Performance of a Native Butterfly and Introduced Moth on Native and Introduced Lineages of Phragmites australis

This study examined the performance of Poanes viator (Edwards) (Hesperiidae), a native North American skipper, and Rhizedra lutosa (Hübner) (Noctuidae), an introduced moth, reared on native and non-native, invasive lineages of Phragmites australis. Poanes viator is a generalist on monocots and larvae were also fed leaves of Zizania aquatica, a native macrophyte that the skipper commonly uses as a host plant. Larval survival and duration, pupal weight, and pupation time were compared for P. viator feeding on leaf tissue and R. lutosa feeding on rhizomes of either native or introduced plants. We also tested an artificial diet supplemented with P. australis rhizome powder as a potential food for rearing other stalk and rhizome boring Lepidoptera. In experiments using excised plant tissues, some individuals of both species fed and developed to the pupal stage on native and introduced plants, but overall, larval survival rates were low. Plant species/haplotype identity did not cause strong differences in larval survival for either species. However, P. viator larvae only pupated when feeding on native plants (Zizania aquatica and native P. australis haplotypes), whereas R. lutosa successfully pupated on both native and introduced P. australis. Although larval survival was low, 100% of P. viator and 95% of R. lutosa that reached the pupal stage emerged as adults. Rhizedra lutosa larvae fed an artificial diet supplemented with P. australis rhizome powder had significantly greater survival and pupal weights, and shorter pupation times than larvae fed rhizomes only. Several specialist Lepidopteran species are being considered for approval as biological control agents for the non-native P. australis haplotype, and the convenience and increased larval performance make this artificial diet a good alternative for rearing organisms

Host specificity and risk assessment of Archanara geminipuncta and Archanara neurica, two potential biocontrol agents for invasive Phragmites australis in North America

Invasive Phragmites australis is widespread in North America and despite decades of management and large annual expenditures (\u3e5 million US$) using physical and chemical means, local populations and the species range are expanding. Allowing continued expansion does not only threaten native wetland biota but also an endemic North American subspecies Phragmites australis americanus. We used extensive multi-pronged investigations in Europe and North America to evaluate host specificity and impact of two European stem mining noctuid moths, Archanara geminipuncta and A. neurica. Both moth species are specific to the genus Phragmites and both show a very strong, but not absolute, preference for invasive P. australis over endemic P. australis americanus. No-choice tests or tests in small cages provided inconsistent results, but both moths showed consistently high preferences for introduced P. australis. Open field multiple-choice oviposition tests affirmed this; moths laid 6.5% of their eggs on native P. australis americanus. The native subspecies is further safeguarded by increased mortality of eggs and larvae when laid on, or developing in P. australis americanus. Phragmites populations in the southern US, particularly along the Gulf of Mexico, occur outside the climate range of these two temperate moth species. We consider potential threats to P. australis americanus demography due to A. geminipuncta and A. neurica attack to be far smaller than allowing expansion of invasive P. australis to continue. We therefore recommend release of these two biocontrol agents in North America

When misconceptions impede best practices: evidence supports biological control of invasive Phragmites

Development of a biological control program for invasive Phagmites australis australis in North America required 20 years of careful research, and consideration of management alternatives. A recent paper by Kiviat et al. (Biol Invasions 21:2529–2541, 2019. https://doi.org/10.1007/s10530-019-02014-9) articulates opposition to this biocontrol program and questions the ethics and thoroughness of the researchers. Here we address inaccuracies and misleading statements presented in Kiviat et al. (2019), followed by a brief overview of why biological control targeting Phragmites in North America can be implemented safely with little risk to native species. Similar to our colleagues, we are very concerned about the risks invasive Phragmites represent to North American habitats. But to protect those habitats and the species, including P. australis americanus, we come to a different decision regarding biological control. Current management techniques have not been able to reverse the invasiveness of P. australis australis, threats to native rare and endangered species continue, and large-scale herbicide campaigns are not only costly, but also represent threats to non-target species. We see implementation of biocontrol as the best hope for managing one of the most problematic invasive plants in North America. After extensive review, our petition to release two host specific stem miners was approved by The Technical Advisory Group for the Release of Biological Control Agents in the US and Canadian federal authorities

