Parasitismo e desenvolvimento de Ooencyrtus submetallicus (Hym.: Encyrtidae) e Telenomus podisi (Hym.: Platygastridae) em ovos de Euschistus heros (Hem.: Pentatomidae)

Abstract

The successful use of parasitoids in biological control programs depends on knowledge of biological characteristics such as the thermal demand on the target host. This work evaluated the biological characteristics of Ooencyrtus submetallicus (Howard, 1897) (Hymenoptera: Encyrtidae) and Telenomus podisi (Ashmead, 1893) (Hymenoptera: Platygastridae) parasitizing eggs of Euschistus heros (Fabricius, 1798) under conditions: The laboratory test, under different temperature conditions, estimated the number of generations for seven soybean producing locations in Brazil and the fertility life table parameters. The experiments were carried out at the Laboratory for Biological Control of Insects (LECOBIOL) of the Federal University of Grande Dourados (UFGD), in Dourados, Mato Grosso do Sul. A comparative biology study was carried out, where the percentage of parasitism and emergence, life cycle duration (egg-adult) and longevity were similar between O. submetallicus and T. podisi. The sex ratio and the number of emerged individuals per egg were higher for O. submetallicus in all regions tested. In the study of thermal requirements, temperatures of 16, 19, 22, 25, 28, 31 or 33 °C were tested. Ooencyrtus submetallicus and T. podisi developed at temperatures between 16 and 31 °C. The base temperature (Tb) for O. submetallicus and T. podisi was 9.3 ° and 6.7 °C, while the thermal constant (K) was 336, 9 and 272.7 degree days. The estimated mean number of annual generations of both parasitoids were higher than the host. Ooencyrtus submetallicus and T. podisi have the same ability to parasitize and develop in E. heros eggs under the conditions studied. Both parasitoids exhibited satisfactory development and parasitism at temperatures between 19 ° and 31 ° C. The development of both parasitoids was faster than their host, and the number of generations was higher for the seven locations studied. The study of the fertility life table was carried out with daily offering of eggs for the parasitism until the death of all females. Life cycle duration (egg-adult) was 17.5 days for O. submetallicus and T. podisi. The longevity of females of O. submetallicus and T. podisi was estimated at 18.1±0.78 and 21.1±0.85 days, with an innate capacity to increase in number of 0.16 and 0.18; net reproduction rate of 58.30 and 52.34; finite ratio of increase of 1.18 and 1.20; mean time between generations of 24.47 and 21.24 days and population doubling time of 4.17 and 3.69 weeks. It was found that O. submetallicus has a reproductive performance similar to that of T. podisi. Indicating that both parasitoids have potential as biological agents in the control of E. heros.