scholarly journals Nickende Distel – Blume des Jahres 2008

2018 ◽  
Vol 72 (2) ◽  
pp. 93-96
Author(s):  
Kurt Baumann
Keyword(s):  
Carduus Nutans

Die Nickende Distel (Carduus nutans) ist Blume des Jahres 2008. Ihr äußeres Erscheinungsbild, ihre Biologie und Ökologie werden vorgestellt. Unterschiede zu anderen Disteln werden erwähnt.

Interspecific competition between Rhinocyllus conicus and Urophora soistitialis L on nodding thistle in Canterbury

2005 ◽  
Vol 58 ◽  
pp. 140-147 ◽  
Author(s):  
M.R. McNeill ◽  
C.J. Fletcher
Keyword(s):  
Interspecific Competition ◽  
Insect Species ◽  
Carduus Nutans ◽  
Rhinocyllus Conicus ◽  
Microctonus Aethiopoides

Nodding thistle receptacle weevil Rhinocyllus conicus and gallfly Urophora solstitialis attack the capitula of nodding thistle Carduus nutans L Between 31 October and 15 December 2003 the phenology of both R conicus and U solstitialis was studied at a dryland site in Canterbury Adult R conicus were more numerous than U solstitialis on capitula throughout the experiment Larvae of R conicus were first found on 11 November (15 of capitula infested) and peaked on 2 December with 53 of capitula infested Only 3 of capitula were infested by U solstitialis Adult R conicus or U solstitialis emerged from 79 of the selected primary and secondary capitula The majority of infested capitula (81) contained only R conicus 2 contained only U solstitialis while 17 contained both insect species Parasitism of R conicus by the braconid parasitoid Microctonus aethiopoides was low and occurred when most weevil eggs had been laid

FURTHER STUDIES ON NATURAL SELECTION AMONG HYBRIDS OF CARDUUS ACANTHOIDES AND CARDUUS NUTANS

1964 ◽  
Vol 42 (12) ◽  
pp. 1605-1613 ◽  
Author(s):  
R. J. Moore ◽  
G. A. Mulligan
Keyword(s):  
Natural Selection ◽  
Chromosome Number ◽  
Parental Species ◽  
Experimental Studies ◽  
Great Decrease ◽  
Carduus Acanthoides ◽  
Carduus Nutans ◽  
Experimental Plots ◽  
Better Than ◽  
Made In

A third 5-year survey made in 1962 of Carduus acanthoides, C. nutans, and their hybrids in Grey Co., Ontario, revealed that a great decrease in these populations had occurred. C. acanthoides and hybrids similar to this species had survived better than C. nutans but very little spread of either species seemed to have occurred in 1957–1962. In experimental plots the hybrid has been made and backcrossed to the parental species. The species differ in chromosome number (C. acanthoides, 2n = 22; C. nutans, 2n = 16) and hybrids have intermediate numbers. Evidence was found from field and experimental studies that the progeny of the F1 hybrid included a greater proportion of seedlings with the higher chromosome numbers than with the lower and intermediate numbers. It is suggested that this selection may operate through the rejection of the longer chromosomes received from C. nutans, which, in certain zygotic combinations may constitute an excess of chromatin lethal to the zygote.

scholarly journals Impact of perennial ryegrass seeding densities on weed emergence growth and development

2000 ◽  
Vol 53 ◽  
pp. 38-43
Author(s):  
S.S. Seefeldt ◽  
M.L. Armstrong
Keyword(s):  
Perennial Ryegrass ◽  
Growth And Development ◽  
Field Experiments ◽  
Cirsium Arvense ◽  
Seeding Density ◽  
Senecio Jacobaea ◽  
Carduus Nutans ◽  
Weed Growth ◽  
Californian Thistle ◽  
Weed Emergence