Potential for biological control of Phragmites australis in North America

Phragmites australis is a cosmopolitan plant that is undergoing a population explosion in freshwater and tidal wetlands on the east coast of North America. The rapid spread of P. australis in recent years and the virtual absence of native herbivores feeding on P. australis have led wetland ecologists to believe that either the species or more aggressive genotypes were introduced. The historical record of the occurrence of P. australis in North America and the scarcity of indigenous herbivores provide conflicting evidence for the status of the species as native or introduced. A comparison of P. australis populations from North America and other continents using advanced genetic techniques is underway to help determine the status of current and historic North American genotypes. Literature and field surveys reveal that of the 26 herbivores currently known to feed on P. australis in North America (many accidentally introduced during the last decade), only 5 are native. In Europe, over 170 herbivore species have been reported feeding on P. australis, some causing significant damage. Of these herbivores, rhizome-feeding species with considerable negative impact on P. australis performance include the lepidopterans Rhizedra lutosa (already present in North America), Phragmataecia castaneae, Chilo phragmitella, and Schoenobius gigantella. Stemboring moths in the genera Archanara and Arenostola and the chloropid fly Platycephala planifrons can have large detrimental impacts on P. australis in Europe and should be evaluated for their potential as biological control agents. In addition, the interaction of potential control agents with accidentally introduced P. australis herbivores needs to be evaluated in North America. Regardless of the results of the genetic analyses, any decision to introduce additional host-specific herbivores in an attempt to control P. australis will require considerable dialogue. This decision needs to weigh the current negative ecological and economic impacts of P. australis and the benefits and risks of a biological control program. © 2001 Elsevier Science

Complete host specificity test plant list and associated data to assess host specificity of Archanara geminipuncta and Archanara neurica, two potential biocontrol agents for invasive Phragmites australis in North America

Introduced European genotypes of Phragmites australis are invasive and widespread in North America. Decades of management using herbicide and other means have failed to control the species and its range and populations continue to expand. Allowing continued invasion threatens native wetland biota and an endemic North American subspecies Phragmites australis americanus. The lack of conventional management to control introduced P. australis triggered research to assess host specificity of two European noctuid moths, Archanara geminipuncta and Archanara neurica. These two species are considered particularly promising potential biocontrol agents for introduced P. australis. Here we provide the complete and approved list of test plants used to assess host specificity of A. geminipuncta and A. neurica. This includes data on neonate larval acceptance and survival under no-choice conditions, and oviposition tests for all plant species tested, including for different Phragmites subspecies currently occurring in North America. We further provide temperature profiles of select cities in the temperate native European distribution of the two noctuids and those in southern US climates. We used these long-term temperature records to assess whether overwintering eggs of A. geminipuncta and A. neurica can survive under climate conditions typical for the Gulf Coast region in North America. This data article refers to “Host specificity and risk assessment of Archanara geminipuncta and Archanara neurica, two potential biocontrol agents for invasive Phragmites australis in North America Biol. Control (2018)”. Keywords: Archanara, Biological weed control, Host specificity, Phragmites, Sub-species level specificity, Wetland

Host specificity of hypena opulenta: A potential biological control agent of vincetoxicum in North America

A biological control program has been initiated against the European swallow-worts Vincetoxicum nigrum (L.) Moench and V. rossicum (Kleopow) Barbar. (Family Apocynaceae) that have become invasive in North America. The leaf-feeding moth, Hypena opulenta Christoph (Lepidoptera: Erebidae), originating from eastern Europe, has been under measurement as a potential biological control agent of swallow-worts since 2006. In this study we measured the host range of H. opulenta by screening 82 potential host plant species for larval development under no-choice conditions. In addition, we also monitored female fecundity, longevity, and oviposition preference among suitable larval hosts. Successful larval development occurs only on Vincetoxicum spp. Partial larval development by one larva was observed on Boehmeria cyclindrica (L.) Sw. (Urticaceae) to the final instar, but this individual failed to pupate. Exploratory feeding occurred on Gonolobus stephanotrichus Griseb. (Apocynaceae) and Urtica dioica L. (Urticaceae), but all larvae failed to develop past the first and second instar, respectively. Additional testing with mature larvae on a subset of the plant species demonstrates that no species outside the genus Vincetoxicum are suitable for complete larval development of H. opulenta. The longevity and fecundity of females raised on each target weed are similar and gravid females do not display an oviposition preference among Vincetoxicum spp. Hypena opulenta does not present a risk to any native plant species or species of economic importance in North America. Petitions have been submitted for experimental open-field releases of H. opulenta in the United States and Canada. © 2012 Entomological Society of America

