Abstract
Cultivars 'BSR 101' (Maturity Group II) and 'Cumberland' (Maturity Group III) of soybean were planted in three environments in Puerto Rico in 1981 and 1982 for a study of whether the damage caused by pests is lessened by seeds being harvested at different stages of development in tropical field conditions. Harvest of seeds began 24 days after flowering (DAF) and continued at weekly intervals until plants reached maturity at 59 DAF. Pest symptoms were identified, and their incidence was recorded on the basis of two 50-seed samples for each cultivar, harvest date, and environment. Immature soybean seeds harvested as early as 24 DAF had symptoms of purple seed stain [Cercospora kikuchii (T. Matsu. & Tomoyasu) Gardner], downy mildew [Peronospora manshurica (Naum.) Syd. ex Gaum.], anthracnose [Colletotrichum dematium (Pers. ex Fr.) Grove var. truncatum (Schw.) Arx.], and pod blight [Phomopsis spp.), insect damage from lima bean pod borer [Etiella zinckenella (Treitschlce)], and southern green stink bug [Nezara viridula (L)]. Maximum levels of pest damage were observed on seed harvested 38 DAF or later, depending on the organism and the environment. Results indicate that the harvest of immature soybean seeds at 31 DAF could reduce the incidence of pest damage identified in this study.