Abstract: The study of the bionomy of privet sawfly (Macrophya punctumalbum (L.), a pest of park plants in the city of Poznań, was conducted during three vegetation seasons in the years 1981–1983, at the insectarium of the Department of Entomology at Agricultural University in Poznań. The aim of the study was to define the longevity and fecundity of imagines, larvae development of the species and the level of parasitizing the eggs of the privet sawfly by parasitoids of the Chalcidoidea superfamily. The sawfly occurred in the last ten days of May. The females lived from 4 to 36 days, most often quite short (73.3%), from 7 to 14 days. After reaching the stage of sexual maturity, which lasted mostly 8–9 days, they started laying eggs. The fecundity of females fluctuated between 1 and 122 eggs. The mean female fecundity was 52 eggs. It was found that the larvae of sawfly went through 5 instar stages. The parasitoids of the Chalcidoidea superfamily decreased the abundance of the sawfly at the egg stage from 0.47% to 8.65%. Those were Anaphes cultripennis Debauche (Mymaridae) and Trichogramma sp. (Trichogrammatidae).

Abstract: The many years’ study on species composition and harmfulness of aphids infesting perennials in the decorative plant collection Agricultural University in Poznań permited to ascertain occurrence of 23 aphid species on 66 species of decoratice perennials, representing 20 botanical families. The species that occurred in all the four study seasons in 2000, 2002, 2003 and 2005 included: Aphis fabae Scop., Brachycaudus cardui (L.) and Aphis sedi Kalt.. Very often Aphis newtoni Theob., Acyrthosiphon malvae (Mosl.), Brachycaudus helichrysi Kalt. and Longicaudus trirhodus (Walk.) were found. Spring and early summer was the period of numerous occurrence of aphids on decorative perennials. The high degree of plant infestation was resulted in decreasing the plant’ decorative value. The aphid infestation may be especially dangerous for numerous cultivars of Dahlia x cultorum, Eryngium planum, Echinops ritro, Leucanthemum maximum, Papaver orientale, Sedum aizoon, Iris sibirica, Yucca filamentosa, Achillea ptarnica, Dicentra eximia, Doronicum orientale i Geum coccineum.

The studies conducted in the years 2004–2006 in a production orchard in the habitat conditions of the Sandomierska Upland showed that the trees budded on the seedlings of wild cherry grew more strongly than on Colt rootstock. No significant differences were observed between the rootstocks as for the trunk thickness and the crown size of young trees planted in 2001. In the group of trees planted in 1996, which were in the period of full fruiting, the crowns of trees budded on wild cherry were significantly bigger than on Colt rootstock. No significant differences were found out in the yielding of trees on wild cherry and Colt rootstock. Considerable differences in the yielding between the studied years in the group of young trees with systematic increasion was effected by increase of crown. ‘Kordia’ cv. is a valuable cultivar for Sandomierska Upland. It begins late the fruiting period (the first commercial yield in the fifth year after planting); however, it gives attractive fruits and high productivity of trees.

Studies were carried out in the years 2003–2004 in a greenhouse. Three nutrient solutions with differing contents of nitrogen and potassium for chrysanthemum fertigation were used. Influence of used fertilization on growth and development of plants data was very limited. No effect of the studied nutrient solutions on plant flowering term was found. For the fertigation of chrysanthemums from Time group grown from April till October in peat substrate nutrient solution containing 150–180 mg N-NO₃·dm^-3·and 210–252 mg K·dm^-3·is recommended.

Various forms of nitrogen fertilizer were applied in the cultivation of red cabbage (in the years 2003–2005), ‘Langendijker’ c.v.: control (unfertilized with nitrogen), Ca(NO₃)₂, (NH₄)₂SO₄, NH₄NO₃, CO(NH₂)₂ applied as solid fertilizers. This experiment aimed at determining the influence of various nitrogen forms on the content of Al, B, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Sr, Ti, Zn, V in cabbage heads and the changes in the content of the available form of these elements for plants in soil after cabbage cultivation. The heads of plants fertilized with calcium nitrate and urea were characterized by the highest content of Al, Mn, Sr, Zn, Cd and Mo. Urea caused a significant increase in the content of Cu, Li and V, while ammonium nitrate resulted in an elevated level of Fe and Co accumulation in cabbage heads. Fertilization with (NH₄)₂SO₄ led to a substantial decrease in the content of Al, Mo and V, and fertilization with NH₄NO₃ caused a decline in Sr concentrations in cabbage in comparison with other objects of the experiment. Each nitrogen fertilizer resulted in the decreased concentrations of Ti in cabbage heads. Applied nitrogen fertilizers significantly influenced the contents of readily soluble forms of B, Fe and Pb in soil after cabbage cultivation.