Host Specificity of Hypena opulenta

A biological control program has been initiated against the European swallow-worts Vincetoxicum nigrum (L.) Moench and V. rossicum (Kleopow) Barbar. (Family Apocynaceae) that have become invasive in North America. The leaf-feeding moth, Hypena opulenta Christoph (Lepidoptera: Erebidae), originating from eastern Europe, has been under measurement as a potential biological control agent of swallow-worts since 2006. In this study we measured the host range of H. opulenta by screening 82 potential host plant species for larval development under no-choice conditions. In addition, we also monitored female fecundity, longevity, and oviposition preference among suitable larval hosts. Successful larval development occurs only on Vincetoxicum spp. Partial larval development by one larva was observed on Boehmeria cyclindrica (L.) Sw. (Urticaceae) to the final instar, but this individual failed to pupate. Exploratory feeding occurred on Gonolobus stephanotrichus Griseb. (Apocynaceae) and Urtica dioica L. (Urticaceae), but all larvae failed to develop past the first and second instar, respectively. Additional testing with mature larvae on a subset of the plant species demonstrates that no species outside the genus Vincetoxicum are suitable for complete larval development of H. opulenta. The longevity and fecundity of females raised on each target weed are similar and gravid females do not display an oviposition preference among Vincetoxicum spp. Hypena opulenta does not present a risk to any native plant species or species of economic importance in North America. Petitions have been submitted for experimental open-field releases of H. opulenta in the United States and Canada. © 2012 Entomological Society of America

Grasses as appropriate targets in weed biocontrol: is the common reed, Phragmites australis, an anomaly?

Despite their importance as invasive species, there has been a hesitation to target grasses in classical biocontrol. This historic bias appears to be changing with multiple active research and release programs. Similarly, biocontrol workers appear to avoid targeting species with native congeners. These biases appear inappropriate as the ecological and entomological literature provide abundant evidence for sub-genus specificity for many herbivores, including those attacking grasses. The biocontrol program targeting Phragmites australis (Cav.) Trin. ex Steud (Poaceae) provides an informative example with endemic subspecies in North America and many sub-genus specific herbivores, including potential European control agents. Grasses and target weeds with congeneric native species require rigorous host range testing, similar to all other targets in current weed biological control programs. Furthermore, it appears prudent to ask petition reviewers and regulatory agencies to abandon their focus on results of no-choice studies and to distinguish between trivial feeding and demographic impacts

Establishment of parasitoids of the lily leaf beetle (Coleoptera: Chrysomelidae) in North America

Three larval parasitoids were imported from Europe to control the lily leaf beetle, Lilioceris lilii Scopoli (Coleoptera: Chrysomelidae), an accidentally introduced herbivore of native and cultivated lilies in North America. Tetrastichus setifer Thomson (Hymenoptera: Eulophidae) was introduced in Massachusetts in 1999, and was found to be established there in 2002. Subsequent releases of T. setifer were made and two additional parasitoids, Lemophagus errabundus Szepligeti (Hymenoptera: Ichneumonidae) and Diaparsis jucunda (Holmgren) (Hymenoptera: Ichneumonidae), were introduced. The establishment and distribution of the three parasitoids was evaluated through 2016. Tetrastichus setifer is now established in Massachusetts, Rhode Island, New Hampshire, Maine, Connecticut, and Ontario, Canada. Lemophagus errabundus is established in Massachusetts and Rhode Island, and D. jucunda is established in Massachusetts, Rhode Island, Connecticut, and Maine. All three parasitoids have spread at least 10km from release sites. The establishment of T. setifer is associated with a substantial reduction of L. lilii. In time it is likely that the parasitoids will spread throughout the North American range of L. lilii. This process can be accelerated to protect ornamental and native lilies by collecting and redistributing parasitoids to new infestations of L. lilii

Establishment of Hypena opulenta (Lepidoptera: Erebidae) on Vincetoxicum rossicum in Ontario, Canada

Hypena opulenta, a moth native to Ukraine, was released in 2013–2014 as a biocontrol agent for pale swallow-wort Vincetoxicum rossicum, an invasive vine, in Ottawa, Ontario, Canada. Blacklight trapping and surveys of feeding damage showed that H. opulenta has successfully established, increased in abundance and spread up to 2.0 km