Nymph and Adult Biology of Euschistus cornutus Dallas: a Potential Soybean Pest in the Neotropics.

Abstract

Laboratory studies with Euschistus cornutus Dallas indicated that nymphs complete development when feeding on green bean, Phaseolus vulgaris L. pod, on soybean, Glycine max (L.) Merrill pod, and on raw shelled peanut, Arachis hypogaea L., but not on fruit (berry) of privet, Ligustrum lucidum Ait. Total mortality was lower on green bean pod (45%), and higher on soybean pod and peanut raw (75 and 80%, respectively). Nymph developmental time was significantly longer for females feeding on green bean pod (37.4days) than on soybean pod (27days); a single data was observed on peanut raw (32days). Males showed no significant differences in total nymph developmental time among foods (31.3 to 33.0days). At adult emergency, fresh body weight of females (52.2 to 68.5mg) and males (61.9 to 71.3mg) did not show statistical differences among foods tested nor between genders. Survivorship of E. cornutus adult after 50days was greater on peanut raw than on green bean or soybean pod; on privet berry, the majority of males and females (>80%) were dead after 20days. The reproductive performance data was, in general, greater on peanut raw than on green bean or soybean pod; on privet fruit, no female laid eggs. Fresh body weight gain occurred on all foods, except on privet berry, on which adults lost weight over time. Records of specimens from insect collections in Brazil indicated that E. cornutus occurs in the Southeast and South regions (19° to 31° S latitude). The most common host plant is soybean, suggesting a potential pest status of this stink bug on this crop in the future.