Development and Economic-Injury Level of the Green Cloverworm on Soybean in Iowa123

摘要: Developmental and feeding trials were conducted with Plathypena scabra (F.) under 3 sets of environmental conditions. Durations the egg, larva, prepupa, pupa, adult stages 4.8, 18.7, 1.3, 9.4, 9.3 days, respectively. Significant differences found between for egg total life cycle, but no significant difference in larval stadium was indicated. Soybean leaf consumption each instar determined a photometric device. The mean soybean-foliage 19.89 in2 per larva trial 1 differed significantly from 17.06 15.55 obtained 2 3. Estimates area soybean plant made field measurements. Predictive equations to establish relationship defoliation subsequent yield loss calculated by using data previous hail-damage investigations. Theoretical economic-injury levels P. on Iowa economists' cost market data, agronomists' damage-yield this study. Calculated 5.9, 18.3, 33.5, 28.7, 40.5 larvae/row ft 1, 3, 5, 7, 9, These values suggested that most recommended chemical treatment should be revised upward.