•Augmentative biological control of Halyomorpha halys was tested in Northern Italy.•1000 Anastatus bifasciatus/ha (325,000 in total) were released in 11 sites.•Releases improved discovery efficiency ...and parasitism rate by A. bifasciatus.•Trissolcus mitsukurii was not affected by the releases of A. bifasciatus.
We report the first large-scale augmentative biological control project carried out in Europe against Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) using the native egg parasitoid Anastatus bifasciatus (Geoffroy) (Hymenoptera: Eupelmidae). During summer 2020, a total of 325,000 adults of A. bifasciatus were released at a rate of 1000 individuals/ha of orchard in 11 sites in Trentino-Alto Adige (Northern Italy). Parasitism parameters were compared between release and control (no release) sites, in which at least three egg masses naturally laid by H. halys were collected (for a total of 262 egg masses). Anastatus bifasciatus and Trissolcus mitsukurii (Ashmead) (Hymenoptera: Scelionidae) were the dominant parasitoids, but parasitism by both species fluctuated widely among sites. At release sites, A. bifasciatus showed a significantly higher discovery efficiency (31.4%) and parasitism rate (16.7%) of H. halys egg masses than at control sites (1.7% and 1.2%, respectively). Parasitism by A. bifasciatus was not dependent on egg mass abundance at release sites, but at control sites a host density-dependent response was revealed by a positive relationship between parasitism and number of H. halys egg masses. On the other hand, parasitism by the adventive T. mitsukurii was not affected by either the releases of A. bifasciatus or by the abundance of H. halys egg masses per site. In conclusion, augmentative releases of A. bifasciatus contributed to increasing its parasitization of H. halys, without causing any negative effects on parasitization by naturally occurring species.
Adventive populations of Trissolcus japonicus (Ashmead), an egg parasitoid of the invasive agricultural pest, brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), have been ...detected in the United States since 2014. Given its importance as an H. halys biocontrol agent, efforts to redistribute T. japonicus began within some US states. Our surveillance for T. japonicus in northwestern Virginia in 2016–2017 yielded annual detections only in 1 county. Thus, to promote its broader establishment, releases of H. halys egg masses parasitized by T. japonicus from Virginia occurred in 2018 (2 releases) and 2020 (1 release) at 9 sites throughout Virginia's tree fruit production regions. Monitoring of T. japonicus and H. halys, using yellow sticky cards deployed in H. halys host trees and pheromone-baited sticky traps, respectively, was conducted from 2018 to 2022. Annual captures of H. halys adults and nymphs appeared to reflect adequate populations to support T. japonicus establishment across most or all sites. Prerelease monitoring yielded a single T. japonicus at 1 site. By 2022, T. japonicus was detected at or near 7 of the remaining 8 release sites, with first detections varying between 1 and 2 yr from the releases in 2018 and 2020. Captures at most sites were very low, but establishment at several locations was indicated by detections in 2–4 seasons. In 2022, T. japonicus surveillance at 11 additional sites in northwestern Virginia yielded detections at all locations, including those at which it had not been detected in 2016–2017, providing evidence for its range expansion.
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•Trissolcus japonicus developed much faster than Anastatus japonicus in Halyomorpha halys eggs.•T. japonicus outcompeted A. japonicus when the time lag between the attacks was ≤ 1 ...day.•A. japonicus outcompeted T. japonicus when the time lag between the attacks was 2 to 5 d.•The combined release of the two parasitoids did not show any advantage compared to a single release.
Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae) and Anastatus japonicus Ashmead (Hymenoptera: Eupelmidae) are the most important egg parasitoids of Halyomorpha halys Stål (Hemiptera: Pentatomidae) in northern China. In this study, we assessed the fitness of these two parasitoid species at different temperatures. We examined the intrinsic competition of these parasitoids inside host eggs by providing each parasitoid species with H. halys egg masses previously parasitized by the other species, at different time intervals between attacks. We also investigated their intraguild competition for H. halys eggs by releasing a single species (one female T. japonicus or five female A. japonicus per cage) or both parasitoid species (one female T. japonicus and five female A. japonicus per cage) simultaneously in exclusion cages stocked with three host egg masses per cage in a kiwifruit orchard. Our results showed that the developmental time from eggs to adults of both parasitoids decreased with increased temperatures, between 15 °C and 30 °C, and T. japonicus developed much faster than A. japonicus during the immature stages in host eggs. Both T. japonicus and A. japonicus were able to parasitize a host already parasitized by the other parasitoid, and sex ratios of their offspring from multi-parasitized hosts were male-biased for both parasitoids. Inside host eggs, T. japonicus outcompeted A. japonicus when the time lags between the first and second attacks were less than or equal to 1 day, regardless of the order of attack by the two parasitoids, whereas A. japonicus began to dominate when the time lag was 2 to 5 d. The host location, exploitation and impact indexes of the two parasitoids were influenced by their exploitation modes and/or releases in the exclusion cage tests in the field. However, regardless of single or simultaneous release, the parasitism rates of the two parasitoids were not so much affected. We concluded that the combined release of T. japonicus and A. japonicus at the given parasitoid densities did not show any advantage compared to the single release of either species. The two parasitoids employed different reproductive strategies contributing to the outcome of their interspecific competition, which should be considered in any future biological control program for the sustainable management of H. halys.
