Dispersal ofRhinocyllus conicusfor Biocontrol of Musk Thistle

Weed Science ◽  
1976 ◽  
Vol 24 (1) ◽  
pp. 59-62 ◽  
Author(s):  
J. M. Hodgson ◽  
N. E. Rees
Keyword(s):  
Seed Production ◽  
Carduus Nutans ◽  
Rhinocyllus Conicus ◽  
Made In

A weevil [Rhinocyllus conicus(Froelich)] host specific toCarduus, Cirsium, Silybum, andOnopordum, was introduced into Gallatin County, Montana, for biocontrol of musk thistle (Carduus nutansL.). Releases were made in 1969, 1971, 1972, and 1973 on local musk thistle infestations. The insects became established and overwintered successfully. In 1974,R. conicuswas found over a 1,280-km2area of the county in seed heads of musk thistle. Weevil larvae severely infected the primary flowers, but only a few secondary and later flowers were attacked. Seed production from infected primary flowers was greatly reduced, and other factors influenced reduction of seeds from secondary and later flowers.

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.

Establishment of Rhinocyllus conicus (Coleoptera: Curculionidae) in Georgia for Control of Musk Thistle

1993 ◽  
Vol 28 (2) ◽  
pp. 213-217 ◽  
Author(s):  
G. D. Buntin ◽  
R. D. Hudson ◽  
T. R. Murphy
Keyword(s):  
Biological Control ◽  
Release Point ◽  
Carduus Nutans ◽  
Mature Adults ◽  
Initial Release ◽  
Rhinocyllus Conicus

Rhinocyllus conicus Froelich was introduced and successfully established at 21 sites in northern Georgia for biological control of musk thistle, Carduus nutans L. A total of 9,310 adults were released from 1990 through 1992. Releases of reproductively mature adults in the spring were much more successful than summer releases of teneral adults. Progeny were observed in all spring-release sites, and population increases occurred at most sites one and two years after release. Consumption of infested capitula by cattle reduced R. conicus numbers at some sites. After two years, weevils had dispersed up to 0.6 km from the initial release point. Transfer of R. conicus to new sites in Georgia will begin in 1993.

THE BIOLOGY OF CANADIAN WEEDS.: 89. Carduus nutans L. and Carduus acanthoides L.

1988 ◽  
Vol 68 (4) ◽  
pp. 1053-1068 ◽  
Author(s):  
A. M. DESROCHERS ◽  
J. F. BAIN ◽  
S. I. WARWICK
Keyword(s):  
Biological Control ◽  
Seed Production ◽  
Germination Rate ◽  
Effective Means ◽  
Western Canada ◽  
Control Methods ◽  
Carduus Acanthoides ◽  
Carduus Nutans ◽  
Introduced Weeds

Carduus nutans L. and C. acanthoides L. are introduced weeds, primarily of roadsides, fields and pasturelands. Both species occur in eastern and western Canada with C. nutans more common than C. acanthoides in western Canada. High seed production and germination rate on open soil contribute to the success of the species as weeds, as do the spiny leaves and stems which deter grazing by animals. Mowing or the application of hormone-like herbicides are both effective means of control. Biological control methods have also been used for both species, but have been most successful in the control of C. nutans.Key words: Musk thistle, nodding thistle, plumeless thistle, Carduus spp.

scholarly journals EFFECTS OF GROWING CONDITIONS ON CROSSING SUCCESS IN DIFFERENT POTATO(Solanum tuberosum L.)CROSSES

AGROFOR ◽  
2016 ◽  
Vol 1 (3) ◽  
Author(s):  
Güngör YILMAZ ◽  
Ahmet KINAY ◽  
Nejdet KANDEMİR ◽  
Şaziye DÖKÜLEN
Keyword(s):  
Solanum Tuberosum ◽  
High Altitude ◽  
Open Field ◽  
Seed Production ◽  
Solanum Tuberosum L ◽  
Hybrid Seeds ◽  
Low Altitude ◽  
Growing Conditions ◽  
Number Of Seeds ◽  
Made In

