Parasitism of Helicoverpa armigera pupae (Lepidoptera: Noctuidae) by Tetrastichus howardi and Trichospilus diatraeae (Hymenoptera: Eulophidae)

Abstract

Helicoverpa armigera is a pest that was recently detected in Brazil, which causes significant losses in various crops in different regions of the country. Biological control has been reported to offer a promising alternative in the management of this pest. Thus, this study evaluated the ability of the parasitoids Tetrastichus howardi and Trichospilus diatraeae to parasitize pupae of H. armigera in the laboratory. H. armigera pupae were individually exposed to 15 female Trichospilus diatraeae or 15 female Tetrastichus howardi for 24 h. The pupae remained under observation until the emergence of parasitoids. Parasitism by both parasitoids was observed in 100% of the pupae. Further, 100% of Tetrastichus howardi and 90% of Trichospilus diatraeae emerged. The life cycle of Tetrastichus howardi parasitizing pupae of H. armigera was 15 ± 0.0 days, while that of Trichospilus diatraeae was 15.90 ± 0.10 days. The numbers of offspring from Tetrastichus howardi and Trichospilus diatraeae were 669.3 ± 33.47 and 816.11 ± 89.22 per pupae, with a sex ratio of 0.91 ± 0.01 and 0.94 ± 0.01, respectively. Tetrastichus howardi and Trichospilus diatraeae were shown to successfully parasitize H. armigera pupae in laboratory conditions, suggesting that this host could be used for rearing both parasitoids. However, further detailed studies of the host-parasitoid relationship are needed to assess the feasibility of including these parasitoids in integrated management programs of H. armigera. Key words: Biological control, insect pests, parasitoid ResumoHelicoverpa armigera é uma praga recentemente identificada no Brasil ocasionando perdas significativas em várias culturas em várias regiões do país. O controle biológico tem sido relatado como uma das alternativas promissoras para o manejo desta praga. O objetivo deste trabalho foi avaliar o parasitismo de pupas de H. armigera pelos parasitoides Tetrastichus howardi e Trichospilus diatraeae, em laboratório. Pupas de H. armigera foram individualizadas e expostas ao parasitismo por 15 fêmeas de Trichospilus diatraeae ou por 15 fêmeas de Tetrastichus howardi, durante 24 h. Após este período, as pupas permaneceram em observação até a emergência dos parasitoides. As porcentagens de parasitismo de Tetrastichus howardi e Trichospilus diatraeae foram de 100%. Em relação à emergência, 1 Pesquisador, Dr., Embrapa Agropecuária Oeste, Dourados, MS, Brasil.

Trichospilus diatraeae (Hymenoptera: Eulophidae): development and reproduction in Lepidoptera palm oil pests

“…The similar parasitism of B. sophorae and O. invirae pupae by T. diatraeae confirms the generalist habit of this parasitoid, as reported with Anticarsia gemmatalis Hübner, Heliothis virescens (Fabricius), Spodoptera frugiperda (Smith) (Noctuidae) and Diatraea saccharalis (Fabricius) (Pyralidae) (Paron and Berti-Filho, 2000), Thyrinteina arnobia (Stoll) (Geometridae) Tenebrio molitor L. (Tenebrionidae) (Favero, 2009) and Helicoverpa armigera pupae (Lepidoptera: Noctuidae) (Oliveira et al, 2016) pupae. Moreover, the similar percentage of emergence from O. invirae and B. sophorae pupae compared to T. diatraeae confirms the quality and/or nutritional values of these host to the parasitoid, because these factors can affect the onset and development of natural enemies (Brodeur and Boivin, 2004;Zanuncio et al, 2008).…”

“…The pupal parasitoid Trichospilus diatraeae Cherian & Margabandhu (Hymenoptera: Eulophidae) of Asian origin is gregarious, with polyphagous habit but with high prevalence in lepidopteran with its record in 1942 in the sugarcane borers, Diatraea venosata Walker (Lepidoptera: Pyralidae) (Bennett et al, 1987). This parasitoid has been studied for the biological control of pests in cucurbitaceous, eucalyptus, corn, pasture, soybean and sugar cane (Oliveira et al, 2016;Silva et al, 2015;Zaché et al, 2010).…”

Multiple incursion pathways forHelicoverpa armigerain Brazil show its genetic diversity spreading in a connected world

“…In Brazil where the incursion of H. armigera was first reported, stochastic lineage sorting of founding populations (i.e., hypothesis I) could lead to the observed heterogeneous haplotype distribution patterns. This could involve factors such as lower population density and variability at population introduction phase and/or the lag-phase, high variability of reproductive success rates (e.g., see Gaither et al [63]), variable adaptation success rates (e.g., differential response to attacks by parasitoids and/or predation rates [64]), susceptibility to viral/bacterial/fungal pathogen attacks, climatic stress, etc. to the novel New World environments at the early incursion stages.…”

Reproduction of Trichospilus diatraeae (Hymenoptera: Eulophidae) with Different Densities and Parasitism Periods in Anticarsia gemmatalis (Lepidoptera: Noctuidae) Pupae

“…A higher rate of parasitism occurs in the proportion of three to five females of N. vitripennis per pupa of C. megacephala (MELLO et al 2009). For females of T. howardi and T. diatraeae, 24 hours are sufficient to reach 100% parasitism in Helicoverpa armigera (Hubner, 1808) (Lepidoptera: Noctuidae) pupae (OLIVEIRA et al 2016). The density of six A. gemmatalis pupae with ten T. diatraeae females shows that these characteristics are the most appropriate to mass production of this parasitoid, as well as for obtaining more females (sex ratio).…”

“…The use of parasitoids for biological control programs depends on finding adequate alternative hosts for mass production (PEREIRA et al 2009;OLIVEIRA et al 2016). The selection of the host is crucial in the mass creation of parasitoids (MAGRO & PARRA 2001;RAMALHO & DIAS 2003), since its physical and chemical characteristics can affect the acceptance and adaptation of the species and/or lineages, interfering in this way in the biological characteristics, impairing the quality of the parasitoid produced and its performance in field (BIGLER 1994;MONJE et al 1999;VIEIRA et al 2017).…”