maize. Seven isolates that were transmissible to maize produced mild symptoms. The viral agents causing typical or severe streak symptoms in Axonopus compressus (Sw.) P. Beauv., Brachiaria distichophylla (Trn.) Stapf, Dactyloctenium aegyptium (Linn.) P. Beauv. and Setaria barbata (Lam.) Kunth produced symptoms that were typical of MSV in farmers fields, when transmitted to maize. Out of 33 plant species that seedlings were challenged with MSV, only eight proved susceptible. Four of them showed mild symptoms while the other four showed severe symptoms of MSV. Only three isolates collected during the surveys did not react with a MSV polyclonal antiserum produced in mice in Double Antibody Sandwich-Enzyme-Linked Immunosorbent Assay (DAS-ELISA). These isolates were found in Andropogon gayanus Kunth (from Kaduna), Thelepogon elegans Roth ex Toem & Schult (from Kadawa) and Rottboellia cochinchinensis (Lour.) Clayton (from Jos) exhibited mild streak/mottle symptoms. Specific monoclonal antibodies, raised against MSV, reacted with 12 out of 25 samples tested. The DAS-ELISA data also showed significant variation in concentration of the virus in the different plant hosts. The relationship dendogram through SDS-PAGE among eight purified virus isolates show 55–90% variation. At 0.55 coefficient of similarity, the dendogram divided the samples into two groups while at 0.9 coefficient of similarity, the 8 isolates were identified as distinct genetic entities.

Mycoherbicides are special biotechnology products which contain fungi or fungal metabolites as nonchemical alternatives thereby reducing the input of harmful chemicals to control noxious weeds. The present communication emphasizes on the potential of an indigenous isolate of Alternaria alternata ITCC 4896 as a mycoherbicide for the global weed – Parthenium hysterophorus. Of the various spore concentrations tested by in vitro Detached Leaf Bioassay, 1x10⁶ spores/ml was the most effective inducing 89.2% leaf area damage on the 7th day and was further tested by Whole Plant Bioassay. Both in vitro Detached Leaf Bioassay and Whole Plant Bioassay exhibited a similar trend in disease development showing 50% damage at 96 hours post treatment. However, 100% mortality was observed in the Whole Plant Bioassay on the 7th day. This is the very first report on the bioweedicidal potential of A. alternata ITCC 4896 (LC#508) for use as a mycoherbicide for P. hysterophorus.