451 Effect of cultivar on oviposition preference of the cabbage moth, Mamestra brassicae L. (Lepidoptera: Noctuidae) A. Ploomi 1 , K. Jõgar 1 , L. Metspalu 1 , K. Hiiesaar 1 , E. Švilponis 1 , I. Kivimägi 1 , N. Men'shykova 1 , A. Luik 1 , I. Sibul 2 and A. Kuusik 1 1 Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia; e-mail: angela.ploomi@emu.ee 2 Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia Abstract. The oviposition preference of the cabbage moth, Mamestra brassicae L. (Lepidoptera: Noctuidae) was investigated on white cabbage cultivars under field conditions in two vegetation periods. Significantly less eggs were laid on cultivar ‘Golden Acre’. There were no differences in the number of eggs found on the cultivar ‘Lennox’, ‘Krautman’, ‘Krautkaiser’ and ‘Turquoise’. The cultivar ‘Parel’ showed different results during experimental period. The data on cabbage moth oviposition preferences can be used in sustainable plant protection strategies in organic farming. Key words: Mamestra brassicae, oviposition, white cabbage cultivars INTRODUCTION Cabbage (Brassica oleracea var. capitata) is an important vegetable crop grown extensively in temperate regions throughout the world. One of the major limitations in cabbage production is damage due to insect pests. The most important among them is a highly polyphagous generalist cabbage moth, Mamestra brassicae L. (Lepidoptera: Noctuidae) (Popova, 1993). Bretherton et al. (1979) reported that M. brassicae is particularly associated with cruciferous crops. M. brassicae hibernates as diapausing pupa in soil. The adults emerge in June, and the eggs are deposited in clusters on the underside of the leaves. Larvae in the instars I–IV feed mainly freely exposed on the outermost leaves. From instar V the display a negative phototaxis (Omino et al., 1973), and move into the crown of the plant. When the larvae are fully grown in August and September, they enter the soil where they pupate in earth at a depth of 3–5 cm (Rygg & Kjos, 1975). One M. brassicae female is able to produce about 1000 eggs in the laboratory, giving a potential for a population increase of 300% in each generation. Fortunately, there is a high mortality in early immature stages (Johansen, 1997). The occurrence of cabbage moth in Estonia is variable. During the last years, the population levels in general have been low, but with sporadic, local outbreaks. Commonly, in conventional farming, lepidopterous pests of cruciferous crops have been controlled by the use of insecticides. However, this is not the most desirable mean of control because cruciferous crops are used for human and animal consumption, which is why insecticides are prohibited in organic farming. Although Agronomy Research 7(Special issue I), 451–456, 2009