Cabbage seedpod weevil (Coleoptera: Curculionidae): new pest of canola in northeastern North America

2001 ◽  
Vol 133 (5) ◽  
pp. 709-711 ◽  
Author(s):  
Jacques Brodeur ◽  
Luc-André Leclerc ◽  
Marc Fournier ◽  
Michèle Roy

The cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham) [= C. assimilis (Paykull)] (Colonnelli 1993), is a univoltine species native to Europe that feeds on canola and other oilseed cruciferous plants. The adult overwinters in debris and soil outside fields and colonizes canola at the blooming stage (Dosdall et al. 2001). Eggs are laid singly into the immature pods and each larva consumes five to seven seeds before cutting a hole in the pod to wriggle out and pupate in the soil (Dmoch 1965). Yield losses are difficult to assess because the plant compensates for bud and pod injuries caused by insects or pathogens (Lamb 1989). Nevertheless, pod feeding by larvae causes much damage, as canola yields can be reduced from 15 to 35% (Homan and McCaffrey 1993). Feeding by adults can also be significant, as it can reduce oil content, seed weight, and seed germination (Buntin et al. 1995).

2006 ◽  
Vol 138 (3) ◽  
pp. 285-291 ◽  
Author(s):  
Gary A.P. Gibson ◽  
David R. Gillespie ◽  
Lloyd Dosdall

AbstractThe species of Pteromalidae (Chalcidoidea) introduced to British Columbia, Canada, from Europe in 1949 as Trichomalus fasciatus (Thomson, 1878), Xenocrepis pura Mayr, 1904, and Habrocytus sp. for classical biological control of Ceutorhynchus obstrictus (Marsham, 1802) (Coleoptera: Curculionidae) are shown to be misidentifications of Trichomalus perfectus (Walker, 1835), Mesopolobus morys (Walker, 1848), and Stenomalina gracilis (Walker, 1834), respectively. Species reared subsequently from seedpods of Brassica spp. (Brassicaceae) in British Columbia and reported in the literature under the first three names are shown to be misidentifications of, respectively, Trichomalus lucidus (Walker, 1835), Mesopolobus moryoides Gibson, 2005, and one or both of Pteromalus puparum (L., 1758) and T. lucidus. There is no evidence that either T. perfectus or M. morys established in North America, but S. gracilis is newly recorded from southern British Columbia based on specimens reared from Brassicaceae seedpods in 2004 and 2005.


2011 ◽  
Vol 143 (4) ◽  
pp. 399-410 ◽  
Author(s):  
Franck J. Muller ◽  
Lloyd M. Dosdall ◽  
Peter G. Mason ◽  
Ulrich Kuhlmann

AbstractIn 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. turbatus.


2007 ◽  
Vol 97 (4) ◽  
pp. 387-397 ◽  
Author(s):  
H. Baur ◽  
F.J. Muller ◽  
G.A.P. Gibson ◽  
P.G. Mason ◽  
U. Kuhlmann

AbstractFour species of Mesopolobus Westwood were reared as parasitoids of Ceutorhynchinae hosts in Europe during surveys in 2000–2004. An illustrated key is given to differentiate the four species, M. gemellus Baur & Muller sp. n., M. incultus (Walker), M. morys (Walker) and M. trasullus (Walker), plus M. moryoides Gibson, a parasitoid of the cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham), in North America. Pteromalus clavicornis Walker is recognized as a junior synonym of M. incultussyn. n., and Pteromalus berecynthos Walker (also a junior synonym of M. incultus) is considered a correct original spelling. For Disema pallipes Förster (a junior synonym of Mesopolobus morys), a lectotype is designated. Mesopolobus morys is for the first time accurately associated with the seed weevil Ceutorhynchus turbatus (Schultze), a potential agent for classical biological control, of hoary cress, Lepidium draba L. (Brassicaceae), in North America. Mesopolobus gemellus is associated with another seed weevil, Ceutorhynchus typhae (=C. floralis) (Herbst), in pods of shepherd's purse, Capsella bursa-pastoris (L.) Medik. (Brassicaceae). Implications of the host–parasitoid associations are discussed relative to the introduction of species to North America for classical biological control of the cabbage seedpod weevil.