Research was conducted to determine the effect of perennial ryegrass (Lolium perenne) sowing density on weed growth and development In glasshouse and field experiments perennial ryegrass was sown at rates of 0 5 10 20 40 and 80 kg/ha with 5 kg/ha of white clover (Trifolium repens) With increasing seeding density perennial ryegrass enhanced its competitiveness against all five of the weeds studied viz nodding thistle (Carduus nutans) Californian thistle (Cirsium arvense) Scotch thistle (Cirsium vulgare) ragwort (Senecio jacobaea) and hedge mustard (Sisymbrium officinale) In both trials increases in the perennial ryegrass seeding density did not reduce weed emergence However as perennial ryegrass density increased weed biomass decreased and time to flowering increased

scholarly journals First Report of Musk Thistle Rust (Puccinia carduorum) in California and Nevada

Plant Disease ◽  
2002 ◽  
Vol 86 (7) ◽  
pp. 814-814 ◽  
Author(s):  
D. M. Woods ◽  
M. J. Pitcairn ◽  
D. G. Luster ◽  
W. L. Bruckart
Keyword(s):  
Ribosomal Rna ◽  
Dna Sequences ◽  
Internal Transcribed Spacer ◽  
East Coast ◽  
Rust Fungus ◽  
The United States ◽  
Rust Disease ◽  
Carduus Nutans ◽  
Its1 And Its2 ◽  
Spacer Dna

Musk thistle, Carduus nutans L., is an introduced weed of pastures, rangelands, and natural areas in much of North America. Puccinia carduorum Jacky, an autoecious rust fungus from Turkey, has been evaluated for biological control of musk thistle since 1978, including a field study near Blacksburg, VA, from 1987 to 1990. After release of the fungus in Virginia, rusted musk thistle was found in eight eastern states by 1992, in Missouri by 1994 (1), and in Oklahoma by 1997 (2). A rust disease was discovered on musk thistle near Mt. Shasta, CA, on 22 September 1998, and near Mogul, NV, on 12 August 1999. The pathogen was identified as P. carduorum on the basis of pathogenicity on musk thistle and urediniospore morphology (ovate spores, 21 μm diameter, three germ pores equatorial in location, and echinulations over the upper two-thirds to three-quarters of urediniospores). Ribosomal RNA internal transcribed spacer DNA sequences (ITS1 and ITS2) were identical to those from the isolate obtained after the field release in Virginia, verifying that the California isolate is P. carduorum. The initial California infestation was observed on a few plants late in the season, and by September 2000, nearly 100% of plants were infected. The occurrence of P. carduorum in California is apparently the result of natural, unaided spread of the fungus on musk thistle from the East Coast of the United States. References: (1) A. B. A. M. Baudoin and W. L. Bruckart. Plant Dis. 80:1193, 1996. (2) L. J. Littlefield et al. Plant Dis. 82:832, 1998.

The Effects of Selected Herbicides on Musk Thistle (Carduus nutans) Viable Achene Production

1990 ◽  
Vol 4 (3) ◽  
pp. 482-486 ◽  
Author(s):  
K. George Beck ◽  
Robert G. Wilson ◽  
M. Ann Henson
Keyword(s):  
Growth Stages ◽  
Carduus Nutans ◽  
Flower Growth ◽  
Early Flower ◽  
Achene Production

Chlorsulfuron, metsulfuron, clopyralid, 2,4-D, picloram, and dicamba plus 2,4-D were spring-applied to musk thistle in rosette, bolting, bud, and early flower growth stages. All treatments reduced viable achene production at all musk thistle growth stages at Mcgrew, NE, and Longmont, CO. However, differences occurred at Evergreen, CO, among treatments and growth stages. No achenes developed at Evergreen when herbicides were applied during the rosette stage with dicamba plus 2,4-D, picloram, or metsulfuron at 21 g ai/ha or during bolting with chlorsulfuron or metsulfuron at 21 g/ha. Chlorsulfuron applied during early bloom reduced viable achene production over 99% compared to untreated plants and the picloram treatment.

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