Larval phenologies and parasitoids of two seed-feeding weevils associated with hoary cress and shepherd's purse (Brassicaceae) in Europe

In Europe, Ceutorhynchus turbatus Schultze and Ceutorhynchus typhae (Herbst) (Coleoptera: Curculionidae) feed on seeds from hoary cress and shepherd's purse (Cardaria draba (L.) Desv. and Capsella bursa-pastoris (L.) Medik.); both plants are invasive in North America. In North America, C. turbatus is a candidate for biological control of hoary cress, C. typhae is adventive, and both are sympatric with cabbage seedpod weevil (Ceutorhynchus obstrictus (Marsham)), an invasive alien pest of canola (Brassica napus L. and Brassica rapa L., Brassicaceae). We investigated host associations among C. turbatus, C. typhae, and their parasitoids in Europe. Of particular interest was host specificity of Trichomalus perfectus (Walker) and Mesopolobus morys (Walker) (Hymenoptera: Pteromalidae), candidates for biological control of C. obstrictus in North America. We found no evidence that T. perfectus attacks C. turbatus or C. typhae; however, M. morys was the most common parasitoid associated with C. turbatu

European ectoparasitoids of two classical weed biological control agents released in North America

The ceutorhynchine weevils Hadroplontus litura (F.) and Microplontus edentulus (Schultze) (Coleoptera: Curculionidae), are established in North America as biological control agents for Canada thistle, Cirsium arvense (L.) Scop., and scentless chamomile, Tripleurospermum perforatum (Mérat) M. Lainz (Asteraceae), respectively. In North America, both weeds occur sympatrically and in similar habitats as another ceutorhynchine, Ceutorhynchus obstrictus (Marsham) (cabbage seedpod weevil), an important pest of canola, Brassica napus L., and Brassica rapa L. (Brassicaceae). Ceutorhynchinae weevils released to control weeds in cultivated crops may serve as alternate hosts if agents released for biological control of C. obstrictus are not specific to that species. Parasitoids associated with M. edentulus and H. litura inflict similar levels of mortality on their hosts, yet a single species was associated with the latter host, whereas 13 species attacked the former. The stem-mining M. edentulus appears to be at some risk but not the root-crown feeding H. litura, should the parasitoids Trichomalus perfectus (Walker) and Mesopolobus morys (Walker) (Hymenoptera: Pteromalidae) be introduced as biological control agents of the silique-feeding C. obstrictus. These findings suggest that feeding niche may be an important criterion for developing a nontarget species test list for host-range testing of potential biological control agent

The stonefiles (Plecoptera) of Saskatchewan : a thesis submitted to the Faculty of Graduate Studies and Research in partial fulfilment of the requirements for the degree of Master of Science in the Department of Biology, University of Saskatchewan

Forty-one species belonging to 29 genera and eight families of the order Plecoptera are recorded from Saskatchewan. The distinguishing characters of the adults are described and keys are presented. The species collected include Pteronarcys dorsata (Say), Pteronarcella badia (Hagen), Taeniopteryx nivalis (Fitch), Oemopteryx fosketti (Ricker), Capnia coloradensis Claassen, C. confusa Claassen, C. gracilaria Claassen, c. vernalis Newport, Paracapnia angulata Hanson, Isocapnia crinita (Needham and Claassen), I. missourii Ricker, Utacapnia trava (Nebeker and Gaufin), Nemoura rickeri Jewett, Shipsa rotunda (Claassen), Amphinemura linda (Ricker), Zapada cinctipes (Banks), Malenka californica (Claassen), Podmosta delicatula (Claassen), Paraleuctra vershina Gaufin and Ricker, Leuctra ferruginea (Walker), Acroneuria abnormis (Newman), A. lycorias (Newman), Hesperoperla pacifica (Banks), Claassenia sabulosa (Banks), Paragnetina media (Walker), Perlesta placida (Hagen), Isoperla bilineata (Say), I. longiseta Banks, I. transmarina (Newman), I. patricia Frison, I. decolorata (Walker), I. marlynia Needham and, Claassen, I. petersoni Needham and Christenson, Arcynopteryx compacta (MacLachlan), Skwala parallela (Frison), Isogenoides colubrinus (Hagen), Isogenoides frontalis (Newman), Diura bicaudata (Linnaeus ) , Triznaka signata (Banks), Suwallia lineosa (Banks) and Hastaperla brevis (Banks). Nymphs of the following ten species are described for the, first time: O. fosketti, T. signata, S. lineosa, I. decolorata, N. rickeri, M. californica, P. delicatula, C. coloradensis, C. confusa and C. gracilaria. Keys to species are presented for mature nymphs except that nymphs of l. crinita and l. missourii are unknown, and nymphs of M. californica and A. linda are inseparable, as are nymphs of c. coloradensis from C. confusa and I. frontalis from I. colubrinus. The following information is presented for each species: selected literature references, distinguishing characters, biology and distribution which consists of a brief summary of the species range and a map showing Saskatchewan collection records. Taxonomically important characters are illustrated. Life history patterns and the seasonal succession of Saskatchewan Plecoptera are discussed. Saskatchewan stoneflies show a variety of life cycles ranging from being more than one year in duration to being univoltine. Some species with a one-year Iife history diapause as embryos, others do not. The post-glacial dispersal of stoneflies to Saskatchewan is discussed based on integration of the geographical and ecological distributions of extant species with the post-glacial history of Saskatchewan. The Saskatchewan stonefly fauna is derived mainly from post-glacial dispersal from refugia to the south and northwest of the ice sheets formed during the Wisconsin glaciation

