Sixteen tomato cultivars obtained from the collections of the Institute for Agricultural Research (IAR) Samaru, Nigeria were screened for resistance to local strains of Tomato leaf curl virus at Samaru, Northern Guinea Savanna, over a two year period, 1998/1999 and 1999/2000 dry seasons. Five cultivars were moderately resistant, nine were moderately susceptible, while two were highly susceptible. Most of the cultivars were high yielding (46–55 t/ha) and had good fruit size (4.8–6.0 cm x 2.8–4.1 cm). They will be further evaluated on-farm at different locations after which they will be introduced to farmers to replace the low yielding and TLCV-susceptible cultivars currently in use in most parts of the Savanna ecological zones of the country.

The effect of crude extracts of neem (Azadirachta indica) leaf, neem seed and garlic (Allium sativum) at concentrations ranging from 5% to 30% of the material in 100 ml of Potato Dextrose Agar on mycelial growth of Fusarium oxysporum f. sp. lycopersici was assessed. All the extracts inhibited mycellial growth at various levels. Dry neem seed extract gavel 100% inhibition of mycelial growth. Fresh neem leaf extract reduced mycelial growth with increasing concentration while in garlic there were no differences in growth inhibition among the various concentrations used. However garlic extracts decreased sporulation with increasing concentration and cultures grown on extract amended agar plates remained viable.

Powdery mildew caused by Blumeria graminis f. sp. hordei is one of the most important diseases of barley in Poland. B. graminis is a genetically diverse pathogen with different special forms and races. The aim of the two-years’ experiment was to assess of B. gramins f. sp. hordei virulence frequency and powdery mildew occurrence on four winter barley cultivars. Virulence frequency of the pathogen depended on place and term of exposition. The occurrence of powdery mildew on four winter barley cultivars depended on virulence frequency of the pathogen and weather conditions.

Vegetables in addition to arable crops and ornamentals are also at high risk from slug and snail attack at all growth stages. The no-choice tests were conducted under laboratory conditions to assess the harmfulness of the slug Arion rufus (Linnaeus) and the snail Cepaea hortensis (Müller) to young vegetable plants. Ten species representing leaf and root vegetables, allium, brassica, cucurbit and edible pulse plants were chosen to compare their susceptibilities to feeding of these pests (agrotechnical classification – Polish National List of Varieties of Agricultural and Vegetable Plants 2005). The evaluation of the growth of the tested vegetables included a percentage of the damaged plant area and changes in aboveground plant mass. The trend toward increase of mass was defined by the means of regression analysis. Losses of aboveground plant mass resulting from pest feeding and plant growth restraint caused by the slug or the snail damage were assessed. Variance analysis of the general linear model and orthogonal contrasts were calculated to compare the vegetable groups included in the research. The highest losses of aboveground plant mass, by both pest species A. rufus and C. hortensis, were on common bean plants and the smallest on plants of leaf vegetables (lettuce, dill), brassica plants (cauliflower, white cabbage) and allium plants (garden onion).

Influence of Fusarium oxysporum f. sp. cubense (E.F. Smith) Snyder and Hansen on 2,4-diacetylphloroglucinol (DAPG) production in the rhizosphere of banana cultivar Rasthali by Pseudomonas fluorescens was investigated. The purified extracts of Pfm strain of P. fluorescens isolated from banana rhizosphere inhibited the growth and spore germination of F. oxysporum f. sp. cubense under laboratory conditions. DAPG extracted from the cultures of the strain was observed as distinct spots in thin layer chromatographic plates at Rf value of 0.88. The extracts of soil inoculated with P. fluorescens and challenge inoculated with F. oxysporum f. sp. cubense eluted at retention time ranges from 20.00 min to 21.30 min. The quantity of DPAG production was less in the extracts of soil inoculated with P. fluorescens and challenge inoculated with F. oxysporum f. sp. cubense as compared to P. fluorescens alone inoculated soil. The talc formulation of Pfm strain also reduced vascular discolouration due to the pathogen in banana plants when inoculated at 15 g/plant.

