The feeding-site preferences of fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), com earworm (CEW), Helicoverpa zea (Boddie), and granulate cutworm (GCW), Agrotis subterranea (F.) were studied on excised laterals and entire plants of Florunner peanut. Sixlarval size classes, based on head-capsule widths, were distinguished for FAW and GCW, and five for CEW. FAW and CEW larvae had very similar feeding behaviors. Both species fed primarily on the terminal three leaves of peanut laterals, but this preference for young foliage declined with larval age. All FAWand CEW size classes fed on blooms, with greatest incidence (21% of feeding observations) occurring in the second through fourth size classes. Axillary-bud feeding by FAW and CEW was greatest (23 and 17% of feeding observation, respectively) in the third size class. The last two larval size classes of FAW and CEW spent 20% of feeding time on R2 pegs. GCW fed primarily on blooms through the first four size classes. Foliage feeding by GCW remained~10% of feeding observations until the fifth size class. GCW did not feed on axillary buds in whole plant studies. Peg feeding by GCW peaked in the fourth and fifth size classes (36% of feeding observations). On whole plants, each FAW consumed 4.8± 1.2 tetrafoliate leaves, severed 6.3±1.6 pegs, and damaged an additional 3.6±1.7 pegs. Each CEW consumed 4.7± 0.8 leaves, severed 7.1±1.6 pegs, and damaged 2.4±1.4 pegs. Each GCW consumed 3.9±0.5 leaves, severed 8.5±2.0 pegs, and damaged 3.5±1.3 pegs. 15,16,25,30). Several studies have referred to the feeding behavior of these noctuids. FAW larvae prefer young leaves that have been unfolded from the terminal bud for two days or less; the last two instars account for more than 80% of defoliation (2, 11). CEW larvae also prefer to feed on terminals and young peanut foliage (15, 16); over 70% of total CEW peanutfoliage consumption occurs during the last two instars (14). Pencoe and Lynch (22) found that 93% of first-instar CEW feeding occurred on terminal foliage, while 5% occurred on blooms. Older GCW larvae feed on foliage and become nocturnal feeders, hiding during the day in the soil or under debris on the soil surface (25). GCW larvae also sever leaf stems and feed on those leaves in contact with the soilduring daylight hours (25). Other than foliage-consumption studies, where only foliage was offered, little is known about the feeding behavior of these species on peanut. Our field observations indicate that canopy-inhabiting larvae feed on many plant parts other than leaves. The purpose of this studywas to determine agespecific feeding preferences of CEW, FAW, and GCWon peanut. A better understanding of the peanut-feeding behavior of these insects should be useful in the development of plant damage models and pest management practices.
Materials and MethodsAll tests were conducted on Florunner peanut. Colonies of all three species were established in August 1990, with larvae collected from peanut fields in Barnwell County, S. C. The CEW colony failed that ...
