Checklist of naturally occurring entomopathogenic microbes and nematodes in New Zealand

Eradicating the large white butterfly from New Zealand eliminates a threat to endemic Brassicaceae

In May 2010 the large white butterfly, Pieris brassicae L. (Lepidoptera: Pieridae), was discovered to have established in New Zealand. It is a Palearctic species that-due to its wide host plant range within the Brassicaceae-was regarded as a risk to New Zealand's native brassicas. New Zealand has 83 native species of Brassicaceae including 81 that are endemic, and many are threatened by both habitat loss and herbivory by other organisms. Initially a program was implemented to slow its spread, then an eradication attempt commenced in November 2012. The P. brassicae population was distributed over an area of approximately 100 km2 primarily in urban residential gardens. The eradication attempt involved promoting public engagement and reports of sightings, including offering a bounty for a two week period, systematically searching gardens for P. brassicae and its host plants, removing host plants, ground-based spraying of insecticide to kill eggs and larvae, searching for pupae, capturing adults with nets, and augmenting natural enemy populations. The attempt was supported by research that helped to progressively refine the eradication strategy and evaluate its performance. The last New Zealand detection of P. brassicae occurred on 16 December 2014, the eradication program ceased on 4 June 2016 and P. brassicae was officially declared eradicated from New Zealand on 22 November 2016, 6.5 years after it was first detected and 4 years after the eradication attempt commenced. This is the first species of butterfly ever to have been eradicated worldwide.

Severe Insect Pest Impacts on New Zealand Pasture: The Plight of an Ecological Outlier

New Zealand's intensive pastures, comprised almost entirely introduced Lolium L. and Trifolium L. species, are arguably the most productive grazing-lands in the world. However, these areas are vulnerable to destructive invasive pest species. Of these, three of the most damaging pests are weevils (Coleoptera: Curculionidae) that have relatively recently been controlled by three different introduced parasitoids, all belonging to the genus Microctonus Wesmael (Hymenoptera: Braconidae). Arguably that these introduced parasitoids have been highly effective is probably because they, like many of the exotic pest species, have benefited from enemy release. Parasitism has been so intense that, very unusually, one of the weevils has now evolved resistance to its parthenogenetic parasitoid. This review argues that New Zealand's high exotic pasture pest burden is attributable to a lack of pasture plant and natural enemy diversity that presents little biotic resistance to invasive species. There is a native natural enemy fauna in New Zealand that has evolved over millions of years of geographical isolation. However, these species remain in their indigenous ecosystems and, therefore, play a minimal role in creating biotic resistance in the country's exotic ecosystems. For clear ecological reasons relating to the nature of New Zealand pastures, importation biological control can work extremely well. Conversely, conservation biological control is less likely to be effective than elsewhere.

Coleopteran and Lepidopteran Hosts of the Entomopathogenic Genus Cordyceps sensu lato

Entomophthoralean and ascomycetous fungi are the two major groups known to parasitize arthropods in almost every terrestrial habitat of the earth. Within Ascomycota, Cordyceps sensu lato is a large genus with more than 400 spp. described on numerous orders of Arthropoda. Among the hosts of Cordyceps, Coleoptera and Lepidoptera are the two major orders. Out of the estimated 200 Cordyceps spp. recorded on coleopteran and lepidopteran hosts, we have documented 92 spp. based on the available information of their host species. Among coleopteran hosts, Scarabaeidae and Elateridae are the two major families. Similarly, among lepidopterans, Hepialidae is the largest host family. Cordyceps militaris shows the widest host range, extending to 2 orders, 13 families, and 32 spp. We hope such accumulative work will be useful as a quick reference for interested biologists, forest ecologists, biocontrol researchers, and fungal and insect taxonomists to apprehend host range and host specificities of Cordyceps fungi.

The Non-Photosynthetic Algae Helicosporidium spp.: Emergence of a Novel Group of Insect Pathogens

Since the original description of Helicosporidium parasiticum in 1921, members of the genus Helicosporidium have been reported to infect a wide variety of invertebrates, but their characterization has remained dependent on occasional reports of infection. Recently, several new Helicosporidium isolates have been successfully maintained in axenic cultures. The ability to produce large quantity of biological material has led to very significant advances in the understanding of Helicosporidium biology and its interactions with insect hosts. In particular, the unique infectious process has been well documented; the highly characteristic cyst and its included filamentous cell have been shown to play a central role during host infection and have been the focus of detailed morphological and developmental studies. In addition, phylogenetic analyses inferred from a multitude of molecular sequences have demonstrated that Helicosporidium are highly specialized non-photosynthetic algae (Chlorophyta: Trebouxiophyceae), and represent the first described entomopathogenic algae. This review provides an overview of (i) the morphology of Helicosporidium cell types, (ii) the Helicosporidium life cycle, including the entire infectious sequence and its impact on insect hosts, (iii) the phylogenetic analyses that have prompted the taxonomic classification of Helicosporidium as green algae, and (iv) the documented host range for this novel group of entomopathogens.

Natural host range and prevalence of the genus strongwellsea (Zygomycota: entomophthorales) in denmark

The natural occurrence and host range of species of the insect pathogenic fungal genus Strongwellsea [Zygomycota: Entomophthorales] were studied by extensive sampling and examination of adult Diptera [Cyclorrhapha]. The host range for Strongwellsea spp. was significantly enlarged. Three families were documented as new hosts: Muscidae (three species), Calliphoridae (one species), and Sarcophagidae (one species). Further, within the family Anthomyiidae six new host species were recorded and three new host species were documented in the Fanniidae. Strongwellsea castrans was identified as the pathogen in the Anthomyiids, while records from Fanniidae belonged to S. magna. The records of S. magna were the first outside the type locality (California). Primary conidia morphology indicated that muscid and calliphorid species were infected by three undescribed species of Strongwellsea. For the sarcophagid fly, no conidia were encountered, so the Strongwellsea species could not be identified. The tested sampling methods had each different advantages. Sweep netting and diagnosis in situ gave the best opportunity to sample a high number of infected dipterans per time unit spend, while sweep netting followed by incubation in the laboratory was the only method for the documentation of resting spores. The prevalence of S. castrans in the cabbage root fly Delia radicum was obtained by two methods: Samples collected by sweep net and incubated and water trap samples. Water trap captures gave higher prevalences of conidial infections than sweep-net captures. Measured prevalences of Strongwellsea spp. infections are therefore highly dependent on sampling method. The occurrence of resting spores of S. castrans in D. radicum was almost exclusively restricted to females and varied during the season. In samples from 1988 through 1993, no infected females in June contained resting spores, while 43.0% of the S. castrans-infected females from samples in August contained resting spores. During September and October, a decreasing proportion of S. castrans-infected D. radicum contained resting spores. The results document that species from the genus Strongwellsea are common fungal pathogens of adult flies from different families, occasionally with high prevalences. It also appears that the two described species of Strongwellsea, S. castrans and S. magna, have a range of dipterous host species that may always belong to a single family, Anthomyiidae and Fanniidae, respectively. Our data shows also that the host family Muscidae may be exploited by two new species of Strongwellsea. Copyright 1999 Academic Press.