The insecticidal and antifeedant activity of extracts derived from different plants of the Liguidamber orientalis Mill. (Hamamelidaceae), Tanacetum vulgare L. (Compositae), Achillea coarctata Willd. (Compositae), Buxus sempervirens L. (Buxaceae), Diospyros kaki L. (Ebenaceae), Arum italicum Mill. (Araceae), Achilea biebersteinii Willd. (Compositae), Origanum vulgare L. (Labiatae), Hypericum androsaemum L. (Hypericaceae) and Ocimum basilicum L. (Labiatae). are reported. The 70% alcohol extracts of plants were tested for toxicity against the 3–4th instar larvae of the Yponomeuta malinellus Zell. (Lepidoptera.: Yponomeutidae). Antifeedant activity of the extracts was assessed through tests conducted on the larvae of Y. malinellus by the feeding protection bioassay. In tests carried out on the larvae of Y. malinellus, L. orientalis, O. basilicum and A. coarctata extracts showed high toxicity within 48 hour LC₅₀’s of 75, 75 and 65% respectively. The toxicity effects of the other extracts were determined as 60, 50, 50, 50, 45, 45 and 40% within the same period, respectively. No mortality was noticed in control groups. Alcohol extract from L. orientalis, T. vulgare and B. sempervirens showed high antifeedant activity (80.90, 46.12) on the larvae of Y. malinellus. In addition to both T. vulgare and L. orientalis extracts caused decrease consumption of food per 1 mg of larvae body weight decrease showed high –8.465, –0.845, mg respectively. The highest consumption (557.6 mg) was observed with alcohol extract from, D. kaki whereas the minimum one was using alcohol extract from L. orientali. The other tested extracts showed similar activity.

During the years of observations pedatory arthropods of Arachnida, Chrysopidae, Heteroptera, Coccinellidae, and Syrphidae were collected from Myzocallis coryli Goetze colonies. Arachnida constituted the most numerous group followed by predatory bugs of Heteroptera.

Genotypic differentiation among 10 isolates of Phytophthora cinnamomi Rands and 24 isolates of Phytophthora citricola Sawada from 12 different plant species grown in Polish ornamental nurseries was determined. DNA was extracted from pure pathogen cultures and amplified by the PCR technique using ISSR and RAPD primers. 9 primers were used to amplify P. cinnamomi and 8 to amplify P. citricola DNA. The analyzed amplification products were between 300 and 2300 bp. The genotypical differentiation was from 17 to 35% in P. cinnamomi and from 10 to 60% in P. citricola. Isolates from host plants of the same family showed, with some exceptions, similar levels of differentiation.

Research performed in the years 1999–2002 was carried out in Great Poland region on varieties of winter wheat Elena and Tercja. Experiments included three programmes of wheat cultivation: 1 – Conventional winter wheat protection based on recommendations for commercial fields; 2 – Integrated pest management programme where the control of diseases and insect pests was carried out on the background of thresholds of harmfulness/noxiousness, and weather forecasts; 3 – Untreated, without protection against diseases and pests. Two levels of nitrogen fertilization were applied in the experiments (120 kg N/ha and 170 kg N/ha) and the newest plant protection products were used for controlling fungal pathogens and noxious insects. The occurrence of diseases and insect pests, as well as beneficial entomofauna was determined in relation to each experimental variant, and occurring changes were analysed. Effectiveness of disease and pest control were calculated. Grain yield and its quality were determined and economical profitability for both conventional and integrated programmes calculated. It was shown that a high profitability can be obtained through the application of integrated pest management, as a result of correct choice and application of plant protection products, as well as proper choice of wheat cultivars and appropriate nitrogen fertilization.

The herbicide atrazine was incorporated in the granules manufactured in the process of tumbling agglomeration to obtain controlled release (CR) formulations. The formulations contained bentonite as a CRmatrix forming agent (960–974 g/kg of dry granules), atrazine (10 g/kg), citric acid (3.2 g/kg), and sodium alginate as a matrix binder and a release modifier (12.8–26.8 g/kg). The release characteristics of atrazine were studied by immersion of the granules in static water. The effects of formulations on atrazine transport through soil were studied using model soil columns irrigated with water. The release of atrazine from CR granules into water was affected by increasing the alginate concentration in a particular formulation because the time necessary for the release of 50% of the active ingredient was longer for the granules containing a higher amount of alginate. The CR formulations significantly reduced the amount of atrazine leached to the soil surface horizon in comparison with the commercial water suspension of the herbicide.

