engleski

The effect of fertilisers on the pests of oilseed rape

The consumption of petroleum products in Croatia and the rest of the world has been increasing. It is expected that the consumption of motor fuels will rise because of the rapid development of transportation, whereas the consumption of fuel for heating will decrease. One alternative to mineral fuels is biodiesel produced from various plant oils, beef suet and used cooking oils. The most important raw materials for the production of biodiesel are oilseed rape (82.82% of the total) and sunflowers (12.50%). As the areas of land devoted to oilseed rape and other crops for the production of biodiesel expand, so do the problems of protecting these crops from diseases, pests and weeds and discouraging pest resistance to pesticides. Fertiliser application is of great importance to achieve high yields. The objective of this research was to determine the effect of various quantities of fertiliser on the population density and abundance of the weevils Ceutorhynchus napi Gyllenhal, 1837 and Ceutorhynchus pallidactylus Marsham, 1802 (Coleoptera: Curculionidae) and Meligethes aeneus (Fabricius, 1775) (Coleoptera: Nitidulidae) on oilseed rape. The experiment was performed using the Triangle variety of oilseed rape at the Vinokovščak site (Varaždin, Croatia) in 2008. Fertiliser (nutrient KAN) was applied to the fields in three different quantities: 150 (lower quantity), 200 (optimum quantity) and 250 (higher quantity) kg ha-1. During the vegetation period, two visual inspections of the oilseed rape plants were made. Four samples were collected from each of the ten plants in each experimental field. The plants were dissected, and the number of perforations, the lengths of corridors and the numbers of C. napi and C. pallidactylus larvae were recorded. The results showed that there were significant correlations between pest attack and the differing quantities of fertiliser ; pest abundance increased with the amount of fertiliser applied. The data obtained show the need to analyse the total amount of nitrogen in the soil and to use fertiliser that corresponds to the actual concentration of nitrogen in the soil and to the nitrogen needs of the plant being sown.

fertilisers; pests; oilseed rape

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