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The competition between Telenomus podisi Ashmead and Trissolcus teretis (Johnson) parasitizing eggs of Diceraeus melacanthus (Dallas) and Euschistus heros (Fabricius) was studied in three different laboratory bioassays to gather knowledge in order to improve stink bug management and to strengthen the preservation of naturally occurring parasitoid species. The impact of parasitoid sequence and time intervals (4 to 192 h) between parasitoid species was evaluated. Competition of Te. podisi and Tr. teretis for the same host favored the parasitoid encountering the egg host first, as it usually outcompetes the second parasitoid. We conclude that it is unwarranted in a short-term goal to release both species together in augmentative biological control programs since the repeated release of Te. podisi led to higher parasitism than any other studied variation of parasitoid sequence. However, simultaneous release of multiple species could be important to help the preservation of the diversity of scelionids in the agroecosystem, a hypothesis that needs to be further investigated in future research.

Species of the genus Trissolcus are effective as egg parasitoids of Euschistus heros and can potentially be used in a multispecies pest management approach. However, in order to successfully use those biocontrol agents in the field, previous detailed knowledge about their life history are necessary. Therefore, we evaluate some biological characteristics of Trissolcus urichi on Euschistus heros and Dichelops melacanthus eggs. Three independent experiments were performed: (1) T. urichi host preference between E. heros and D. melacanthus eggs. (2) T. urichi eggs-adult period (days), number of parasitized eggs in 24 h, emergence rate (%) and sex ratio of the parasitoid in E. heros and D. melacanthus eggs. (3) Morphometric characteristics of T. urichi grown on E. heros and D. melacanthus eggs. Trissolcus urichi preferred to parasitize E. heros eggs, exhibiting a higher number of parasitized eggs, higher rate of emergence (%) and faster development, as well as producing progeny of larger size than the parasitoids emerged from eggs of D. melacanthus in relation to body length, wing length and width. Thus, it can be concluded that T. urichi had better performance on E. heros eggs, although the parasitoid had also acceptable parasitism capacity and development in D. melacanthus eggs.

This study investigates the influence of parasitoid age and egg age of the hosts Euschistus heros (Fabricius) and Dichelops melacanthus (Dallas) on parasitism of Telenomus podisi Ashmead. Six separate bioassays were conducted: parasitism on eggs of E. heros (bioassay 1) and D. melacanthus (bioassay 2) by T. podisi females of different age (1, 5, and 10 days old); parasitism by T. podisi on eggs of different age (1, 2, 3, 4, and 5 days of embryonic development) of the hosts E. heros (bioassay 3) and D. melacanthus (bioassay 4); preference of T. podisi females for eggs at different embryonic developmental stages (eggs of 1, 2, 3, 4, and 5 days) of the hosts E. heros (bioassay 5) and D. melacanthus (bioassay 6). The age of T. podisi females and their hosts affected parasitism on both E. heros and D. melacanthus eggs. Overall, the parasitism rate was higher in older than younger parasitoids, independent of the tested host species, and host eggs between 1 and 3 days old were similarly parasitized. Thus, in T. podisi mass rearing facilities, it is recommended to use older adults (5 to 10 days old) as mother wasps to increase parasitism on the offered eggs. In addition, when hosts are completely absent in the field, or climatic conditions are unfavorable for release, mass-reared adults can be kept in the laboratory (25°C) for up to 10 days for later release in the field without any impairment of their subsequent parasitism performance.

Successful parasitoid rearing is crucial for augmentative biological control. A low temperature preservation protocol allowing the availability of host and parasitoid year-round was evaluated in this study in four bioassays: (1) host eggs [Euschistus heros (Fabricius)] stored at - 196, - 80, and - 20°C for up to 70 days prior to exposure to Telenomus podisi Ashmead parasitism; (2) Euschistus heros eggs removed from storage at - 196°C after 70 days and kept at 5°C for up to 9 days prior to exposure to T. podisi parasitism; (3) Telenomus podisi adult emergence of insects stored as pupae at 5°C; and (4) fitness of adults of T. podisi stored at 5°C. Higher parasitism was observed in parasitoids reared on E. heros eggs stored at - 196 and - 80°C. Host eggs removed from - 196°C and stored at 5°C for up to 6 days did not impact T. podisi parasitism and development. Storage of T. podisi pupae for more than 7 days negatively affected parasitoid biology. Storing T. podisi adults at 5°C for up to 6 days does not alter the biological parameters of the parasitoid. Thus, parasitoids can be stored as pupae or adults as well as its host E. heros eggs. Our findings can be applied to improve the feasibility of year-round insect production.

Records in the literature with regard to the influence of freezing of pentatomid eggs on parasitism by microhymenopterans are scarce. In this research, we compared the storage of Euschistus heros (Fabricius) (Hemiptera: Pentatomidae) eggs in liquid nitrogen for different periods with the objective of optimizing the multiplication of Telenomus podisi Ashmead (Hymenoptera: Platygastridae) in the laboratory. Fresh eggs of E. heros were exposed (S3, S6) or not (NS3, NS6) to UV light for 30 min and stored in 1.5-mL plastic vials in liquid nitrogen either for 3 (S3, NS3) or 6 months (S6, NS6), and egg suitability to parasitoid development was compared to control eggs exposed (SC) or not (NSC) to UV treatment. Global data analysis showed that E. heros eggs stored in liquid nitrogen with or without UV treatment, for 3 or 6 months, were suitable for T. podisi parasitization.

We report the first record of the stink bug Edessa meditabunda (F.) on lettuce Lactuca sativa in the organic vegetable garden "Cheiro Verde" in Tangará da Serra, State of Mato Grosso, Brazil (14°37'13″ S, 57°28'46″ W). During September, October, and November 2009, we collected 1,099 adults, 43 nymphs, and 29 egg masses. Feeding by this stink bug possibly caused early bolting.