Interpreting the host range of Peristenus digoneutis and Peristenus relictus (Hymenoptera: Braconidae) biological control agents of Lygus spp. (Hemiptera: Miridae) in North America

A study of the European parasitoids Peristenus digoneutis and Peristenus relictus, introduced for the biological control of Lygus lineolaris and Lygus hesperus, was conducted to determine their potential host ranges in North America. No-choice laboratory tests suggested that native Lygus spp. were equally likely to be hosts of both parasitoids. Other non-target Miridae were not suitable hosts for P. digoneutis but Amblytylus nasutus, Leptopterna dolabrata and Melanotrichus coagulatus may be suitable for development of P. relictus. Comparison with field data in North America and studies in Europe suggest that non-target Lygus spp. may be impacted by P. digoneutis while other non-target species would not. In contrast, the non-target Lygus spp. and at least several other non-target mirid species are likely to be impacted by P. relictus. Potential impact on non-target Lygus spp. would be highest in the Western North American bioregion where the greatest number of native species occurs. In the Eastern North American bioregion where the Lygus fauna consists of fewer, mainly widespread species, impacts on non-target Lygus spp. are expected to be minimal. It is recommended that post-release surveys be conducted to quantify potential impacts on non-target Lygus spp.

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► We examined the host range of Peristenus digoneutis and Peristenus relictus, biological control agents of Lygus spp. in North America.
► Interpretation of laboratory results and published field data indicate that P. digoneutis has a narrow host range compared P. relictus.
► Non-target impacts are likely to be less in the Eastern North American bioregion than in the Western North American bioregion.
► It is recommended that surveys be conducted in areas where P. digoneutis and P. relictus have been released to quantify impacts and validate laboratory and field results in the area of introduction.