Oviposition by Mamestra brassicae (L.) (Lep., Noctuidae) in relation to age, time of day and host plant

The age at which females begin to lay, the daily pattern of oviposition, th e influence of host-plant material on egg-laying as well as the host prefer ence of Mamestra brassicae L. (Lep.. Noctuidae) were investigated under lab oratory conditions. The females began to oviposit during the third, fourth and fifth scotophase after emergence. A great variability in daily female f ecundity was observed. The highest level of oviposition occurred during the fifth day. Females oviposited during the whole scotophase, but maximal ovi position occurred during the second hour. The females without host-plant ma terial laid fewer eggs than females with host-plant material (cabbage leave s Brassica oleracea var, capitata). In two-choice tests, the females prefer red to oviposit on cabbage rather than chrysanthemum, but there was no diff erence in the mean number of eggs laid on cabbage and tomato. There were si gnificantly greater mean numbers of total eggs deposited on tomato than on chrysanthemum.