Location of Beet Armyworm (Lepidoptera: Noctuidae) Egg Mass Deposition within Canopies of Cotton and Pigweed

Beet Armyworm (Lepidoptera: Noctuidae) Host Plant Preferences for Oviposition

“…Host-dependent variation of egg mass size or clutch size has been reported in other insects (Van Leerdam et al 1984, Grant andLangevin 1995). Sappington et al (2001) reported 29% fewer eggs per egg mass oviposited by beet armyworm on cotton compared with that on pigweed in Þeld cage tests, whereas the results reported herein revealed no differences between these two hosts in isolated leaf and potted-plant experiments. In greenhouse studies, Smits et al (1986) found that variation in beet armyworm egg mass size did not vary among hosts that included chrysanthemum, tomato, gerbera, and geranium, but that younger chrysanthemums received more eggs than older plants.…”

“…In parallel studies, we found that indices of beet armyworm developmental efÞciency from larva to adult depended on host plant, also in the same hierarchical order. For example, development on pigweed from Þrst instar to pupa was several days faster, and required less gram-intake of leaf tissue than development on cabbage (Greenberg et al 2001). Thus, it appears that the host plant oviposition preference hierarchy of beet armyworm females corresponds to nutritive value of the potential hosts, and that egg mass size can be modiÞed to reßect the perceived suitability of a host that a female has selected for oviposition.…”

Identification and Diel Activity Patterns of Predators AttackingHelicoverpa zea(Lepidoptera: Noctuidae) Eggs in Soybean and Sweet Corn

“…Egg groups were attached to the top of a soybean leaf Ϸ45Ð55 cm above the ground (Ϸ55Ð70% of plant height) or to one of the small leaves (husk terminals) directly adjacent the silks on the primary ear of a corn plant. Pest of Þeld crops such as soybean often deposit their eggs on the foliage of the middle to upper parts of the plant (Terry et al 1987, Sappington et al 2001; R.S.P., unpublished data) although often on the undersides of leaves. Placing the eggs on the top of leaves was done to facilitate observation.…”