Figs. 1–6 in Morphology of the Pre-Imaginal Life Stages of the Cabbage Seedpod Weevil, Ceutorhynchus obstrictus (Marsham) (Coleoptera: Curculionidae)

Figs. 1–6. Scanning electron micrographs of cabbage seedpod weevil. 1) Egg; 2) first-instar larva; 3) third-instar larva; 4) antenna; 5) apical antennal segment with sunken sensillae; 6) apical segment of maxillary palpus with sensillae.Published as part of <i>Dosdall, Lloyd M. & McFarlane, Michael A., 2004, Morphology of the Pre-Imaginal Life Stages of the Cabbage Seedpod Weevil, Ceutorhynchus obstrictus (Marsham) (Coleoptera: Curculionidae), pp. 45-52 in The Coleopterists Bulletin 58 (1)</i> on page 47, DOI: 10.1649/594, <a href="http://zenodo.org/record/10104239">http://zenodo.org/record/10104239</a&gt

Morphology of the Pre-Imaginal Life Stages of the Cabbage Seedpod Weevil, Ceutorhynchus obstrictus (Marsham) (Coleoptera: Curculionidae)

Dosdall, Lloyd M., McFarlane, Michael A. (2004): Morphology of the Pre-Imaginal Life Stages of the Cabbage Seedpod Weevil, Ceutorhynchus obstrictus (Marsham) (Coleoptera: Curculionidae). The Coleopterists Bulletin 58 (1): 45-52, DOI: 10.1649/594, URL: http://dx.doi.org/10.1649/59

Fig. 7 in Morphology of the Pre-Imaginal Life Stages of the Cabbage Seedpod Weevil, Ceutorhynchus obstrictus (Marsham) (Coleoptera: Curculionidae)

Fig. 7. Third-instar larva of Ceutorhynchus obstrictus, habitus and spiracle.Published as part of <i>Dosdall, Lloyd M. & McFarlane, Michael A., 2004, Morphology of the Pre-Imaginal Life Stages of the Cabbage Seedpod Weevil, Ceutorhynchus obstrictus (Marsham) (Coleoptera: Curculionidae), pp. 45-52 in The Coleopterists Bulletin 58 (1)</i> on page 48, DOI: 10.1649/594, <a href="http://zenodo.org/record/10104239">http://zenodo.org/record/10104239</a&gt

Diamondback moth ecology and management: problems, progress, and prospects

Agricultural intensification and greater production of Brassica vegetable and oilseed crops over the past two decades have increased the pest status of the diamondback moth (DBM), Plutella xylostella L., and it is now estimated to cost the world economy US$4–5 billion annually. Our understanding of some fundamental aspects of DBM biology and ecology, particularly host plant relationships, tritrophic interactions, and migration, has improved considerably but knowledge of other aspects, e.g., its global distribution and relative abundance, remains surprisingly limited. Biological control still focuses almost exclusively on a few species of hymenopteran parasitoids. Although these can be remarkably effective, insecticides continue to form the basis of management; their inappropriate use disrupts parasitoids and has resulted in field resistance to all available products. Improved ecological understanding and the availability of a series of highly effective selective insecticides throughout the 1990s provided the basis for sustainable and economically viable integrated pest management (IPM) approaches. However, repeated reversion to scheduled insecticide applications has resulted in resistance to these and more recently introduced compounds and the breakdown of IPM programs. Proven technologies for the sustainable management of DBM currently exist, but overcoming the barriers to their sustained adoption remains an enormous challenge