In the years 2004 and 2005, in an unheated greenhouse, an experiment was carried out with hot pepper ‘Wulkan’ cultivar. The purpose of studies was to determine the effect of nitrogen and potassium fertilization on the salinity of substrate in hot pepper growing and to show the dependence between the content of these elements in the substrate and in the indicator parts of the plant. Fertilization with nitrogen and potassium was differentiated in two levels: N 250 and K 300, and N 350 and K 400 mg∙dm^-3 substrate. It was found that a higher dose of nitrate and potassium caused an increase of EC in the substrate. A differentiated level of nitrogen fertilization had no effect on the nutritional status of hot pepper plants by this macroelement. On the other hand, potassium content in leaves was slightly higher with a higher fertilization level.

Vegetative experiments were carried out in the years 2002–2004 in two specialistic horticultural farms growing the most popular in Poland and in the Netherlands cultivars of anthurium (Anthurium cultorum Birdsey): ‘Baron’, ‘Choco’, ‘Midori’, ‘Pistache’, ‘President’ and ‘Tropical’. Plants were grown in expanded clay with the use of drop fertigation with standard nutrient for anthurium in inert substrates (in mg∙dm^-3): N-NH₄ < 14.0, N-NO₃ 105.0, P 31.0, K 176.0, Ca 60.0, Mg 24.0, S-S0₄ 48.0, Fe 0.840, Mn 0.160, Zn 0.200, B 0.220, Cu 0.032, Mo 0.048, pH 5.5–5.7, EC 1.5 – 1,8 mS∙cm^-1. Subject of studies was the differentiation of microelement content in drainage waters driped from the substrate in relation to the supplied nutrient. Manganese was the nutrient wich was most intensely decreased (by –65.5%), followed by iron (by –51.9%) and zinc (by –45.2%). On the other hand, an increase was found in copper (by +11.1%) and in boron (by +16.6%). The recognition of changes in the contents of nutritive components in the drainage waters is a basis for the elaboration and implementation into the horticultural practice of closed fertigation systems with nutrient recirculation.

Abstract: A vegetation experiment was carried out in the years 2006 and 2007, with Clematis from Jackmanii group, cultivar ‘John Paul II’. Two types of multicomponent fertilizers with slowed down action from Osmocote Exact group were used: Osmocote Exact Hi-Start and Osmocote Exact Standard. Influence of these fertilizers was studied on growth and yielding of Clematis ‘John Paul II’. The longest shoots of Clematis were obtained after the application to the substrate of Osmocote Exact Hi-Start and Osmocote Exact Standard fertilizers in the dose of 8 g∙dm^-3. Plants fetrilized with Osmocote Exact Hi-Start obtained the highest weight of their above ground plant parts at the dose of 8 g∙dm^-3 of substrate, while plants fertilized with Osmocote Exact Standard obtained the highest weight of their aboveground plant parts at the dose of 6 g∙dm^-3 of substrate. Plants in a 5-month period of growing with the application of the fertilizers Osmocote Exact Standard did not show any signs of mineral malnutrition. The greatest number of flowers and the greatest weight of flowers was found in plants grown in the substrate with an addition of the fertilizer Osmocote Exact Standard in the dose of 6 g∙dm^-3. The best fertilizer for the growing of Clematis ‘John Paul II’ cv. has shown to be Osmocote Exact Standard in the dose of 6 g∙dm^-3.

In pot experiments with lettuce, the effect of chelated and mineral forms of manganese on the fresh matter of plants and on the content of Mn, Cu, Zn and Fe in lettuce leaves were compared. Lettuce plants were grown in a peat substrate where the manganese content was differentiated in four levels: 10, 20, 30, and 60 mg Mn∙dm^-3. Independent of the form of the applied manganese, no differences were found in fresh matter of lettuce heads at manganese levels of 10 to 30 mg Mn∙dm^-3 substrate. When the plants were nourished with the mineral form of manganese, then in comparison with the chelated form of manganese, the content of manganese in lettuce leaves was higher. The differentiated fertilization with manganese exerted an effect on the nutritional status of plants with copper, zinc and iron. After the application of chelated manganese, there was more copper and iron in the lettuce, but a lesser amount of zinc than in case of manganous sulphate application. The increase of manganese content in the substrate caused an increase of this component in the plants.

In the field experiment with cabbage cv. ‘Menza F₁’ fertilized with 150 and 250 kg N·ha^-1, the first weeding started 3, 6, 9, 12 weeks after transplanting, including unweeded control. Higher dose of nitrogen especially in treatments with delayed weed control affected in significant increase of marketable yield, as well as the mean weight of cabbage heads in comparison to the dose of 150 N·ha^-1. The highest yielding was recorded in treatment where the first weeding was conducted 3 weeks after transplanting. The delay of this operation to 6, 9, and 12 weeks after transplanting caused the decrease in marketable yield by 16.0%, 33.1% and 48.4%, respectively. The dose of 250 N·ha^-1 contributed to the slight decrease of dry matter, total and reducing sugar contents, and higher accumulation of nitrates in edible parts of cabbage heads. Late start of weed removal was disadvantageous for dry matter and sugars content and caused higher nitrates accumulation in cabbage.