Abstract
In 2003-2004, the influence of mulches of winter cover crops on the population of the cabbage aphid (Brevicoryne brassicae L.) in white cabbage production with two levels of N fertilization was investigated. Winter cover crops (rye, hairy vetch and their mixture) reduced B. brassicae population on cabbage by 86.1% to 100%. The level of nitrogen fertilization of cabbage had no effect on the aphid population. In addition, it was found that higher levels of nitrogen fertilization can cause an increase in the population of B. brassicae when cabbage is grown in bare soil.