Field experiments were carried out in 2006–2007. The occurrence and harmfulness of soil pests was investigated in relation to the type of soil. Tubers were heavily damaged by grubs, wireworms and cutworms. Soil pests were more abundant in heavier soils. It is recommended to avoid growing potatoes after fallow, due to arising risk of soil pest infestation.
The aim of the experiment conducted in 2006–2008 in Żelazna was to determine the degree of root damage caused by cutworms and their effect on root yield and its quality of two cultivars of sugar beet. The evaluation was performed including two different rotations (after sugar beet and after spring wheat) and different postharvest methods of tillage. Cultivation of sugar beet after sugar beet during 3 subsequent caused fourfold increase in the number and percentage of damaged roots by cutworms. Subsoiling significantly lowered the number of damaged roots by cutworms. Different variants of postharvest tillage did not influence the percentage of damaged roots per plot. Traditional postharvest tillage caused a significant increase of damage degree by cutworms. Percentage share of damaged roots negatively affected biological and technological yield of sucrose, and the degree of root damage negatively influenced root yield of sugar beet.
The effect of Sinapis alba cultivars on potato cyst nematode population in the soil was tested in field experiment in Bydgoszcz in 2007–2009. Nine varieties of white mustard were cultivated as catch crop in microplots. Before sowing and after the end of vegetation nematode population in soil was defined. The reduction of the nematode population in the soil depended on mustard variety and ranged between 29.8 and 55.8%.