Stink bug (Hemiptera: Pentatomidae) development typically requires feeding on a diversity of plant species and various plant tissues. During feeding, stink bugs discharge salivary enzymes with roles ...in extraoral digestion and countering plant defense responses. Although previous research has described digestive salivary proteins from stink bugs, less is known of the salivary proteins involved in the suppression of plant defenses. We sequenced the transcriptomes of salivary glands dissected from five stink bug species collected from non-crop habitats in Washington: Halyomorpha halys (Stål), Nezara viridula L., Euschistus conspersus (Uhler), Thyanta pallidovirens (Stål), and Chlorochroa ligata (Say). We identified a total of 677 candidate secreted proteins from the salivary glands of the five species. Based on work from other insects, many of the proteins have potential functions in the suppression of plant defense signaling and deactivation of plant defense molecules. We also identified salivary proteins with potential roles in the extraoral digestion of plant tissues, protection from entomopathogens, and deposition of salivary sheaths. This report provides a curation of putative salivary effector genes for further functional analysis.
Polyphagous phytophagous organisms that shelter in man-made objects have a higher chance of becoming invasive fast-spreading pests, going undetected during phytosanitary checks and travelling with ...any type of goods. However, if the same organisms are also a household nuisance, they could be used in crowdsourcing surveys aimed at their early detection and to track their spread in real time. By participating in these surveys, people can be educated on the destructive potential of invasive species and on sustainable management options. However, in order to obtain good-quality data, useful to plant protection stakeholders, a one-to-one approach with people is crucial. The case study is the Italian invasion of Halyomorpha halys, among the most dangerous global crop-threatening pests. A 4-year survey that combined active search and a crowdsourcing approach made the tracking of its spread and investigation of its spatiotemporal dynamics possible, showing the functionality of coordinated multiactor approach in data collection.
Native to China, Japan, Korea, and Taiwan, the brown marmorated stink bug, Halyomorpha halys (Sål) (Hemiptera: Pentatomidae) was first detected in the United States in the mid-1990s. Since ...establishing in the United States, this invasive species has caused significant economic losses in agriculture and created major nuisance problems for home and business owners, especially in the mid-Atlantic region. Basic and applied questions on H. halys have been addressed in its native range in Asia since the mid-1900s and the research outcomes have been published in at least 216 articles from China, Japan, and the Republic of Korea. In Asia, H. halys is described as an occasional or outbreak pest of a number of crops such as apple, pear, persimmon, and soybeans. This species is considered a nuisance pest as well, particularly in Japan. This review summarizes 100 articles primarily translated from Chinese, Japanese, and Korean to English. The content of this review focuses on the biology, ecology, and management of H. halys in Asia, with specific emphasis on nomenclature, life history, host range, damage, economic importance, sampling and monitoring tools, and management strategies. This information from the native range of H. halys provides greater context and understanding of its biology, ecology, and management in North America.
Accurate identification of parasitoids is crucial for biological control of the invasive brown marmorated stink bug,
Halyomrpha halys
(Stål). A recent work by Talamas et al. (2017) revised the ...Palearctic fauna of
Trissolcus
Ashmead, egg-parasitoids of stink bugs, and treated numerous species as junior synonyms of
T. semistriatus
(Nees von Esenbeck). In the present paper, we provide a detailed taxonomic history and treatment of
T. semistriatus
and the species treated as its synonyms by Talamas et al. (2017) based on examination of primary types, molecular analyses and mating experiments.
Trissolcus semistriatus
,
T. belenus
(Walker),
T. colemani
(Crawford), and
T. manteroi
(Kieffer) are here recognized as valid and a key to species is provided. The identification tools provided here will facilitate the use of
Trissolcus
wasps as biological control agents and as the subject of ecological studies.
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