Impactos na fisiologia das plantas, bioecologia e resistência de pentatomideos à inseticidas e seletividade a Telenomus podisi (Ashmead, 1893) (Hymenoptera: Scelionidae)

Abstract

Euschistus heros (Fabricius, 1794) is an economically important insect pest in soybean Glycine max L. and Diceraeus melacanthus (Dallas, 1851) (Hemiptera: Pentatomidae) for corn Zea mays L., with little incidence in soybean crops. Therefore, it is necessary to evaluate the adaptation in the biology and behavior of these species in these crops to estimate the damage and enable control alternatives, avoiding negative interference with natural enemies. Given this, the objectives were: To study the biology of D. melacanthus in soybean, corn, and artificial diet; to evaluate the efficiency of insecticides on E. heros; to determine the effects of the products on Telenomus podisi (Ashmead, 1893) (Hymenoptera: Scelionidae); and to evaluate photosynthetic parameters in soybean (R4) under attack by D. melacanthus. The experiments were conducted under controlled conditions at the Applied Entomology Laboratory (LEA-UFGD) - Dourados-MS. Biological parameters of D. melacanthus were determined on soybean, corn (V3-V4), and artificial diet, evaluating survival, longevity, and fecundity. The efficiency of five insecticidal molecules used on soybean and corn was also evaluated: Thiamethoxam + Lambda- Cyhalothrin; Bifenthrin + Carbosulfan; Acephate + Bifenthrin; Acetamiprid + Bifenthrin; and Etiprole, in dose-response and survival curve assays on E. heros, as well as the effect of these molecules on parasitism and emergence of T. podisi in pre-parasitism assays. Furthermore, the effect of D. melacanthus attack on different soybean cultivars at the reproductive stage (R4) was evaluated, focusing on photosynthesis, transpiration rate, stomatal conductance, Soil Plant Analysis Development (SPAD) index, and chlorophyll content. Survival analysis of the female green-bellied beetles showed significant differences between treatments, with the artificial diet and the Bt soybean and conventional corn treatments resulting in the highest probability of survival over time. Regarding insecticidal molecules, Acephate + Bifenthrin caused the greatest negative effect on T. podisi, while Etiprole had the least effect. As a result, it was observed that D. melacanthus attack on soybeans significantly reduced the photosynthetic rate, SPAD index, and chlorophyll content, and increased the transpiration rate and stomatal conductance.