2004 ◽  
Vol 39 (3) ◽  
pp. 350-361 ◽  
Author(s):  
Andrew S. Fox ◽  
Scott R. Shaw ◽  
Lloyd M. Dosdall ◽  
Byron Lee

Microctonus melanopus (Ruthe) were reared and dissected from adult cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham), collected in southern Alberta in 2000 and 2001, and M. melanopus females were collected near Creston, British Columbia in 2001. These collections represent the first records for this European species in Canada. Previously published records of M. melanopus in North America are from the northwestern United States. A first diagnosis for adult female M. melanopus is provided that places M. melanopus in Loan's (1969) key for Microctonus species of North America, north of Mexico. Scanning electron photomicrographs of female morphology are provided to illustrate important diagnostic characters: the mesonotal sculpture with a distinct median longitudinal carina posteriorly, and the sculpture of metasomal tergite 1 with costae distinctly converging posteriorly. It is probable that M. melanopus has long been established in the southern interior of British Columbia because its host, C. obstrictus, has occurred there for many years. The occurrence of M. melanopus in southern Alberta is likely more recent, as its host only recently dispersed to that region. Rates of parasitism of C. obstrictus by M. melanopus, with one exception, were low in southern Alberta (<10%), and only one parasitized weevil was found on spring-seeded Brassica napus L., the primary brassicaceous oilseed crop associated with the weevil on the Canadian prairies. We hypothesize that M. melanopus will not provide substantial control of C. obstrictus in the mixed grassland ecoregion of its new range.


2005 ◽  
Vol 137 (4) ◽  
pp. 381-403 ◽  
Author(s):  
Gary A.P. Gibson ◽  
Hannes Baur ◽  
Bryan Ulmer ◽  
Lloyd Dosdall ◽  
Franck Muller

AbstractPrevious identifications in North America of Trichomalus perfectus (Walker, 1835) and Mesopolobus morys (Walker, 1848) (Chalcidoidea: Pteromalidae), the principal chalcid parasitoids of the cabbage seedpod weevil (Ceutorhynchus obstrictus Marsham, 1802) in Europe, are shown to be misidentifications of Trichomalus lucidus (Walker, 1835) and Mesopolobus (Xenocrepis) moryoidessp. nov., respectively. Necremnus duplicatus Gahan, 1941 (Chalcidoidea: Eulophidae) is synonymized formally under Necremnus tidius (Walker, 1839) syn. nov., confirming a previous, tentative synonymy. Both sexes of N. tidius, M. moryoides, and T. lucidus are illustrated and compared with those of similar species using macrophotography and scanning electron microphotography. Hypotheses are offered to explain why the principal chalcid parasitoids of the cabbage seedpod weevil differ between North America and Europe and how the three treated species came to be in North America.


Plant Disease ◽  
1998 ◽  
Vol 82 (7) ◽  
pp. 826-829 ◽  
Author(s):  
D. D. Hoffman ◽  
G. L. Hartman ◽  
D. S. Mueller ◽  
R. A. Leitz ◽  
C. D. Nickell ◽  
...  

Sclerotinia stem rot (SSR) is one of the most important diseases of soybean in the United States. Five maturity group III cultivars, Asgrow A3304 STS (A3304), Pioneer Brand 9342 (P9342), Pioneer Brand 9381 (P9381), Probst, and Yale, grown in fields in east-central Illinois, were used to determine the relationship of SSR incidence to yield, 100-seed weight, seed protein and oil content, visual seed quality, and seed germination. In addition, the number of sclerotia in seed samples and the seedborne incidence of Sclerotinia sclerotiorum were determined. For each cultivar, at least 23 two-row plots, 3 m long, that represented a range of SSR incidence from low to high, were used to count the number of plants with and without SSR stem symptoms and were used to estimate yields and evaluate seed quality. Disease incidence ranged from 2 to 45% for Probst, 0 to 65% for P9381, 0 to 68% for P9342, 1 to 93% for Yale, and 0 to 95% for A3304. Regression of yields on SSR incidences for each cultivar was significant (P < 0.05); for every 10% increase in SSR incidence, yields were reduced by 147, 194, 203, 254, and 263 kg/ha for Probst, A3304, P9342, Yale, and P9381, respectively. Disease incidence was negatively correlated (P < 0.05) with seed germination for all cultivars but Probst, and to oil content and seed weight for P9381 and Yale. Disease incidence was positively correlated (P < 0.05) with seed quality for all cultivars and to the number of sclerotia in harvested seeds for P9342, P9381, and Probst. The seedborne incidence of S. sclerotiorum was 0.3, 0.3, 0.3, 0.4 and 0.7% in A3304, P9381, Yale, Probst, and P9342, respectively, and represents a significant potential for further spread of this pathogen and disease.


