Primeiro registro de parasitoides de ovos de Oebalus poecilus (Dallas, 1851) (Hemiptera: Pentatomidae) em arroz no Maranhão, Brasil

Abstract

Biological conlrol using natural cncmics such us cgg pnrasitoids can he an allernalíve to rcgulate pests as it rcduccs llicir populational dcnsity and, conscquently, thc damagc to host plants. Thcrcfore, thc objectivc of thc prcsent study was to Icarn about thc spccies of cgg parasitoids of Oebalus poecilus (Dallas, 1851) (Hemiplcra: Pentatomidac) on ricc in thc State of Maranhão, Brazil. Thc experiment was carrícd out in an upland ricc crop in onc of Cristina Alves Scttlcment units - April 17 Community, locatcd in thc city of Itapccuru Mirim, Maranhão, Brazil. To survey thc egg parasitoids of O. poecilus, visual inspections were made in rice leaves, stalks and panicles at the carly reproduetive stage (milky grains). The egg masses collected were individually transferred to lidded 100 mL plastic cups with filter paper slightly moistened with distilled Avater. Subsequently, the collected material was placed in a polystyrcne box and sent to the Entomology Laboratory of the Center of Agrarian Sciences, State University of Maranhão (UEMA), Brazil, for daily observations of parasitoid and/or nymph emergence rates. Then the emerged parasitoids were placed in 1.5 mL flasks containing 70% alcohol and sent to the Biological Institute in Campinas, State of São Paulo, for identification. Considering 19 egg masses (298 eggs) of O. poecilus collected, the natural parasitism rate was 11.4% (6.71% and 4.69% for emerged and non-emerged eggs, respectively). The identified species were: one specimen of Trissolcus urichi (Crawford, 1913) and 19 specimens of Telenomus podisi Ashmead, 1893 (Hymenoptera: Scelionidae). This was the flrst report of T. urichi and T. podisi parasitizing eggs of O. poecilus in the State of Maranhão, Brazil, under field conditions, with a natural parasitism rate of 11.4%