Optimizing Mass Rearing of the Egg Parasitoid, Telenomus podisi, for Control of the Brown Stink Bug, Euschistus heros

Abstract

The parasitoid Telenomus podisi Ashmead, 1893 is used in biological control programs in Brazil against eggs of Euschistus heros (Fabricius, 1798), a key pest of soybean, Glycine max (L.) Merr. To optimize the mass production of parasitoids, artificial diets and storage of host eggs at low temperatures have been developed; however, direct comparisons of the effects of these conditions have not occurred. We assessed a double factorial arrangement composed of six treatments (fresh or cryopreserved E. heros eggs from adults fed on natural or two artificial diets). We evaluated the biological characteristics and parasitism capacity of T. podisi produced from these treatments across seven temperatures. The thermal range between 21 and 30 °C resulted in satisfactory daily parasitism in all treatments tested, with an inverse relationship between temperature and female survival. The best parasitoid biological parameters were found between 21 and 27 °C, where all tested diets supported T. podisi development, with the best results from artificial diets. Fresh eggs and those frozen in liquid nitrogen and stored at −196 °C until use supported parasitoid development. These results suggest that the best method to mass rear T. podisi is to use artificial diets to rear E. heros and store eggs until needed, and then rear parasitoids at 24 °C.

Biology of Spodoptera Eridania (Cramer, 1792) (Lepidoptera: Noctuidae) at Different Temperatures and Diet Sources

“…Furthermore, it was also found that females fed strawberry leaflets at a temperature of 31 ºC did not oviposit. These results confirm information from other authors that this interaction can interfere with the survival and reproduction of insects (Schowalter 2016a;Schowalter 2016b;Paes et al 2018, Lacerda et al 2019Barret et al 2023;Parra et al 2023).…”

“…The interference of the biotic factor may be related to insects feeding on plants with low nutritional quality, which can affect their biological, physiological, and behavioral characteristics, through the reduction of size, weight, survival, the intensity of consumption by larvae, longevity, and potential reproductive, etc. (Cabezas et al 2013;Gomes et al 2017;Schowalter 2016b;Silva et al 2017;Silva et al 2019;Zamora Belli et al 2020;Páez Jerez et al 2022;Parra et al 2023).…”

Optimizing the Release Pattern of Telenomus podisi for Effective Biological Control of Euschistus heros in Soybean

“…The use of cryopreserved eggs as sentinels in our experiments may have influenced the relatively low parasitism rates observed [ 31 ]. Although E. heros cryopreserved eggs are suitable for T. podisi laboratory mass rearing [ 8 , 9 , 32 ], the use of frozen eggs can slightly reduce the parasitism rate (%) by T. podisi [ 7 ]. Additionally, the use of poles with attached cryopreserved eggs did not present the same chemical compounds emitted by soybean plants during stink bug feeding prior to mating and oviposition [ 33 ].…”

“…The number of eggs offered (about 1890 eggs per plot), the time allowed for parasitism (24 h) and the use of cryopreserved eggs as sentinels might also explain the low parasitism rate observed. The number of eggs and distance might exceed T. podisi ’s parasitism capacity in 24 h. Although in applied inundative biological control programs, the parasitism capacity holds greater significance than the lifespan of females in the field [ 8 ], T. podisi females might have needed more than 24 h for the pre-reproductive period to reach its full parasitism capacity in the field [ 34 ]. Bueno et al [ 2 ] reported a 70% parasitism rate in soybean fields after T. podisi release; however, this was after three parasitoid releases and over a period of 27 days.…”

“…One of the most-studied egg parasitoids, Telenomus podisi Ashmead, 1893 (Hymenoptera: Scelionidae), is recognized as an effective natural enemy for the key stink bug pests that attack soybean crops [3]. Following the commercial release of T. podisi Insects 2024, 15, 192 2 of 12 in 2019 in Brazil [4], more robust programs and studies have been conducted to improve the use of this biological control agent in combatting stink bug pests of soybeans [5][6][7][8].…”