In the years 2000–2003 under Polish climatic conditions early blight occurred at different level of incidence on over 90.6% of surveyed fields. Time of disease appearance in different regions was closely related to climatic conditions. On average, early blight appeared on potato plants 59.3 days after planting, earlier than late blight. In the years 2001–2003, efficacy of six selected fungicides in early blight control was examined in field conditions. Experiments carried out in the Department of Potato Protection and Seed Science of Plant Breedingand Acclimatization Institute. Field trials located in two sites – at Bonin and Stare Olesno revealed much slower development of early blight on these fields where chemical protection was applied as compared to untreated control. Efficacy of plant protection program carried out in Bonin over three years varied from 40% to 63.9%. Effectiveness of selected products was higher in Stare Olesno at higher infection pressure, and ranged from 49.8% to 66.6%. However, efficiency of chemical protection in early blight suppressing is not as satisfactory as in late blight control. In field experiments good control of early blight resulted in tuber yield increase. In Bonin yield increase varied from 5.5 to 24.2% and in Stare Olesno from 12.2 to 34.4%.

Studies on palatability of some commom weed species, herbaceous plants and oilseed rape to D. reticulatum, A. lusitanicus and A. rufus slugs have been carried out under laboratory conditions. In food choice trials the rate and degree of damage to seedlings and leaf disks were determined for 20 plant species. The conducted experiments have also permitted to establish, which plant species were preferred or were not accepted by particular slug species. It was found that the studied slug species preferred seedlings and leaves of Brassica napus and Papaver rhoeas, but showed no preference for Epilobium hirsutum, Geranium sanguineum and Saponaria officinalis plants. As to the remaining plant species under study, the preferences exhibited by particular slug species were quite diverse.

Studies on food preference of herbivores include no-choice test and test with choice or multiple choice. Conclusions from statistic analyses of these tests are compared descriptively. The definition of compatibility index and consumption growth index has enabled us to use nonparametric test for verification of hypotheses about homogeneity of the consumption growths of selected plant species under no-choice and multiple choice conditions. The studies were conducted on food preference of the slug Deroceras reticulatum. It has been found that Chamaenerion angustifolium, Geraniumpusillum and Potentilla anserina can be used to reduce this slug feeding on cultivated plants. It has been also found that seedlings of Polygonum aviculare can be used as alternative food for slugs.

Fieldexperiment with spring rape (Brassica napus var. oleifera f. annua) cultivars Star andLisonne was conductedin the years 1995–1999 at the vicinity of Olsztyn, Poland. The herbicides trifluralin (Triflurotox 250 EC), alachlor + trifluralin (Alatrif 380 EC), metazachlor (Butisan 400 SC) andclopyralid(Lontrel 300) were appliedin spring rape according to recommendations (Zalecenia 1993). The aim of this study was to estimate the effect of the herbicides on glucosinolates content in spring rape seeds. The obtainedresults revealedsignificant effect of meteorological conditions on glucosinolates content. The Star cv. was characterizedby higher level of these compounds in comparison with Lisonne cv. The adequate values were 15.96 μmol g^-1 of d.m. and 12.32 μmol g^-1 of d.m., respectively. It is evident on the base of the statistical analyses of the obtained results that herbicides modified glucosinolates content in seeds of both cultivars. The level of these compounds was increased as the effect of Triflurotox 250 EC use (data obtainedfrom three years investigations) and Alatrif 380 EC (four years) while Butisan 400 SC activity was unfavourable (four years).

Studies on occurrence and harmfulness of celery fly on Sosnowski’s hogweed plants were performed in 1999–2002 in three plots at Minikowo, Mochełek and Topolno. At Mochełek, Minikowo and Topolno 40.65, 39.42 and 32.14% ofleaves, respectively were occupied by generation I ofthe fly while 14.8, 18.12 and 10%, respectively by the generation II. Most mines were caused by generation I in 2000 and 2002 at Minikowo and Mochełek. Generation II was characterized by a low population density in all plots.