Trichogramma parasitoids for control of Lepidopteran borers in Taiwan: species, life‐history traits and Wolbachia infections

Abstract

Trichogramma, polyphagous endoparasitoids of lepidopteran eggs, are used against a variety of crop pests throughout the world including those of sugar cane and corn in south-eastern Asia. Their ability to be easily and economically reared on factitious hosts and their wide host range have contributed to their widespread use in pest control. The overall aim of this study was to select strains for eventual release in crop areas for control of lepidopteran borer pests of sugar cane and corn. To this end, we identified common Trichogramma species emerging from corn borer egg masses throughout south-western Taiwan, compared their life-history characteristics, assessed their thermal limits and identified the Wolbachia infection status of collected Trichogramma parasitoids. Trichogramma ostriniae was the most commonly collected species on corn, with occasional detection of T. chilonis and an unidentified species designated as T. sp. y. Although the sex ratio varied widely between sites, Wolbachia infection was detected only at a single site in one species (T. ostriniae). Wolbachia-infected T. ostriniae were tolerant to high temperature stress. Trichogramma chilonis had lowest fecundity of the three species tested, and a Wolbachia-infected T. ostriniae strain had lower fecundity than an uninfected strain. Given the limited availability of distribution and historical data for Trichogramma species in Taiwan, the current study provides a baseline for future work and also highlights the importance of accurately identifying species when establishing colonies of natural enemies for biocontrol.

Assessing the current and future biological control potential of Trichogramma ostriniae on its hosts Ostrinia furnacalis and Ostrinia nubilalis

“…Meta‐analyses have suggested for competing natural enemy species that antagonism may result in effects on the target being less than additive, and this deleterious outcome is most obvious when the same life stage of a host is attacked . Therefore, any inference regarding areas suitable for T. ostriniae ought to be made with caution and requires empirical studies that include molecular identification of potential competing Trichogramma species that might have been incorrectly identified …”

“…15 Therefore, any inference regarding areas suitable for T. ostriniae ought to be made with caution and requires empirical studies that include molecular identification of potential competing Trichogramma species that might have been incorrectly identified. 23,68 In terms of biological control, there are perhaps implications for areas with GI differences that favour the parasitoid over the host (Fig. 6a,c).…”

“…The geographical range of ACB extends from eastern and southeastern Asia, through to the western Pacific islands . The endemic egg parasitoid, Trichogramma ostriniae Pang & Chen (1974), is the predominant species parasitizing ACB across the native range, which consists of most of the corn‐cropping regions of southeastern Asia . In China, Trichogramma biocontrol of ACB has been conducted since the early 1950s; today nearly four million hectares of cornfields are treated with T. ostriniae and other Trichogramma species across southeastern Asia annually .…”

“…22 The endemic egg parasitoid, Trichogramma ostriniae Pang & Chen (1974), is the predominant species parasitizing ACB across the native range, which consists of most of the corn-cropping regions of southeastern Asia. 21,23 In China, Trichogramma biocontrol of ACB has been conducted since the early 1950s; today nearly four million hectares of cornfields are treated with T. ostriniae and other Trichogramma species across southeastern Asia annually. 21 Surveys of both T. ostriniae and ACB in the native range provide an opportunity to model the current distribution and investigate potential distributions of the host and this parasitoid under climate change scenarios across southeastern Asia.…”

Mudanças genéticas e fenotípicas associadas à criação de <i>Trichogramma galloi </i>Zucchi, 1988 (Hymenoptera: Trichogrammatidae) nos hospedeiros natural e alternativo e os efeitos da hibridização intraespecífica no seu <i>fitness</i>

“…Liberações de Trichogramma têm sido realizadas para o controle de pragas em uma grande diversidade de culturas, incluindo culturas economicamente importantes como, soja, milho, tomateiro, cana-de-açúcar, entre outras (HASSAN, 1993;LI, 1994;PARRA;ZUCCHI, 2004;WANG et al, 2014;WU;HOFFMANN;THOMSON, 2015;PARRA et al, 2015). No Brasil, as liberações de parasitoides têm aumentado de maneira significativa, principalmente devido à utilização do parasitoide de ovos Trichogramma galloi Zucchi, 1988 (Hymenoptera: Trichogrammatidae) para o controle da broca da cana-de-açúcar, Diatraea saccharalis (Lepidoptera: Crambidae) (PARRA; ZUCCHI, 2004; PARRA; BOTELHO; PINTO, 2010).…”