The objective of this work was to evaluate the damages caused by stink bug populations of Euschistus heros (F.) and Piezodorus guildinii (West.) to soybean crop on november/december, prior to pod set. Greenhouse and field experiments were carried out comparing infestations at vegetative-flowering and pod development stages. Soybean plants at vegetative and flowering growth stages, even under severe bugs infestation (8 per plant) did not show significant yield reduction. Seed quality, was similar among population levels and bug species. At R4 stage, the number of seedless pods increased proportionally to the number of bugs per plant. In field experiment, yield and seed quality of soybean plants infested with up to four E. heros or P. guildinii adults per meter, at the end of the vegetative-flowering stage, were similar to bug-free plants. The number of bug-punctured and inviable seeds increased and the average yield decreased with the increase of population levels of both bug species, at the pod filling stage (R5-R6) infestation. In relation to the soybean quality, the damage caused by P. guildinii was twice bigger than that caused by the brown stink bug. Infestations of these stink bugs on the vegetative-flowering stage do not cause reduction on yield and quality of soybean seeds.
Glycine max; Euschistus heros; Piezodorus guildinii; Pentatomidae; integrated management
