Influence of Host Plant Damage on the Host-Finding Behavior ofMamestra brassicae(Lepidoptera: Noctuidae)

Abstract

The influence of interspecific, intraspecific insect infestation, and mechanical damage of 3 host plant species on the attraction, landing, and oviposition of Mamestra brassicae (L.) was studied in a wind tunnel. The presence of aphids did not affect the attraction, landing, or oviposition of mated females. However, when plants damaged by female locusts were used it was found that M. brassicae females were significantly attracted/landed and oviposited more often on the damaged plants than on undamaged cabbage plants. Mated females oriented significantly more often to cabbage plants damaged by conspecific larvae, compared with undamaged plants. Also, these females oviposited more on damaged plants than on control plants. When the damage was increased (from 20 to 80%), the females laid more on damaged plants, but the difference with respect to undamaged plants was not significant. When chrysanthemum plants damaged by M. brassicae larvae were used, mated females did not show any difference in attraction, landing, and oviposition between damaged or control plants. The females were initially attracted/landed and oviposited significantly more often on mechanically damaged cabbage plants, compared with undamaged plants. However, when mechanically damaged tomato plants were used, the mated females did not show any difference in the 1st attraction to damaged and undamaged tomato plants. But, these same females oviposited significantly more on undamaged plants than on damaged tomato plants.