The experiment was conducted in the years 2001–2003 at the Experimental Station in Złotniki. The aim of the performed investigations was to evaluate economic effectiveness of different fungicidal protection programs in winter wheat. Winter wheat of cv. Sakwa was cultivated using the following two variants of seed treatment: 1) Raxil 060 FS at the dose of 60 ml/100 kg grain, 2) Raxil 060 FS + Latitude 125 FS at the doses of 60 and 200 ml/100 kg, and five variants of fungicidal foliar protection: 1) Vista 228 SE, 2) Sportak Alpha 380 EC, 3) Sportak Alpha 380 EC + Vista 228 SE, 4) Sportak Alpha 380 EC + Vista 228 SE + Juwel 250 SC, 5) control – without protection. The use of the above plant protection products contributed to the increase of winter wheat grain yield from 0.60 t/ha to 2.07 t/ha. This increase of yield covered costs of performed chemical control. The economic analysis showed that most effective variant of winter wheat chemical protection was seed treatment with Latitude 125 FS with additional two foliar treatments with the following fungicides: Sportak Alpha 380 EC and Vista 228 SE. Irrespective of the applied seed dressing, additional application of Juwel 250 SC at the stage of early milk maturity turned out to be economically not justified.

The effect of biopreparation Biochikol 020 PC on linear growth of mycelia of two Rhizoctonia isolates was tested under laboratory conditions along with that of fungicide Baytan Universal 19,5 WS for comparative purposes. Complete retardation of mycelial growth of both isolates was observed in case the application of fungicide Baytan Universal 19,5 WS at the concentration of 0.1% and a considerable growth inhibition was stated at the temperatures of 10°C and 30°C. The effect of seed dressing with the above mentioned preparations on plant infestation by Rhizoctonia fungi was tested in a greenhouse experiment on two cultivars of spring wheat: Banti and Ismena. Baytan Universal 19,5 WS reduced plant infestation especially at the highest soil moisture content of 20 kPa. Biopreparation Biochikol 020 PC and diversification of soil moisture levels did not result in a reduction of wheat infestation rate. This biopreparation stimulated the increase of root mass of both cultivars at moisture content of 20 kPa.

The third record of Cinara tujafilina occurrence in Poland is given. The population dynamics of the species is presented.

In 1993–1997, 990 pupae of diamondback moth (Plutella xylostella L.) were collected from nine different varieties of Brasica oleracea L., grown on experimental farm near Kraków. Only 234 moths (23.6%) were recovered from the cocoons. The most important factor reducing the population of DBM was parasitization (65.1%). It varied between the years of observation and oscillated from 60% to 90.3%. Sixhundred and fourty four specimens of parasitic wasps belonging to 11 species from families: Ichneumonidae (5 species), Braconidae (3 species), Pteromalidae (2 species) and Eulophidae (1 species) were reared out. In each year of observations the most abundant species among DBM parasitoids was Diadegma fenestralis Holmgr. as it constituted 71.4% of all of the wasps reared. In the years 1994 and 1996 with low abundance of diamondback moth, D. fenestralis was the only species parasitizing 66.7% and 89.5% of the pest larvae.

The efficacy of some plant extracts on the control of potato tuber soft rot caused by Erwinia carotovora ssp. carotovora was evaluated in the laboratory conditions. Neem leaf and seed aqueous extracts significantly reduced the incidence and severity of tuber soft rot, while ironweed and Siamese cassia aqueous leaf extracts gave moderate control of the disease. Tuber treatment with river redgum aqueous leaf extract did not control tuber soft rot.

Field surveys were performed in winter and spring rape crops of agricultural companies and individual farmers during the period of 2001–2003. A questionnaire was completed for each experimental field, giving a description of the crop. The incidence and severity of fungal diseases were estimated annually in 14–18 winter and spring rape crops. Seed samples were taken from each field and composition fungal communities on harvested seed was estimated. Alternaria blight and Phoma stem canker were present on stems of all investigated winter and spring rape cultivars and Alternaria blight occurred on siliques in all experimental years. In 2001, most favourable year for spread of diseases, Alternaria blight damaged 87.2 100% of winter rape and 100% of spring rape siliques, maximum disease severity was 6.66 and 7.24%, respectively. All cultivars of winter and spring rape were susceptible to Alternaria blight. Phoma stem canker was more often found on stems of spring oilseed rape – up to 98% of stems with symptoms of Phoma stem canker. Seed fungal infection level was 10.0–100% in winter rape and 16.0–93.6% in spring rape seed samples. The most frequent fungi on seeds of winter and spring oilseed rape were Alternaria spp. and Cladosporium spp.