This study was carried out to determine the effect of growing conditions underdifferent altitudes on seed production in different potato crosses in Tokat Provinceof Turkey in 2015. Plants were grown and crosses were made in open field or nethouse in Tokat location (altitude 600 m asl.), open field or net house in Artovalocation (altitude 1200 m asl.), or controlled polycarbonate greenhouse. Fifteendifferent crosses were made between 12 parent cultivars. Production of hybridpotato seed was considered “crossing success”. Results showed that parentcultivars and cross combinations affected crossing success and no seeds wereproduced from some combinations while some combinations produced abundantseeds. The highest number of seeds were produced in controlled polycarbonategreenhouse, whereas very low amount of seeds were produced under low altitude(600 m asl.) open field conditions. Polycarbonate greenhouse produced 47.3% ofall seeds, while low altitude net house produced 19.8%, high altitude open fieldproduced 15.8%, high altitude net house produced 13.6% and low altitude openfield produced 3.5%. It was concluded that for a high crossing success, potatocrossing should be made by controlled polycarbonate greenhouse conditions and 23C0 day / 17 C0 night temperatures produced more hybrid seeds.

Establishment in Missouri ofRhinocyllus conicusfor the Biological Control of Musk Thistle(Carduus nutans)

Weed Science ◽  
1978 ◽  
Vol 26 (2) ◽  
pp. 188-190 ◽  
Author(s):  
Benjamin Puttler ◽  
S. H. Long ◽  
E. J. Peters
Keyword(s):  
Biological Control ◽  
Release Site ◽  
Carduus Nutans ◽  
Rhinocyllus Conicus ◽  
Bracon Mellitor

A weevil,(Rhinocyllus conicusFroelich) was introduced into Missouri in 1975 to aid in reducing populations of musk thistle,(Carduus nutansL.). The weevil was recovered in 1976 from as far as 3.2 km from the release site and 4.8 km in 1977. Infestation levels of flower heads at the release site ranged from 46 to 90%. Native parasites(Bracon mellitorSay) and [Aliolus curculionis(Fitch)] were reared from weevil larvae.

Effect of a Weevil,Rhinocyllus conicus, on Musk Thistle (Carduus thoermeri) Seed Production

Weed Science ◽  
1982 ◽  
Vol 30 (2) ◽  
pp. 136-140 ◽  
Author(s):  
Melvin K. McCarty ◽  
William O. Lamp
Keyword(s):  
Seed Production ◽  
Infestation Rate ◽  
The Third ◽  
Seed Head ◽  
Rhinocyllus Conicus ◽  
Initial Sampling ◽  
Viable Seeds ◽  
Infested Site

Three musk thistle (Carduus thoermeriWeinm.) sites that were infested with a weevil (Rhinocyllus conicusFroel.) and a fourth non-infested site were evaluated for numbers of insects and seeds per seed head. At four successive weekly intervals, seed heads were sampled just after flowering. Initial sampling was in 1978 and was repeated in 1979. Weevil incidence in heads blooming during the first week was 6.7/head in 1978 and 28.0 in 1979. At infested sites, production of fully developed seeds averaged 28% less than at the non-infested site in 1978 and 78% less in 1979. Heads that were in bloom during the fourth sampling week had an infestation rate less than one weevil/head in both years. Fully developed seeds germinated well (96 to 99%) and were not affected by date of bloom. Because many heads bloomed during the third and fourth weeks, a large number of viable seeds were still produced at infested sites.

Physiology of gibberellins in conifers

1977 ◽  
Vol 7 (2) ◽  
pp. 299-325 ◽  
Author(s):  
R. P. Pharis ◽  
C. G. Kuo
Keyword(s):  
Seed Production ◽  
Vegetative Growth ◽  
Growth And Development ◽  
Tree Breeding ◽  
Early Flowering ◽  
Progeny Testing ◽  
Screening Techniques ◽  
Exogenous Application ◽  
Development Processes ◽  
Made In

The literature on endogenous gibberellins (GAs) of conifers, and on processes correlated with changes in GA-like substances, or processes affected by exogenous application of GAs is reviewed. It is now apparent that GAs mediate or influence many different growth and development processes in conifers, although just how they evoke the observed responses remains obscure.Practically, the use of certain GAs on conifers should allow advances to be made in the areas of tree breeding (i.e. the promotion of early flowering) and enhancement and regularization of seed production. The possible use of GAs to enhance early vegetative growth is feasible for many species. The use of endogenous GA levels, rate of synthesis, or metabolism as screening techniques in progeny testing, while still speculative, appears attractive.

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