Flutuação populacional de Euschistus heros (Fabricius, 1789) (Hemiptera: Pentatomidae) e parasitismo de Telenomus podisi (Ashmead, 1893) (Hymenoptera: Platygastridae) após liberações em cultivo orgânico de soja

Abstract

In soy reproductive period the brown stink bug Euschistus heros Fabricius 1789 (Hemipetera: Pentatomidae) stands out as the mean insect pest, damaging the plant and compromising its development. In organic systems the massive release of egg parasitoid can be made to control this pest, as the Telenomus podisi Ashmead 1893 (Hymenoptera: Platygastridae) Accordingly, the aim of this work was to evaluate the E. heros population fluctuation and the T. podisi parasitism rates released to the field, over E. heros eggs. The study was made in the 2018/2019 summer harvest, in organic farm, located in Palotina-PR. The nymph population fluctuation < 0,3 cm and E. heros adults was sampling by beating cloth method after the V7 to R6 stages, on weekly sampling, in eight randon points/plot. To T. podisi parasitism evaluation over E. heros eggs the treatments consisted of areas with parasitoid release and areas without parasitoid release. The release of parasitoids (T. podisi parasitized 10 thousand E. heros eggs/ha) occurred in the 80º day after the plantation. In the 3º and 5º day after the release the areas were inspected 2 hours/plot and the laying of E. heros eggs was collected, identified and sent to the lab to monitor the emergence of T. podisi. In both areas (with and without T.podisi release), E. heros population growth was observed, from R5.1, with an average peak of 8.1 and 6.8 nymphs <0.3 cm per beat cloth in R6, respectively in areas without and with the release of T. podisi. Were no significant difference in T. podisi parasitism rates over E. heros eggs collected in the 3º day after release. However, in the 5º day, in the areas with the T. podisi release a higher parasitism rate was observed (63,7%) then in the without parasitoid release (34,9%). The T. podisi use can become an important tool to E. heros control in organic soy systems, although is important that other new studies be done willing to test diferente periods and release methods.