Feeding duration and damage of stink bugs (Heteroptera: Pentatomidae) to soybean seed and salivary enzyme activity

Laboratory studies were conducted to compare duration of feeding and superficial and in-depth damage to soybean [Glycine max (L.) Merrill] seeds (mature and water imbibed) by selected species of pentatomids, major pests of field crops in the neotropics such as, the southern green stink bug, Nezara viridula (L.), the neotropical brown stink bug, Euschistus heros (F.), the red-banded stink bug, Piezodorus guildinii (Westwood), and the green belly stink bug, Dichelops melacanthus (Dallas) (Heteroptera: Pentatomidae). Results indicated that feeding time was significantly longer for N. viridula (ca. 133 min) compared to E. heros and D. melacanthus (ca. 70 min); P. guildinii fed for about 103 min, which did not differ significantly from N. viridula. There was a positive correlation between feeding time and resulting damage to seeds for E. heros, N. viridula and P. guildinii, but not for D. melacanthus. The deepest seed damage (2.0 mm) occurred when P. guildinii penetrated the seeds while the shallowest seed damage (0.5 mm) was observed for D. melacanthus. The depth of seed damage for E. heros and N. viridula (0.8 and 1.2 mm, respectively) was intermediate. Feeding damage to the seed cotyledons caused cell disruption and protein bodies destruction, particularly when N. viridula and P. guildinii fed on seeds; they showed 5X more salivary enzyme (cysteine protease) activity than the remaining species.