Genetika ◽  
2021 ◽  
Vol 53 (1) ◽  
pp. 157-166
Author(s):  
Velimir Radic ◽  
Igor Balalic ◽  
Milos Krstic ◽  
Ana Marjanovic-Jeromela

Five different rapeseed genotypes were tested. The following traits were considered: seed yield, seed germination, seed oil content, 1000 seed weight and seed protein content and they were used to determine whether there is significant or nonsignificant correlation. Highest average results were determined in genotype G-3 (yield 2.544 kg; germination 90%; 1000 seed weight 4,30 g; oil content 45,31% and protein content 19,83%) while G-5 (1.838 kg; 87%; 3,50 g; 44,77% and 17,28%) had the lowest average result of observed parameters. Highly significant positive correlations were found while comparing seed yield with 1000 seed weight (0.753**) and protein content (0.726**). High significant positive correlation were also determined comparing seed germination with 1000 seed weight (0.832**) and protein content (0.892**). Also high significant correlation was determined comparing 1000 seed weight and protein content (0.812**). Positive significant correlations were found by comparing seed yield and seed germination (0.644*). Path analysis indicated highest significant positive direct effect of 1000 seed weight (0.716**) and protein content (0.666**) on seed yield. High but negative significant value had seed germination (-0.645**). In the study of indirect effects on seed yield, none of significant effects were determined. The study of direct effects on oil content showed that the seed germination had high significant positive effect (-1.296**) on oil content. Significant but hot high effect has seed yield (0.556*). In other two traits it was determined negative high significant effects (1000 seed weight - 0.797** and protein content - 0.717**) on seed oil content. The existence of indirect significant effects on oil content in four cases was determined.


2011 ◽  
Vol 143 (5) ◽  
pp. 524-537 ◽  
Author(s):  
P.G. Mason ◽  
J.H. Miall ◽  
P. Bouchard ◽  
D.R. Gillespie ◽  
A.B. Broadbent ◽  
...  

AbstractSurveys were conducted to determine the parasitoid communities associated with the cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham), an important invasive pest of canola in Ontario and Quebec, Canada. More than 18 species of Chalcidoidea (Hymenoptera) were associated with this pest through mass rearings from canola siliques. In southwestern Ontario, the most abundant species were a species of Chlorocytus Graham (23.6%–48.6%), Lyrcus perdubius (Girault) (0%–53%), L. maculatus (Gahan) (2.8%–14.7%), and species of Pteromalus Swederus (0.6%–23.1%) (Pteromalidae). In contrast, the most abundant species in Quebec were Trichomalus lucidus (Walker) (Pteromalidae) (33.3%–56.4%), unidentified Eulophidae (2.1%–39.1%), Mesopolobus gemellus Baur and Muller (Pteromalidae) (1.3%–21.4%), and Necremnus tidius (Walker) (Eulophidae) (11.5%–19.3%). In the Ottawa, Ontario, area, parasitoids were first recovered in 2008, and Trichomalus perfectus (Walker) (Pteromalidae), M. gemellus, and species of Pteromalus were most prevalent. Mesopolobus gemellus and T. perfectus are reported in North America for the first time. Although existing communities appear to provide substantial parasitism (e.g., 6.3%–26.3% in 2006), species composition varies among years and differs from that in other regions in North America. Thus, parasitism levels and parasitoid communities of the cabbage seedpod weevil should be monitored to assess whether these will increase or there is a need to introduce more host-specific species from Europe that could provide greater mortality.


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